Đề tài Ứng dụng phức chất để tách, phân chia, cô đặc, làm sạch bằng dung...

8/12/2019 ti ng dng phc cht tch, phn chia, c c, lm sch bng dung mi hu c, sc k

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Chng 6: ng dng phc cht tch, phn chia, c c, lm sch bng dung mi hu c, sc k

GVHD: Th.s Phm Hong Yn Nhm 2 Page 1 of 68

MC LCTrang

Phn 1: Li mu

Phn 2: Ni dung

A- Chit4

I/ Gii thiu .4

II/ Cc trng hp chit ...4

1, Chit cc hp cht ni phc4

2, Chit cc ion lin hp .7

3, Chit cc hp cht v c.....7

4, Chit cc phc clorua kim loi...8

5, Chit cc mui nitrat...9

6, Cc dung mi chnh dng chit..9

7, ngha ca phng php chit ..9

B- Chit thp cc phng php khc nhau10

I/ Chit trc quang101, Nguyn tc v csnh lng ca phng php11

2, Cc phng php nghin cu.11

3, Mt sthuc thhu cdng trong chit trc quang14

II/ Chit hunh quang...17

1, c tnh chung ca phng php18

2, Cc v dsdng phng php..19

III/ Chit hp th, pht x, hunh quang nguyn t..211, Chit hp thnguyn t22

2, Chit pht xnguyn t26

3, Chit hunh quang30

4, Chit ho phng x.32

C- Phc cht dng tch bng phng php sc k.....35

I/ Vi nt lch s...35

WWW.DAYKEMQUYNHON.UCOZ.COM


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II/ Phn loi Nguyn tc.35

1, nh ngha35

2, Phn loi...35

3, Cc lc lin kt trong sc k.384, Stng tc gia 3 thnh phn trong hsc k39

III/ Mt si lng dng trong sc k..40

1, Hsphn bKDv cch xc nh..40

2, Slin hgia tc di chuyn ca cht phn tch v KD..40

3, Thi gian lu tRv thi gian hiu chnh tR..41

4, Thtch lu Vmv thtch lu hiu chnh41

5, Hstch ...41

6, Sc k .41

7, a l thuyt42

8, phn gii v cch lm tng phn gii...43

9, Thuyt tc , phng trnh Van Deemter.43

Mt sthuc thhu cdng trong tch chit v sc k...45

Alizarin complexone46

Murexid498-Hydroxylquioline..51

ti v dvng dng phc cht trong phn chia, tch chit....55

Ti liu tham kho.72



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Phn 1: Li Mu

Trong cuc sng, con ngi lun lun mong mun tha mn v tp ng nhng nhu cu cnthit . Cuc sng cng hin i th nhng nhu cu y cng a dng, phong ph v i hi cht lngngy cng cao hn; nhu cu n ung, nhu cu c mt mi trng sng trong lnh, nhu cu tm hiunhng iu mi ltrong thgii sinh quyn. p ng nhng nhu cu th bmn ho phn tchra i, p ng c nhng nhu cu khm ph nhng cht mi, tm hiu thnh phn ca chng. Hinnay, cc phng php phn tch ang c ng dng rng ri trong cc nghnh khoa hc kthut vsn xut. Vi nhng thit bngy cng hon thin v hin i, skt hp tch bng my sc k vi ccloi u d khc nhau v x l cc s liu thc nghim trn my vi tnh bng nhng chng trnhchuyn dng, cho php khng nhng lm tng nhy v chnh xc ca cc php phn tch mcn tng ho tphp o cc thng svt l ca cc cht cho n cc qu trnh phn tch, rt ngnthi gian phn tch, p ng c nhu cu ca sn xut v nghin cu ca cc ngnh khoa hc ang

pht trin mnh m. Mt trong nhng bphn ca ho hc phn tch l Phc cht trong ho hc.Phc cht l loi hp cht c ng dng rng ri v ngy cng a dng trong hu ht cc lnhvc khc nhau nh ho hc, sinh hc, y hc, dc hc, nng nghip, cng nghip, phn tch mitrng, iu tra nhm khai thc cc ngun ti nguyn, khong sn ca t nc.

Spht trin ca ngnh ho hc phc cht c nhng ng gp to ln v quan trng cho nhiungnh khoa hc, kthut v kinh tquc dn.

Khoa hc, kthut hin i t ra cho ngnh ho hc phc cht nhng nhim vquan trnghn, phc tp hn. Cn phi nghin cu cc phng php phn tch c chnh xc cao, nhy caov chn lc cao, da trn vic ng dng cc phn ng to phc n ligan v a ligan nhm xcnh hm lng nhcc cht trong cc i tng phn tch khc nhau.

Trong phn tch mi phn tch v iu chcc loi vt liu, nhng cht siu tinh khit, phc chtng vai tr cc k quan trng. Phc cht ng vai tr quyt nh trong cc phng php tch, phnchia v lm sch cc cht, hp cht.

Trong ti tiu lun ny, di s hng dn nhit tnh ca Th.s Phm Hong Yn, nhmchng em cng tim hiu vNG DNG PHC CHT TCH, PHN CHIA, C C,LM SCH BNG DUNG MI HU C, SC K phn CHIT T HP VI CCPHNG PHP KHC NHAU

Tuy nhin do shn chvkin thc nn khng thtrnh khi nhng sai st d l nhnht. Vvy chng em rt mong nhn c nhng ng gp qu bu ca C v cc bn. Chng em chn thnh

cm n.



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Phn 2: Ni dung

A- ChitI/ Gii thiu

- Sphn bmt cht gia hai cht lng khng trn ln c thc dng nghin cu cccn bng to phc. Cht c phn bc thl ligan hay hp cht c cha kim loi. i hi sao chohai pha (mt trong hai pha ny thng l nc hay dung dch nc) khng trn ln vi nhau. i hiny c khi thc hin khng hon ton. Nu nhtan tng hca hai cht lng l ng kth cnphi tnh n sthay i ca mi trng v nh hng ca sthay i ny ln cc hng sto phc.Trong nghin cu cc cn bng to phc trong cc dung dch nc, ngi ta dng dung mi hu clm cht lng thhai. C thkim tra schit cc hp cht bng nhiu phng php. Phng phpchung hay dng cc ng v. Phng php ny cho php lm vic vi cc nng rt nhca cc kimloi, iu cho php nghin cu cc phc ca cc kim loi c trng cho sto ra cc phc a nhn.

- K thut thc nghim ca schit rt n gin. iu quan trng lm sao cho hai cht lngphi c bo ho ln nhau trc khi chit. nh gi hng scn bng th sphn bca cht cnphi c xc nh phthuc vo sthay i nng ca cc cu tca phn ng chit.II/ Cc trng hp chit1, Chit cc hp cht ni phc:

- Cc hp cht ni phc cn gi l cc hp cht vng cng cua hay cc chelat. Cc thucthhu cto vng cng c cng thc chung l HR. Cn bng chit c biu din bng phng trnhsau: nHR + Mn+ MRn + nH

+(dung mi) (nc) (dung mi) (nc)

Cn bng chit ny phthuc vo pH ca dung dch.

- Trong cc phc cht to thnh c cc loi lin kt phi tr sau: = S; = O; N



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Mt trong cc thuc th hu c thng c s dng chit l :

Dithizone- Dithizone c hnh thnh bi phn ngca phenylhydrazine vi carbon disulfide . Vic hnh thnhnh mt trung gian Diphenylthiocarbazid mt nc bngcch un nng trong mt methanolic KOH gii php chodithizone.

- Dithizone hnh thc phc hp vi cc ion kim loinng hnh thc phc hp n nh m khng tan trong ncnhng tan trong carbon tetrachloride. Cc gii php nydithizonates c mt mu c trng:

- Chng c thc da trn stoichiometry nhum v cnh trn o mu hoc trc quang cch xc nh cht vlng.- Cn cvo solubilities khc nhau ca cc ion kim loi v

kim loi phc dithizone trong chun khai khong cs dng. Vi iu ny, cc dung dch nc ca cc chtphn tch vi mt gii php tiu chun ca dithizone trongchloroform l chun .- Cn bng chnh khi chit l:

Mn+ + nHDz MDzn+ nH+

(nc) (dung mi) (dung mi) (nc)Ngoi ra cng phi kn cn bng

H+

+ D-z HDz pKa= 8,7(nc) (dung mi)

- Shnh thnh dithizonates phc vnhmt phng phpphn tch rt nhy cm xc nh du vt ca cc ion kimloi nng khc nhau. Cc gii hn pht hin ch l at 4:10 -8 g nng ngng l 1:1 250 000 Km c cho sdng mt chng trnh lm giu khai khong mt phalong 1:50 000 000, tc l, 1 mg trong 50 ml nc. Mt s

bng chng chng minh t 10-100 ppm .

Kt cu cng thc

Tng

Tn Dithizone

Tn khc

3 - (phenylamino) - 1-phenylimino

Thiourea(IUPAC)1,5 diphenylthiocarbazone

Tngcngthc

C 13H 12N 4S

SCAS 60-10-6

PubChem 657 262

M t

ngn

mu xanh-en bt tinh th

Thuc tnh

Khilngmol

256,33 g mol -1

Trngthi vtl

cnh

imnngchy

165-168 C (phn hy) [1]

hatan

- khng tan trong nc, ttrong ethanol [1]; trong carbontetrachloride v chloroformtt,vi sn xanh ha tan

Ion kim loi X Mu Kt cu cng thc

Fe , Mn , Cu , Co , Ni tm

Bi , Sn , Cd , Zn , Pbmu

Ag , Hg muvng



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8-hiroxiquinolin.Nhiu phc kim loi ca 8-hiroxiquinolin c chit rt thun li vo dungmi hu c. C thdin tqu trnh chit bng phng trnh:

2HQ(hc)+ M(n)2+ MQ2(hc)+ 2H

+(n)

R rng l cn bng chit ph thuc vo pH, do c th tch cc ion kim loi thng qua siu

chnh pH ca pha nc. Nhng thnghim trong thc t chng t rng, phng php ny rt tindng tch lng vt cc kim loi.Tartrates: Tartratl cc mui v este ca axit tartaric . Trong c bit tartrates kali ( cao rng )v mui Rochelle bi slin quan. Cc tartrat natri kali, ngoi ng sunfat , mt thuc thtrong thnghim ca Fehling cho vic gim ng. Natri tartrat rubidi ng mtvai tr trung tm trong vic lm sng t cu hnh tuyt i

ca enantiopure phn t.Thuc vi mt c bn nhm chcnng c s dng nh tartrates, vd, nhmui axit tartaric ca zolpideTartrate c th c t mu bimt phn ng hnh thnh phc tp ving (II) mui trong dung dch kim chng minh:2C4H4O6

2- + Cu2++ 2OH-[Cu(C4H3O6)2]4- + 2H2O

Ion tartrate, ng (II) cc ion v cc ion hydroxit phn ng viDitartratocuprat ion phc tp (II), xut hin xanh, v nc

Cupferron:Cupferron, mui amoni ca N-nitroso-N-phenylhydroxylamine, l mt thuc thchungcho cc complexation ca cc ion kim loi. Cng thc can l NH4[C6H5N (O)NO]. Anion Cc lin kt vi cccation kim loi thng qua cc nguyn toxy, hnhthnh cc vng chelate nm

-

- Cupferron c chun btphenylhydroxylamine v NO + ngun:C6H5NHOH + C4H9ONO + NH3NH4[C6H5N(O)NO] + C4H9OH



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2, Chit cc ion lin hp:- C thlm chuyn dch cn bng ca mt hno trong dung dch nc bng cch to cc

phc cht bn trong cc dung mi hu c thch hp. Cn bng cng dchuyn dch nu phc hu cca phc cht c vai tr quan trng hn so vi phn v cso vi phn v cca phc cht.

- chit anion ngi ta thng sdng cc cation hu csau y:- Cc mui tetraphenylasoni (C6H5)4As

+phn ly hon ton trong cc dung dch nc. Ion nyto vi cc anion: MnO4

-, IO4-, ClO4

-, RuO4-, ReO4

-, TeO4-, BF4

-nhng hp cht tan c trong dungmi hu c. Ion tetraphenylasoni cng to thnh cc hp cht tng tvi cc anion phc HgCl4

2-,SnCl6

2-, CdCl42-, ZnCl4

2-,Co(SCN)42-v cc anion ca mt s cht mu nhanion ca bromothimol

xanh.- Cc cation: R4Sb

+, R4P+, R4S

+, R4Se+ cng c nhng tnh cht tng t nh ion

tetraphenylasoni. Ion amoni bn ln thR4N+cng ha hp vi nhiu anion to thnh cc hp cht

cng dbchit nu snguyn tcacbon trong R4N+cng nhiu (V d: hp cht ca xetyl trimetyl

amoni hay n tetrapropylamoni dbchit). Hiu sut chit c tng ln nu anion l do catrion vckt hp vi gc hu c phc tp to nn.

- Nhiu bazhu cnhcc amin v cc cht mu bazc thtn ti di dng cation HB+vha hp c vi nhng anion v cto thnh nhng hp cht tan c trong cc dung mi hu c.

- Cc amin c mch nguyn tdi trong phn t, nh loi R3N nhng pH thch hp c thdng chit nhiu anion v c.

2R3N + H++ HSO4

- (R3NH)2SO4(Dung mi) (nc) (dung mi)

4R3N + 3SO42- + 4H+ + UO2

2+ UO2(R3NH)4(SO4)3(dung mi) (nc) (dung mi)

- Cc amin nh: tri-n-octylamin, metyldodexylamin, dng chit uran tcc dung dch sunfat.- Nhiu cht mu baz c khnng kt hp vi ion H+c dng chit cc anion. Trongtrng hp ny, dung dch chit c mu v c thdng nh lng bng phng php trc quang.

V d: xanh metylen (R) cho phn ng: R + H++ BF4- (RH)BF4

(dung mi) (nc) (dung mi)- Cc anion hu c, c bit l cc anion ca cc axit c mch cacbon di trong phn tc th

to vi cc cation v cnhng mui tan trong dung mi hu c, v danion ca axit peflooctanic, ionankylsunfat, ankylsunfonat.

- Ni tm li, chit anion, ngi ta cgng chn cation c mu v ngc li, chit cation,ngi ta chn cc anion c mu, v chn nhvy hp cht to thnh sc mu v sau khi chit c th

nh lng chng trong dung mi hu cbng phng php trc quang.3, Chit cc hp cht v c:

- Mt scht v cnh: brom, iot, nhiu phc cht khng bn trong cc dung dch nc (nhcc phc cht vi clorua, bromua, iodua, thioxyanat, cc axit d da, cc photphatvanadat,photphatmolybdat) u tan c trong cc dung mi hu c. tan ca cc cht trong cc dungmi hu ci khi rt ln, v vy c thchit mt lng ln ra khi dung dch nc. Ngi ta phnbit hai loi hp cht v c:

+ Mt scht v cnh: HgCl2, Br2, SO2, tan trong cc dung mi hu ctn ti dng phnt, khng phn ng vi cc dung mi .



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+ Cc cht khc khi chuyn vo cc dung mi hu cth ha hp vi dung mi to thnh hpcht phi tr.V d:st (III) clorua, uranylnitrat khi tan trong cc ete, este, xeton v ru th to thnh hp

cht phi tr vi dung mi.

- tlu ngi ta c thchit lng ln Fe(III) tnhng dung dch axit clohidric c bngetedietylic, lm nh vy c th tch Fe(III) ra khi Al (III), Fe(II), Ni(II), coban, mangan, Trongdung dch H2O tn ti ion Fe(H2O)6

3+. Cn trong dung dch HCl 6N, Fe(III) tn ti cc dng ion sau:Fe(H2O)6

3+ + Cl- FeCl(H2O)52+ + H2O

FeCl(H2O)52+ + Cl- FeCl2(H2O)4

+ + H2OFeCl2(H2O)4

+ + Cl

- FeCl3(H2O)3 + H2OFeCl3(H2O)3 + Cl

- FeCl4(H2O)2- + H2O

+ Khi nng HCl ln (hn 4N) th cn bng dch chuyn vpha to thnh ion FeCl4(H-2O)2

- (n gin thng chvit l FeCl4-). Trong dung dch nc ion FeCl4

-). Trong dung dchnc ion FeCl

4

-

scng hp thm proton H+to nn lin hp ion H+FeCl

4

- kh hn l trong mitrng khng phn cc nhete dietylic. Trong mi trng thhai (mi trng hu c), lin hpion FeCl4(R2O)2H bn vng hn v khng tan (R l gc C2H5hay H

+).+ Lin hp ion dng FeCl4(R2O)2H c th tn ti thay i t [FeCl4(R2O)2]2 n

[FeCl4(R2O)2H]4phthuc vo nng ca Fe(III).- Ngi ta c ththay ete dietylic bng ete izopropylic. Bng ete izopropylic c thchit c

cc nguyn tsau y tdung dch axit clohidric 6N: st (III), gali, vng (III), gecmani, asen (III) v(V), antimony (III) v (V), thic (II) v (IV), molipden (V) v Telu(IV).

- Tnh cht cc bromua gn ging cc clorua, trong a s trng hp bromua dbchit hnclorua.

4, Chit cc phc clorua kim loi:- Cc s liu bng 1 ch r rng, mt s rt ng k cc phc clorua kim loi b chit voietylete tdung dch axit clohiric 6M. Mt thng tin khc khng km phn quan trng l mt srtln cc ion kim loi khc hoc khng bchit hoc chbchit mt phn rt nhnhng iu kinnu trn. Nhvy l c ththc hin nhiu quy trnh chit rt c ch. Mt trong nhng quy trnh quantrng l tch st (III) (c 99%) khi sln cc kim loi khc.

V d:phn rt ln st trong cc mu thp hoc qung st c thc tch ra bng cch chittrc khi phn tch vt cc nguyn tnh: crom, nhm, titan v niken. Hp cht bchit dng linhp ion H3O

+FeCl-4. Phn trm st c chuyn vo tng hu c ph thuc vo hm lng axitclohiric trong tng nc (mt phn nhc chuyn li tng nc khi nng HCl thp hn 3Mv cao hn 9M) v mt mc no phthuc vo hm lng st.



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Bng 1: Chit phc clorua kim loi bng ietylete tdung dch HCl 6M

Phn trm bchit

Cc nguyn tv trng thi oxi ha

90-100 Fe (III) 99%; Sb(V) 99%* ; Ga(III)97% ; Ti(III) 95%* ; Au(III) 95%50-90 Mo(IV) 80-90% ; As(III) 80% ** ; Ge(IV) 40-60%

1-50Te(IV) 34% ; Sn(II) 15-30% ; Sn (IV) 17% ; Ir (IV) 5% ; Sb(I II)2,5%*

0As (V)* ; Cu(II) ; In(III) ; Hg(II) , Pt(IV) ; Se(IV) ; V(V) ; V(IV) ;Zn(II)

0Al(III) ; Bi(III) ; Cd(II) ; Cr (III) ; Co(II) ; Be(II) ; Fe(II) ; Pb(II) ;Mn(II);Ni(II) ; Os(VIII) ; Pb(II) ; Rh(III) ; Ag(I) ; Th(IV) ; Ti(IV) ;W(VI) ; Zr(IV)

* Isoprooyl ete c sdng nhiu hn ietylete

** 8M HCl c dung nhiu hn 6M.Metylizobutyl xeton cng chit c st tcc dung dch clorua st. Trong trng hp ny, hsphn btt hn mt cht so vi ietylete v cn c mt thun li khc l khng bbt la.5, Chit cc mui nitrat:Cc mui nitrat bchit la chn bng ietylete cng nhbng cc dung mihu ckhc.

V d:c thchit uran (VI) rt thun li khi cc nguyn tkhc nhch v thori bng ete tdung dch nc bo ha amoni nitrat v c nng axit nitric khong 1,5M Bismut (III) v st (III)nitrat cng bchit n mt mc nht nh nhng iu kin nhth.6, Cc dung mi chnh dng chit:

- Cc ete: Trc y ngi ta chdng ete etylic, nhng nhc im ca n l rt dbay hi v

tan nhiu trong nc. Hin nay trong s cc ete t tan trong nc, ngi ta thng dng eteizopropylic.

- Cc xeton: Tc dng chit ca cc xeton ni chung ging cc ete. Ngi ta thng dngmetylizobutyl axeton.

- Cc este: Tnh cht ca cc este ging nh cc ete v cc xeton. Ngi ta thng dngetylaxetat nhng n c nhc im l dbay hi v db thy phn. C thsdng amylaxetat tthn.

- Cc ru: Cc ru bc cao i khi c dng chit cc cht khng tan trong cc dung mikhc, nhng vic chit phc tp hn v cc ru d tan trong nc v nc cng d tan trongchng.

- Cc dung mi tr: Nu dng cc dung mi trnhcacbontetraclorua, cloroform, benzen, chit th stt hn cc dung mi khc v dung mi trny dtch khi cc dung dch nc. Trong s, cloroform tt hn cacbontetraclorua, nhng li t bn hn. n nh n, ngi ta thng thmvo 1% ru, nhng iu gy kh khn cho phn tch tip theo.

- Dung mi trn ln vi nc: i khi ngi ta thm vo dung dch nc cc dung mi hu ctrn ln vi nc lm gim hng sin mi ca dung dch, to iu kin thun li cho sto phcnng cao hiu sut chit.



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7, ngha ca phng php chit: Khnng ng dng ca phng php chit rt ln:- Chc mt snhcc cht v ctan c trong cc dung mi hu c, mt khc cc thuc th

hu cli to vi cc ion v cnhiu hp cht tan c trong dung mi hu cring bit hay hn hp

cc dung mi.- Thm mt dung mi thhai vo nc c thchuyn mt scht tmt dung dch nc vodung dch hu cv nhvy slm dch chuyn cn bng c lin quan n cht trong dung dchnc. Do c thto ra phng php tc ng ln cn bng thng c trong dung dch nc nhcnbng axit baz, cn bng oxi ha kh, cn bng to phc, cn bng kt ta,

- Bng cch chit c ththc hin vic tch hai cu tkhi nh hng ca nhau. Khi lm dchchuyn cn bng trong tng nc ta s lm thay i sphn bcc cht gia hai dung mi, do thc hin c vic tch rt chn lc.

- Chit l mt phng php c ngha cc kto ln, phng php chit c u im so vi ccphng php tch khc chtc chit ln, i khi chtrong vi pht cn bng t c, tng

ny tch khi tng kia rt nhanh, trnh c hin tng nhhp ph, cng kt.- Ngoi ra bng phng php chit cn c th lm giu lng vt cc nguyn tmt cch d

dng.

B- Chit thp vi cc phng php khc nhau:Bn thn phng php Chit l mt phng phptch chkhng phi l phng php phn tch. Vic chit thp vi mt phng php phn tch khcngha l sau khi chit tch cu tcn phn tch th ngi ta dng phng php phn tch kia nhlng cht . C cc loi phng php chit nhsau:

- Chit trc quang: sau khi chit tch sdng phng php trc quang nh lng- Chit hunh quang: sau khi chit tch sdng phng php phhunh quang phn tnh

lng- Chit hp th nguyn t: sau khi chit tch s dng phng php ph hp th nguyn t

(AAS) nh lng- Chit pht xnguyn t: sau khi chit tch sdng phng php phpht xnguyn t(AES)

nh lng- Chit hunh quang nguyn t: sau khi chit tch s dng phng php ph hunh quang

nguyn tnh lng- Chit ha - phng x: sau khi chit tch s dng phng php cc phng php phn tchphng xnhphRntgen (tia X) bao gm:

+ Phpht xtia X

+ Phhunh quang tia X+ Phnhiu xtia X

I/ Chit trc quang:Phng php chittrc quang cho php ta nng cao chn lc, nhy v cc nguyn t.

- Trong khi chit, khng phi cc nguyn tu c chit cc iu kin nhnhau. Do khichit sloi bt cc yu tcn trdo vy tng chn lc ca php phn tch.

- Khi chit, thng tmt thtch ln ca pha nc, phc mu c chuyn vo mt thtchnhdung mi hu c. Do vy y va c c va tng c nhy ca php xc nh trc quang.



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- Ngoi ra, pha hu cthng c hng sin mi v phn cc nhhn ng kso vi phanc, do vy phc bn hn, vic chuyn ion cn xc nh vo phc hon ton hn, tng c chnhxc v ng ca php xc nh.

- Thng th phc chit c vo dung mi hu cc hshp thtgam ln hn ng kso

vi i lng ny trong pha nc.- Tng tnhtrong pha nc, c thp dng mt phc trong pha hu cv php xc nh

chittrc quang ta cn nghin cu cc iu kin ti u vbc sng, thi gian, pH, nhit , nng thuc thv ion kim loi, khong tun theo nh lut Bear, ion cn, ng chun xc nh munhn to v mu tht.

- Trong php chit-trc quang th vic chn dung mi chit (hoc hn hp dung mi) c nghaquyt nh. Vic chn dung mi hoc hn hp dung mi thng da trn cu trc mu ca thuc thv cu trc chung ca phn tphc mu.1, Nguyn tc v csnh lng ca phng phpNguyn tc chung ca phng php phn tch trc quang

- Chuyn cu tthnh hp cht c khnng hp thnh sng.- o shp thnh sng ca hp cht to thnh v suy ra hm lng cht cn xc nh X.

Nguyn tc chung ca cc phng php phn tch nh lng- o quang ca dung dch mu.- So snh cng mu (hoc hp th quang) ca dung dch nghin cu vi dung dch

chun.Csnh lng

- nh lut Bougher-Lampere-Beer: khi chiu mt chm photon n sc qua dung dch th mchp thca dung dch tlthun vi cng sut chm photon v nng cc phn thp th

- Cng thc: A = .l.C2, Cc phng php nghin cua/ Phng php ng chun: quy trnh

- Pha mt lot dung dch chun c Ctc tng dn mt cch u n.(thng 5 8 Ctc) (Cc dung dch chun phi c cng iu kin nhdung dch xc nh)

- Tin hnh o A hoc T ca dy chun chn.- Dng thAX= f(CX). Vit PTHQ tuyn tnh ca ng chun.- Tin hnh pha chdung dch xc nh.- Do A hoc T ca mu.- Cn cvo PTHQ tuyn tnh ca dy chun v AXm xc nh nng ca cht X trong mu

- thA = f(Ctc) tutheo cch o ta thu c 2 dng ng chun:+Dng 1: i qua gc ta + Dng 2: khng i qua gc ta - Khi chn vng nng xy dng ng chun phi ch :+ Vng nng ca dy chun phi bao gm cCX+ Vi vng nng chn dung dch phi tun theo nh lut Beer+ Cc gi trAtcng vi nng chn phi sao cho khi o trn my c lp li cao v bom stuyn tnh A = f(C)

u nhc im ca phng phpu im



12/68



- Vi mt ng chun cho php phn tch hng lot mu.- Dung dch cng khng i hi phi tun theo nh lut Beer mt cch nghim ngt.

Nhc im- chnh xc ca phng php khng cao.

- Khng loi c nh hng ca nn mub/ Phng php so snh

b1- So snh 1 chun- Pha mt dung dch chun c Ctc.- Tin hnh o A hoc T ca dd chun so vi dd so snh (Atc)- Theo nh lut Lambert Beer: Atc= l Ctc.- Pha dung dch mu vi nng cn xc nh CX(cha bit)- Tin hnh o A hoc T ca dd mu so vi dd so snh (AX)- Theo nh lut Lambert Beer: AX= l CX.- Khi dung dch xc nh v dd chun c cng bn cht, c thxem nhnhau, v l = const.

V d:nh lng Pb trong mu thc phm, ta tin hnh cn 5,000 g mu, ho tan thnhdung dch, sau tin hnh to phc vi thuc thdithizon, dng phc Pb ditizon tan trong CHCl3.Tin hnh chit bng CHCl3, dung dch sau khi chit c nh mc thnh 25ml. Dung dch chunc chun btng tnhmu, cha 10 g Pb2+trong thtch dung dch em o l 20,00 ml. Mt quang ca chun v mu = 545 vi l = 1 cm ln lt l Ac= 0,320 v Am= 0,225.

b2- So snh 2 chun- Thc hin kh n gin, hm lng mu tun theo nh lut Beer. Chn cc dung dch chun

sao cho C1


13/68



+ Dng mt dung dch chun v p dng cng thc tnh+ Dng thbiu din

Dng cng thc tnh- Pha mt dung dch c th tch V cha ion cn xc nh c hm lng rt nh. Sau tin hnh

pha 3 dung dch nhsau: STT Bnh 1 Bnh 2 Bnh 3

Dung dch mu VX VX VXDung dch chun C 0 VC 0Thuc thto mu, m pH thm thm khng

- Dng cng thc tnh: xx a(x a ) x

AC C

A A+=

Trong : A(x+a): hp thu ca cc dung dch thmAx: hp thu ca cc dung dch xc nh

Ca: Nng dung dch chun thm vo bnh ng mc 50 mlCx: Nng ca cht X trong dung dch kim tra

V d:Ly 20,00 mL dung dch mu c cha st cho to phc vi thuc ththch hp ri phalong thnh 50,00mL dung dch o. o o hp ca dung dch = 510 nm c gi trA = 0,225 (sdng cuvt c l = 1cm).

Ly 20,00 mL dung dch mu cha st khc thm vo 4 mL dung dch st chun 10 mgFe/L choto phc vi thuc ththch hp ri pha long thnh 50,00mL dung dch o. o o hp ca dung dch= 510 nm c gi trA = 0,358. Tnh nng ppm ca dung dch mu st ban u.Phng php th

- Pha mt dy dung dch chun cng chnh l dungdch nghin cu c cho thm nhng lng chnh xc aica cht cn xc nh nng ca dy chun l CX+Ca1, CX+ Ca2 t nht l 3 dung dch v mt dung dch sosnh.o mt quang A tng ng. Dng thAX+ai Ci

Phm vi ng dng ca phng php thm chun- Phng php thm chun thng c p dng khi nng cht phn tch rt nh(vi lng)

- u im ca phng php thm chun l c thloi c nh hng ca nn mu.- Tuy nhin, chp dng i vi nhng dung dch tun theo nh lut Lambert Beer .My o quang

A

Ax+a3

Ax+a2

Ax+a1

Cx Ca1 Ca2 Ca3



14/68



3, Mt sthuc thhu cdng trong chit trc quanga/ Bromopyrogallol

Cng thc cu to:- Nhm to mui: trong nguyn tH c thcho cation kim loi thay thc to lin kt

ha trl nhm: -OH, -SO3H

- Nhm to phi tr: l nhm OH, = CO,v oxi cn tha 1 cp electron cha lin kt c biudin bng mi tn hoc ng gch t.Danh php: 5,5-Dibromopyrogallol sulfonepththalcin, BPRCng thc phn t: C19H10O10Br2STnh cht ca thuc th: BPR l tinh thdng bt mu sm khi kt hp vi kim loi sng t tantrong nc, acohol v dung mi hu ckhng phn ccPhn ng to phc v tnh cht ca phc cht:

- BPR lin kt vi phenylfluoronl v phc vi mt skim loi to thnh dung dch chelate cmu.

- Khi chelate cng tan trong nc,BPR c sdng nhmt ch thkim loi trong phng

php chun Chelate v nhthuc thca phng php trc quang cho cc kim loi.tinh khit v tinh chthuc th:

- tinh khit ca BPR c thc xc nh bng phng php o quang dung dch ca n:pH: 5,6 7,5 (H2L

2-); max= 558nm; = 5,45.104- Mi trng acid mnh c mu cam,mi trng trung tnh mu , mu tm trong mi

trng kim.- Sphn ly dng acid cho thuc thtng tnhPyrocatechol Violet, v c vit di dng

sau:

NNhhmmmmaannggmmuu

NNhhmmttnng



15/68



ng dng trong phn tch:- L ch thkim loi cho qu trnh chun Chelate ca Bi, Co(II), Ni, Pb. Chng cng c

dng nhchthtrong phng php trc quang i vi mt skim loi nng.- BPR c sdng rng ri nhl mt thuc thphn tch. BPR to thnh phc 3 cu tsm

mu vi 1,10-phenanthroline v bc c sdng cho vic xc nh trc quang bc v Ag gin tipdng xc nh cc anion, nhcc hp cht halogen, cyanide.

- Sdng nhthuc thtrc quang- Sdng nhmt chthkim loi trong phng php chun Chelate:Ion kim loi pH m Mu thay i ti im cui chun

Bi 2 ~ 3 HNO3 sm camCd 10 NH3 NH4Cl Xanh Co (II) 9,3 NH3 NH4Cl Xanh Mg 10 NH3 NH4Cl Xanh Mn (II) 9,3 NH3 NH4Cl Xanh Ni 9,3 NH3 NH4Cl Xanh Pb ~5 AcOH AcONa Tm

t him ~7 AcONa Xanh b/ 1,10 - phenanthroline

CCnnggtthhccccuuttoo--TTnn::1,10 Phenanthroline- ng phn: o -Phenanthroline,4,5 Phenanthroline- Cng thc phn tC12H8N2.H2- Khi lng phn t:198,2

Nguyn liu v phng php tng hp: 1,10 - Phenanthroline c iu chbng cch un nng o-phenylenediamine vi glycerol, nitrobenzene, v H2SO4 c bng phn ng Skraup t 8 -aminoquinolineTnh cht ca thuc th:

- L mt cht bt tinh thmu trng.- Chyu tn ti dng c ngm nc khi nng chy 98 - 100oC do qu trnh mt nc.- Dng khan nng chy 117oC- Dtan trong nc (khong 3,3 g/l nhit phng) v trong benzene (khong 14 g/l nhit

phng). N tan tt trong cn (khong 540 g/l), acetone, v cc acid long.- Thuc thkhng mu v khng c khnng hp thbt kmt tn hiu no vng khkin

Cc phn ng to phc v tnh cht ca phc cht:

NNhhmmttoolliinnkkttpphhiittrr::

NNhhmmmmaannggmmuu

NNhhmmttnnggmmuu



16/68



- 1,10 - Phenanthroline hnh thnh phc c mu bn vi cc kim loi chuyn tip. Tuy nhin,mt shnh thnh cc chelate c cng mu khng mnh bng khi chng tn ti trong dung dchnc. Mt sto chelate gn nhkhng mu. Cu(I) v Fe(II) l cc ngoi lkhi hnh thnh cc vngcng c mu mnh.

Stinh chv qu trnh tinh chha cht:- 1,10 - Phenanthroline c tnh cht ca mt tinh thv ddng c tinh chbng qu trnh kt

tinh li tcc dung mi thch hp, 1,10 - Phenanthroline vn cn cha mt nhm hydrat khi kt tinhli tbenzene nc hay benzene m.

- Chng ta c thkim tra tinh khit mt cch ddng bng cch quan st im nng chycu1,10 - Phenanthroline hoc chun bng acid perchloric trong mi trng acid acetic vi chthnaphtholbenzen.Cc ng dng trong phn tch.Thuc thquang ph: Khi sdng 1,10 - Phenanthroline, phc st mu cam hnh thnh, mtcch inh lng trong khong pH t2 n 9 (tt nht l t4 n 6). Trong cc tc cht thng dng

cht khchuyn Fe(III) vFe(II) th hydroxylamine-HCl v acid ascorbic l c ng dng rngri khong pH ny. Thtcho thm thuc thl rt quan trng, v thtthng c dng l: chtkh, cht ln mu v m.

- hp th tun theo dnh lut Beer trong khong nng t0 - 8ppm Fe v 5 - 50m sttrong 10ml dung dch. bn mu trong khong vi thng.ng dng lm thuc th hunh quang: 1,10 - Phenanthroline thng c dng lm thuc thhunh quang xc nh cc cht nhAg, Cd, Pd, Re, Sc, Zn v t him c hm lng vt. nguyntc ca phng php l da vo sxut hin ca mu hunh quang trong hn hp to phc c hnhthnh khi c mt phi tthhai.ng dng lm cht chit: Phc cation st c bn cao v cc anion khc c thc chit vo pha

hu cnhmt cp ion. Trong cc iu kin thch hp, vic chit rt nh lng, v nng ca aniontng ng trong pha nc c thc xc nh bng cch o cng ca Ferroin pha hu c, theophng trnh sau:

Fe(phen)32+

aq+ 2X-aqFe(phen)3

2+aq+ X22-org



17/68



SQUY TRNH PHN TCH HM LNG BC TRONG THT

II/ Chit hunh quang

- Nhiu hp cht ni phc c bit cc nguyn tnhm II v nhm III ca hthng tun honc kh nng pht hunh quang khi kch thch bng nh sng t ngoi. Cc tnh cht hunh quangthng xut hin trong trng thi rn v trong dung dch, trong s ctrong cc dung mi hu ckhng trn ln vi nc. Da trn csny ngi ta nghin cu cc phng php phn tch chit hunh quang.

- Thng th ngi ta dng hunh quang, tc spht sng ngay trong thi im kch thch, ccphng php tng ng v vy c gi l cc phng php chit hunh quang1,c tnh chung ca phng php

- Cc phng php phn tch da trn schit cc hp cht ni phc v vic o hunh quangtrong dch chit, vphbin v ngha th km hn cc phng php chit trc quang. Tuy nhin

c im quan trng v u vit ca chng so vi phng php chit trc quang l nhy cao hn.Cng c khi nguyn tdng hp cht ni phc c xc nh trong dch chit bng phng phptrc mt nng v bng phng php hunh quang mt nhit khc thp hn. Trng hp ny,v d, c lien quan n 8- oxiquinolinat nhm 8- oxiquinolinatberili.

- Sln nht cc phng php chit- hunh quang trong c dung cc hp cht ni phc cnghin cu cho nhm v gali. Ngi ta cng bit cc phng php i vi Ini, cc nguyn t thim ( Sm, Eu, Tb) Sc, Be, Zn v mt snguyn tkhc. Cc phng php ny c p dng i viAg, Pb, Ti, Cr, Mo, Mn, Fe, Co, Ni.

- Trong cc thuc th chit chelat th 8- oxyquinolin v cc dn xut ca n, c bit 8

oxkhinalin ( 2- metyl-8- oxiquinolin) v 5,7- ibrom-8-oxiquinolin cho nhiu phn ng hunh quang.



18/68



Khnng cho cc hp cht ni phc pht hunh quang gim theo dy: oxiquinolin- iclooxiquinolin-ibromoxiquinolin- iiotaxiquinolin ( thay th trong v tr 5 v 7). Ngoi ra, cc phc hunh quangmnh to c tcc cht nhum ioxiazo- v ioxiazometyl.

- C mt sphng php chittrc quang vi sxdng cc thuc thny t c nghin

cu. Ngoi ra cn bit cc phng php chit cc hp cht ca nhm vi pantokhrom xanh- en P ( 2-oxinaphtalin < lazo- 1>-2- oxinaphtalin 4- sumfoaxit) v vi salixial 2- aminophenol,gali vilumogalion v cc thuc thtng tkhc. Cc phc bc ba gm cc ligan c da trn spht hunhquang cc phc nhvy c nghin cu, v d, i vi cc lantanit.

- C phng php chit hunh quang c mt su im so vi cc phng php hunh quangtrong tng nc cc u im, mc ng ktng tcc u im lu cc phng phpchit- trc quang.

- Khng t cc phng php chit- hunh quang m bo c nhy cao cphp xc nh. Vd, nhy ca php xc nh chit- hunh quang ca gali i vi lumogalion3.5 ln cao hn nhyca php xc nh trong dung dch nc.

- Cng hunh quang tng khi chit cc hp cht ny ca gali vi cc thuc th tng t.Khi chit phc ca km vi 8-(n- toziamino)- quinolin th cng hunh quang cng tng ln, Thtvy,y pht hunh quang ln hn cthuc th.

- Cng c cc v dkhi hunh quang quan st c trong dch chit nhng nhn chung khng ctrong dung dch chit. iu ny cng c lu i vi phc ca gali vi xolokhrom en chit bngru amylic v cc ru khc. Hp cht ca gali vi dn xut ca lumogalion cha trong vtr 5 canhm nitro, cn trong vtr 3- nhm SO3H khng phy hunh quang trong dung dch nc nhng phthunh quang trong ru isoamylic. iu ny c trng i vi cc phc ca gali vi cc thuc thkhc vi nhm nitro trong vtr 5.

- Tuy nhin cng c bit cc trng hp khi c hiu ng ngc li v d: phc ca gali vixolokhrom trong dung dch nc c cng ln hn so vi trong dung dch chit butanol.

- Stng chn lc ca php xc nh c thc m bo bng cch phn chia chit bnhthng cc nguyn tcn xc nh v cn tr.

- Tuy nhin cng xut hin cc hiu ng c o. V d, khi hunh quang trong mi trng ru nc cc phc bc 3 gm samari ( hay europi), tenoiltrifloaxeton v 1,10 phenaltrolin quan stc tc dng lm tt hunh quang ca nguyn tt him khc nhCe, Pr . Sha tan cc phcny trong benzene cho php loi tr tc dng hunh quang. Cng hin tng ny quan st c ivi phc phenantrolin atophan ca europi.

- Thuc thm lng tha ca n c mt trong dch chit c khi tn cng pht hunh quangv lm cn trphp phn tch, v vy trong nhng iu kin nhnhau li hn nn dng cc thuc thchit c yu. tt nhin trng hp c thtch khi lng tha thuc thnhthng lm trong ccphng php chit trc quang ( phng php mt mu trong cc php xc nh vi ithizon )

- Tt nhin, dung mi hu ccng ng vai tr quan trng. Dung mi vnguyn tc khng phthunh quang. Rix quan st thy rng khi xc nh nhm dng 8 oxiquinonlinat th clorofomcng cho mt spht hunh quang ring, khng ln. Spht hunh quang sbgim i do kt quchng ct dung mi. Khi bo quan clorofom chng ct ngay trong bng ti th spht hunhquanglaij tang ln, v vy cp thdng clorofom mi chng ct.



19/68



- Parker lu rng ngi ta cn cha lu y vs lm sch ca dung mi khi cclng vt pht hunh quang. Tc giny lu rng khi o hunh quang trong cc dung dch rtlong th hiu ng tn xthp ca nh sang ( hiu ng Raman ) cng gy hiu ng ng k. Hiung Raman gy ra bi cc phn t ca dung mi. T nhiu dung mi nhn c ( nc, etanol,

xiclohecxan, CCl4, CHCl3) khi kch thch bng nh sang n thy nhn vi cc di song 284, 313,365 v 436 nm th clorofom cho hiu ng Raman nhnht.Tuy nhin, quan trng hn l nh hng ca dung mi ln nh sang v c bit ln cng hunhquang gy ra bi stng tc ca cc phn tdung mi v cht tan.

- Ni chung cn nhn mnh rng : cng nhtrong tt ccc phng php da trn schit cchp cht ni phc, nh hng cu dung mi trong cc php xc nh chit hunh quang lun lunphi tnh n vic chn dung mi theo quan im chit c honh ton nguyn t.

- Hin tng cui cng ny ddawcjj bit ng ki vi cc hp cht ni phc to c bi cccht nhum dioxxiazo v dioxxiazo metyl cha mt nhm sunfo. Nh ni trn, trong trnghp ny khng t khi to c cc phc thy phn mnh, tch in. chit chng c thdng ch ca

cc dung mi hot ng phi tr c bit l cc ru. Tt ccc phng php chit hunh quang m ttrong ti liu ( c lien quan n vic dng cc cht nhum ny ) u da trn vic sdng cru. Tt nhin, cc phng php hunh quang mu khc trong c dng cc thuc thny c thchuyn sang cch chit nu nhdng cc ru lm cc dung mi ( v dtru n butanol cho n n- hecxanol ).

- Cng nhcc phng php chit trc quang, xc nh mt vi nguyn tc thdng schit lin tc cc gi trpH khc nhau, cc cht che

- m t php xc nh hunh quang trong cc hm lng tng ng ca gali, ini vBeridi nh8- oxikhinanin da trn schit lin tc bng clorofom pH = 3,9 ( gali ), pH = 5,5 ( Ini

), pH = 8,1 ( Berili )- Khollat v Rodier xc nh ng thi nhm v gali trong hn hp ca 8 oxiquinonlinatca chng. Ngi ta chit chai nguyn tpH = 5,7 bng clorofom v o hunh quang cc bcsng khc nhau ca bc xkch thch : 365 v 436 nm

- Ngi ta cng thnh cng trong vic xc nh c mt cch tha mn cc nguyn tmc duc sging nhau vcc phhunh quang ca chng.2, Cc v dsdng phng php:

- Nh lu cc phn ng hunh quang c trng cho cc nguyn tnhom II v c bitnhm III ca hthng tun hon.

- Cc phng php chit hunh quang xc nh nhm ch yu da trn vic dng 8

oxiquinolin. Trong dch chit clorofom (pH (7 9)) th axiquinonlinat nhm c hunh quang muvng v xanh. Phng php ny sdng rng ri trong phng thc hnh ha phn tch.V d: cc phng php xc nh nhm trong bia, nc thin nhin, magie, kim loi, vonfram

v oxit vonfram, oxitthri v cc i tng khc. Hunh quang mnh quan st c khi chit bngtetraclorua cacbon.

- Mt vi phng php hunh quang st nh nhm da trn vic chit cc phc ca n vi cccht nhum oxiazo v oxiazometyl. Pantakhrm mu xanh en P (khrm axit xanh en, eriocrmxanh en B (1) to c vi nhm hp cht chit quang c pH 4,5 5,6 bng ru amylic. Phcpht quang vi xalixial 2 amiophenol c chit bng ru izoamylic tdung dch nc c boha bng axetat natri:



20/68



(1)

- i vi php xc nh chit quang gali ngi ta dng schit phc 8 oxiquinonlinat can bng clorofom pH = 2,6 3,1. Phng php ny do Xendel ngh. Sau phng php nyc chnh xc ha v c dng xc nh gali trong cc bxit v cc i tng khc. Phc phthunh quang trong tetraclorua cacbon.

- Cc nh nghin cu Nht Bn dng vic chit hp cht ni phc ca gali vi 8 oxikhinalin (pH = 3,9; hunh quang mu xanh ca dch chit clorofom). Nhphng php ny ngita xc nh 0,002 0,001% gali trong cc qung xilicat v gecmani kim loi (Ge). Schit ca ccphc gali vi 5,7 iralondo thay thca 8 oxiquinolin c dng khi xc nh nguyn tnytrong cc hp kim ca nhm.

- Cng nhi vi nhm, i vi gali ngi ta nghin cu cc phng php c dng hpcht oxiazo. pH = 4,7 gali c chit bng ru amylic dng phc vi Xolokhrm en v phthunh quang ngay cdi tc dng ca nh sng ban ngy. Hp cht c chit bng ru butanol vru gexilic nhng cng hunh quang trong cc dung mi ny thp hn trong ru amylic.Phng php rt nhy xc nh gali da trn vic sdng lumogalion hp cht ni phc to ra chitc pH = 2,2 bng ru ioamylic. nhy ca spht hin cht hunh quang gali l 10-4g/ml.

- M tphng php xc nh hunh quang gali, cupheron v morin. Hp cht ny c chitbng clorofom. Phng php c dng xc nh gali trong cc khong vt nc v cc qung st, nhy t 0,2 1,0g/ml ca clorofom. Dch chit benzen ca 8 mercaptoquinonlinat gali pht

hunh quang (chit pH = 5, nhy 0,11g/ml). Dng ru izoamylic pH = 3,6 ngi ta chitphc hunh quang ca gali vi Kxetin; nhy ca php xc nh 0,05g/ml.

- xc nh chit hunh quang ini c th dng 8 oxiquinolin, 8 oxikhinalddin, 8 mercaptoquinolin. - 8 oxiquinolin cho phn ng hunh quang vi Scani. Ngi ta tin hnh chit pH = 7 bng clorofom. Php xc nh t1 30g Scani khng cn tr100g cc nguyn tthim. lm dung mi dng ru izoamylic, n-butilic v tetraclorua cacbon nhng cng lnnht ca hunh quang v bn ca n theo thi gian c m bo nu dng cloroform. Dng 8-oxiquinonlin ngi ta cng c thxc nh Ytri.

- xc nh europi v terbi dng phng php chit hunh quang bao gm schit bngbenzen ca phc bc ba c to bi nguyn taxit salixilic v 1,10-phenantrolin. Axit Salixilic thc

tkhng c chit v khng cn trphp xc nh. iu th vl mc chit phthuc vo nngnguyn t. Khi trong pha nc c t hn 100g oxit ca nguyn tth mc chit bgim i, vvy trit tiu, ngi ta thm mt nguyn tt him khc, v dLantan hay iprozi, cc nguyn tny chit c nhng li khng pht hunh quang trong dch chit. Theo cc d liu ca oklae,thnh phn ca phc tng ng vi cng thc MA3.(ph)2, y A- gc ca axit salixilic, ph-phenantrolin.

- xc nh samari, europi ngi ta dng phng php tng tnhng thay cho axit salixilic dng tenoiltrifloaxeton. Dng phng php hng phn tgam tm c rng cc phc chitc c thnh phn MA3ph. nhy xc nh trong hn hp oxit cc nguyn tt him bng 0,05%

OH HO

N = SO3H



21/68



i vi samari v 0,002% i vi europi. Phng php ny c dng xc nh 5.10-35.10-4%europi trong oxit lantan.

- Cc phng php chit hunh quang cng c dng xc nh cc nguyn tnhm hai cahthng tun hon, c bit l berili, magie v km. Berili c thxc nh dng 8-oxiquiolinat, phc

ny chit c bng metylizobutylxeton tdung dch tactrat pH=9,2. Ngi ta lu rng s tngnhit t22oC n 26oC gy ra sgim khng thun nghch cng hunh quang v sthay ica dch chit tmu vng sng n mu nu.

- Quan st c hunh quang mnh ca dch chit ca oxiquinonlinat berili trong tetracloruacacbon. Tt nhin, phng php xc nh berili vi 8-oxiquinonlin l bch v rng nhm khng tngtc vi thuc thny. 8-oxikhinalinat c thchit c pH (8 0,2) bng cloroform; khi chiu dchchit bng nh sng tngoi xut hin hunh quang mu vng xanh. Lng tha thuc thgy nhhng cn tr. Xoloviev v Bojevolnov nghin cu phng php xc nh berili vi ibenzoil metalda trn vic o ln quang dch chit trong tetraclorua cacbon. Ngi ta o ln quang nhit nitlng. Phng php xc nh berili trong nc thi, nhy 2.10-6%

- Ngi ta xc nh km dng 8-oxiquinonlinat (chit bng metylizobutylketon pH cao hn9,4) v dng 8-mercapto quinolinat (chit bng benzen pH=5; nhy 0,01g/ml). Phng phpcui c dng xc nh km trong cc hp kim ca nhm v magi. Bojevolnov v cc tc gikhc nghin cu phng php xc nh km v caimi vi 8-(n-tozinamino)-quinonlin. Cc phcc chit pH (8,0 8,3) v kch thch bng nh sng tngoi cho c hunh quang mu xanh.Phng php ny c p dng xc nh km trong tetraclorua gecmani v trong tricloxan.

III- Chit hp th, pht x, hunh quang nguyn t1, Chit hp thnguyn t

Ngi ta dng vic chit cc hp cht ni phc trong php o phhp thnguyn t.Theo cc dkin ca egnal Uect th php chit 8-oxiquinonlinat ch bng metylzobutyxeton hay

itylithiocacbaminat bng etylaxetat vi php trc quang tip tc cc dch chit cho php lm tng nhy ca cc php xc nh ca nguyn tny so vi php phn tch dung dch nc tng ng tbav chn ln.

- Pomitrek v Maliss nghin cu cc phc ca mt skim loi vi pyroliinithiocacbaminatamino, 8-oxiquinonlin, ithizoncupheron v axetylaxetat. lm dung mi h dng clorofom,tetraclorua cacbon, toluel, etylaxetat , metylzobutylxeton.

- Cc thc nghim chra rng sphun bi trc tip cc dch chit trong ngn la oxi hidro cngcho php tng nhy ca cc php xc nh.

- Cc php xc nh c n gin ng kcng nhtrong php trc quang dng ngn la, khngcn phi lm bay hi trc cc dung dch v ph hy cc dch chit.c/ S xut hin phhp thnguyn tv nh lut cbn

- Bnh thng, nguyn ttrng thi cbn, bn vng mc nng lng thp- Khi cc nguyn ttrng thi tdo trong mt m hi,- Nu chiu chm bc xc bc sng xc nh ng vi bc sng m chng c thpht ra

khi trng thi kch thch vo m hi nguyn ttdo ,- Nguyn t hp thbc xchiu vo . l qu trnh hp thnng lng ca nguyn ttdo

trng thi hi to ra phhp thnguyn tca nguyn t.- A phthuc vo snguyn tN trong mi trng hp th: A = k.N trong k l hsthc

nghim, phthuc vo bn cht nguyn t, nhit ca mi trng hp thv bdy ca lp hp th.



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- Gia snguyn tN vi nng C ca nguyn t trong mu phn tch c biu thbngbiu thc: N = kiC

btrong ki, l hng sthc nghim, b c gi l hng sbn cht, n phthucvo nguyn tv bc sng ca dng sng, b c ga tr1; b = 1 khi nng C nh.

- Kt hp cc biu thc trn ta c: A = aCb trong a l hng s thc nghim. ng vi mi

bc sng, mi nguyn tc mt ga trC = C0l gii hn, khi nng C nhhn nng ngng C0th b = 1- Phng trnh biu din mi lin quan gia hp thA v nng C l nh lut cbn ca

php o phhp thnguyn t: A = aC

e, Cc u nhc im ca php o phhp thnguyn tCc u im

- Php o phhp thnguyn tc nhy v chn lc cao. Trn 60 nguyn tha hc c thxc nh c bng phng php ny vi nhy t104105. c tht ti n.107%. vi k thutkhng ngn la, nhy

- iu kin thc nghim tng i d, c thcho tt ccc phng th nghim nhv va.- C thxc nh ng thi hay lin tip nhiu nguyn ttrong cng mt mu.- Kt quphn tch n nh, sai snh.

Nhc im

SMYQUANG

PHHPTHNGUYNTMT

CHM TIAV HAI

CHM TIA



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- Chcho ta bit thnh phn nguyn tca cht phn tch c trong mu phn tch, m khng chrac trng thi lin kt, cu trc ca nguyn t.

f, ng dng phng php phn tch phhp thnguyn t- Phng php quang phphhp thnguyn tdung phn tch vt cc kim loi trong cc loi

mu khc nhau ca cc cht v cv hu c(khong trn 60 nguyn t l cc kim loi trong qung,t , nc khong, cc mu y hc, sinh hc, cc sn phm nng nghip, rau qu, thc phm, ncung, cc nguyn tvi lng trong phn bn, trong thc n gia sc).

- Phng php phn tch phhp thnguyn t cng c dng xc nh mt sphi kim nhSi, P, As, Te, Se. Mt sphi kim c thphn tch gin tip qua kim loi.2, Chit pht xnguyn ta- Sxut hin phpht x

- Trong iu kin bnh thng, cc in tchuyn ng trn cc quo ng vi mc nng lngthp nht. Khi nguyn ttrng thi bn vng, trng thi cbn.

- trng thi ny nguyn tkhng thu v cng khng pht nng lng. Nhng nu cungcp nnglng cho nguyn tth trng thi khng tn ti na. Theo quan im ca thuyt lng t, khi trng thi kh, in tchuyn ng trong khng gian ca nguyn t, c bit l cc in tha tr, nuchng nhn c nng lng bn ngoi (in nng, nhit nng, ha nng,...) th in tschuyn lnmc nng lng cao hn. Khi nguyn t bkch thch. N tn ti trng thi kch thch. Nhngtrng thi ny khng bn vng. Nguyn tchlu li trng thi ny nhiu nht l 10 8 giy. Sau n lun lun c xu hng trvtrng thi cbn ban u bn vng. Ngha l gii phng nng lngm chng hp thc trong qu trnh trn di dng ca cc bc xquang hc. Bc xny chnhl phpht xca nguyn t, n c tn sc tnh theo cng thc:

E = (En E0) = hv (1.1)

hay: Ehc

E =

Trong :+ Env E0l nng lng ca nguyn ttrng thi cbn v trng thi kch thch n; h l hng

sPlank (6,626.10-7erk.s) hay h = 4,1.10-15eV.s;+ c l tc nh sng (3.108m/gy) - 2,99793.108m/gy; v l tn sca bc x;+ l bc sng ca bc x.- Trong biu thc trn, nu gi trE l nm ta c qu trnh hp thv khi gi trE dng ta c

qu trnh pht xca nguyn t.- Nhng trong nguyn t, schuyn mc ca in t tmc nng lng Enkhng phi chv

mc E0, m c rt nhiu schuyn mc tEnvcc mc khc E01, E02, E03cng vi mc E0. Nghal c rt nhiu schuyn mc ca in t c lng tha, v ng vi mi bc chuyn mc ta c 1 tia bc x, tc l mt vch ph.

- Chnh v thm mt nguyn tkhi bkch thch thng c thpht ra rt nhiu vch phphtx. Nguyn tno c nhiu in tv c cu to phc tp ca cc lp in tha trth cng c nhiuvch phpht x.

- Nu dng my quang phthu chm ra pht x, phn li v ghi li cc chm tia pht xdonguyn tpht ra ta sc mt di phtsng ngn n sng di. l phpht xca nguyn tca cc nguyn tv n l phvch.Nhvy, phphtxnguyn tl sn phm sinh ra do stngtc vt cht, m y l cc nguyn ttdo trng thi kh vi mt ngun nng lng nhit, in...nht nh ph hp.

- Nhng trong ngun sng, khng phi chc nguyn ttdo bkch thch, m c cIon, phn



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t, nhm phn t. Cc phn tny cng bkch thch v pht ra phpht xca n. Tt nhin l trongmc khc nhau ty thuc vo khnng kch thch ca ngun nng lng. V vy, phpht xcavt mu lun bao gm ba thnh phn:

Nhm phvch. l phca nguyn tv con. Nhm phvch ny cacc nguyn t

ha hc hu nhthng nm trong vng pht190-1000nm (vng UV-VIS). Chc mt vi nguynt kim hay kim loi kim mi c mt svch phnm ngoi vng ny.Nhm phm. l phpht xca cc phn tv nhm phn t. V dphca phn t

MeO, CO v nhm phn tCN. Cc m phny xut hin thng c mt u m v mt u nht.u m pha sng di v nht pha sng ngn. Trong vng tngoi th phny xut hin rt yuv nhiu khi khng thy. Nhng trong vng khkin th xut hin rt m, v lm kh khn cho phpphn tch quang phv nhiu vch phn tch ca cc nguyn tkhc bcc m phny che lp.

Phnn lin tc.y l phca vt rn bt nng pht ra, phca nh sngtrng v phdosbc xring ca in t. Phny to thnh mt nn mlin tc trn ton di phca mu. Nhngnht sng ngn v m dn vpha sng di. Phny nu qu m th cng scn trphp phntch.

- Ba loi phtrn xut hin ng thi khi kch thch mu phn tch v trong phn tch quang phpht xnguyn tngi ta phi tm cch loi bt phm v phnn. l hai yu tnhiu.b, Nguyn tc ca php o phpht x(AES): Tvic nghin cu nguyn nhn xut hin phpht x,chng ta c thkhi qut phng php phn tch da trn cso phpht xca nguyn tphi baogm cc bc nhsau:

- Trc ht mu phn tch cn c chuyn thnh hi (kh) ca nguyn thay Ion tdo trongmi trng kch thch. l qu trnh ha hi v nguyn tha mu. Sau dng ngun nng lngph hp kch thch m hi chng pht x. y l qu trnh kch thch phca mu.

- Thu, phn 1i v ghi ton bphpht xca vt mu nhmy quang ph. Trc y, phcghi ln knh nh hay phim nh. Chnh my quang phslm nhim vny. Nhng nhng trang bhin

i ngy nay c ththu v ghi trc tip cc tn hiu cng pht xca mt vch phdi dng cclc trn bng giy hay chra cc sng cng vch phtrn my in (printer), ghi li vo a tcamy tnh.

- nh gi ph ghi vmt nh tnh v nh lng theo nhng yu cu t ra. y l cngvic cui cng ca php o.

- Chnh v vy, ng vi cc nhim vv nguyn tc ny, thc hin mt php phn tch datheo phpht xca nguyn tngi ta phi cn mt hthng trang bcng gm ba phn tng ngnhth.c, Qu trnh kch thch phtrong ngn la

- Trong phn tch quang phpht x, nu dng ngn la lm ngun kch thch th mu phn tch

phi chun bdng dung dch. Sau nhmt hthng phun (Nebulizer system) a dung dchny vo ngn la di dng thsng m (thsi kh - aersol) cng vi hn hp kh t. Khi vongn la, di tc dng ca nhit , trc ht dung mi bay hi, li cc ht bt mu mn ca cccht phn tch, ri n c t nng v chuyn thnh hi ca nguyn tv phn t. Trong ngn lacc phn thi ny chuyn ng, va chm vo nhau, trao i nng lng cho nhau,... Kt quca ccqu trnh lm cc phn tbphn li thnh nguyn t, bIon ha v bkch thch. Nhvy trongngn la tn ti cnguyn ttdo, phn t, Ion, nhm phn tv cc in t. Trong tp hp ch

yu chcc nguyn ttdobkch thch v pht x. V thphpht xngn la l phca nguyn ttrung ha. Nguyn nhn gy ra skch thch phy l sva chm ca cc nguyn tvi cc in tc ng nng ln trong ngn la. V thnhit ngn la cng cao th cc in t c ng nng



25/68



cng ln. V thn l skch thch nhit. Do cchca qu trnh kch thch trong ngn la l:Trc ht l dung mi bay hi,li cc ht mudng bt. Tip theo lbt mu bnung

nng, nng chy. Sau l cc qu trnh nhit ha ca cht mu xy ra theo tnh cht ca n, v gmc hai qu trnh chnh:

Nu Eh< Entth mu sha hi, nguyn tha to ra cc nguyn ttdo,chng bkch thchv pht xcphpht x(AES).MenXm(r).Th. MenXm(k) mMe(k) +nX(k) Me(k) +E Me(k)

*Me O+n(Hv)Nng lng K Chm tia pht x

Cchny (cch1) cho nhy v n nh cao ca spht x. Cc hp cht mui halogen(trF), axetat, mt snitrat, sunphat... ca kim loi thng theo cchny.

Nu Eh> Ent th mu sbnguyn tha trc, sau ha hi thnh nguyn t, ri bkchthch phsinh ra phpht x(AES).

MenXm(r) Mn(r) +Xm(r) mMe(k) +nX(k) Me(k) +E Me(k)*Me O+n(Hv)

Nng lng K.Th. Chm tia pht xCchny (cch2) cho nhy v n nh km so vi cch1 ca spht x.Cc hp cht mui SIO2-3, PO3-4, F-, mt snitrat, sunphat,.. ca kim loi thng theo cchny.Do c im ca 2 cchchnh , nn trong phn tch ngi ta thng to iu kin skch

thch phxy ra theo cch1 c li. iu gii thch ti sao ngi ta hay dng cc mui halogen, vaxetat ca kim loi kim lm nn, hay cht phgia cho mu phn tch.d,i tng ca phng php phn tch phpht x

- Bn cnh mc ch nghin cu vt l quang phnguyn t, php o phpht xnguyn t lmt phng php phn tch vt l da trn tnh cht pht xca nguyn ttrng thi hi xc nhthnh phn ha hc ca cc nguyn t, cc cht trong mu phn tch. V vy n c tnphn tch quang

phha hc.Phng php ny c sdng phn tch nh tnh v nh lng cc nguyn thahc, chyu l cc kim loi trong mi i tng mu khc nhau, nha cht, ha hc, luyn kim, ha

du, nng nghip, thc phm, y dc, mi trng... thuc cc loi mu rn, mu dung dch, mu bt,mu qung, mu kh. Tuy phn tch nhiu i tng, nhng thc cht lxcnh cc kim loi l chnh,ngha l cc nguyn tc phpht xnhy, khic kchthch bng mt ngun nng lng thch hp;sau l mt vi kim nhSi, P, C. V vy, i tng chnh ca phng php phn tchda theo

phpo phpht xcanguyn tl cc kim loi nng nhtrong cc loi mu khc nhau. Viitng kim th phng php ny c nhiu nhc im v hn chvnhy, cng nhnhng trangbthu, ghi phca chng, v phca hu ht cc kim li nm ngoi vng tngoi v khkin,ngha l phi c thm nhng trang bphc tp mi c thphn tch c cc kim.e, Cc u im v nhc im

- Phng php phn tch quang phpht xnguyn tsdc pht trin rt nhanh v c s

dng trong nhiu lnh vc ca khoa hc, kthut cng nghip, nng nghip v i sng v n c nhngu im rt cbn:

+ Phng php ny c nhy rt cao. Bng phng php ny nhiu nguyn tcthc xcnh t n nhy tn.103n n.104%. Nhng vi nhng trang bhin i v vi nhng ngunkch thch phmi (ICP) ngi ta c tht n nhy tn.10-5n n.10-6% i. Vi nhiu nguyntm khng cn phi lm giu mu phn tch (bng 1). V thn l phng php kim tra, nh gitinh khit ca nhiu ha cht v nguyn liu tinh khit cao, phn tch lng vt cc kim loi nngc hi trong i tng thc phm, nc gii kht, mi trng. Trong khi vi nhng i tng nyth phng php ha hc khng thno t c.

+ Phng php ny gip chng ta c thtin hnh phn tch ng thi nhiu nguyn ttrong mt



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mu, m khng cn tch ring chng ra khi nhau. Mt khc, li khng tn nhiu thi gian, c bit lphn tch nh tnh v bn nh lng.

+ Vi nhng tin bca kthut hin nay v vi nhng trang bhin nay t c, th phngphp phn tch theo phpht xnguyn tl mt php o chnh xc tng i cao. Trong nhiu trng

hp, vi nng nh(cppm) m sai sca php o l di 10%. Tt nhin vi nhng trang bvmy mc cin th sai sc thln hn. Song thc tn bnhng trang bhin i y li.+ Phng php phn tch theo phpht xl mt phng php phn tch tiu tn t mu, chcn

t1 n vi chc miligam mu l . c bit l kthut phpht x.+ Phng php phn tch ny c thkim tra c ng nht v thnh phn ca vt mu

nhng vtr (ch) khc nhau. V thcng c ng dng kim tra ng nht ca bmt vt liu.+ Trong nhiu trng hp, phca mu nghin cu thng c ghi li trn phim nh, knh nh

hay trn bng giy. N l nhng ti liu lu trv khi cn thit c thnh gi hay xem xt li mkhng cn phi c mu phn tch.

- Bn cnh nhng u im nu, phng php ny cng c mt snhc im v hn chnhtnh. Trc ht phi ni n l: Phng php ny chcho chng ta bit c thnh phn nguyn tcamu phn tch, m khng chra c trng thi lin kt ca n trong mu. chnh xc ca phpphn tch phthuc vo nng chnh xc ca thnh phn ca dy mu u v cc kt qunh lngu phi da theo cc ng chun ca cc dy mu u c chto sn trc.

Mc du c mt snhc im v hn ch, nhng phng php phn tch quang phpht xnguyn tngy cng c pht trin v ng dng rng ri trong nhiu lnh vc khc nhau xc nhlng vt cc nguyn ttrong cc i tng mu khc nhau. l mt phng php phn tch nhanh,c chnh xc bo m v nhy kh cao, c bit thch hp cho phn tch t him, cc loi nc,khng kh, v.v.

f, Khnng v phm vi ng dng- Phng php phn tch quang phpht xnguyn tngy nay givai tr quan trng trong ha

hc phn tch. Cng vi spht trin mnh mca cc ngnh khoa hc kthut, c bit l vt l vha hc, spht trin ca k thut o v ghi tn hiu, lm tng khnng ng dng to ln ca n.Bng phng php ny ngi ta c thxc nh nh tnh, bn nh lng v nh lng c hn nmchc kim loi v gn mt chc nguyn t kim trong cc i tng mu khc nhau (v cv hu c).Phng php phn tch ny trthnh cng cphn tch nguyn tc lc ch nhiu lnh vc, nhtl sau khi c ngun kch thch ICP.

Phn tch quang phpht xtrong ngnh ha v cng nghip ha hc. N lcng cccnh ha hc xc nh thnh phn nh tnh v nh lng ca nhiu cht, kim tra tinh khit ca ccha phm, nguyn liu v nh gi cht lng ca chng. N cng l mt phng php xc nh ccng vphng xv nghin cu cu trc nguyn t.

Phn tch quang phpht xnguyn ttrong a cht. Ngay tkhi mi rai, phng phpny c cc nh a cht sdng phn tch cc mu qung phc vcho cng vic thm d a chtv tm ti nguyn khong sn. V thngnh a cht ca tt ccc nc u c phng phn tch quangphpht xrt hin i v hon chnh.

Phn tch quang ph pht x trong luyn kim. Luyn kim cng l mt ngnh s dngphng php phn tch quang phpht xu tin vo mc ch ca mnh trc cngnh ha. Chnhtnh cht nhanh chng v nhy ca phng php ny l mt iu rt cn thit i vi ngnh luynkim. N c thl cng cgip cc nh luyn kim xc nh ngay c thnh phn ca cc cht angnng chy trong l luyn kim; qua m hc thiu chnh nguyn liu a vo chto cnhng hp kim c thnh phn mong mun, kim tra thnh phn, kim tra nguyn liu.



27/68


28/68



nguyn tcng nhthnh phn. Kthut EDX c pht trin tnhng nm 1960s v thit bthngphm xut hin vo u nhng nm1970s vi vic sdng detector dch chuyn Si, Li hoc Ge[2].

Kthut ghi nhn v chnh xc ca EDXTia X pht ra tvt rn (do tng tc vi chm in t) sc nng lng bin thin trong di rng, sc a n h tn sc v ghi nhn (nng lng) nhdetector dch chuyn (thng l Si, Ge, Li...)c lm lnh bng nitlng, l mt con chip nh to ra in t thcp do tng tc vi tia X, ri

c li vo mt ant nh. Cng tia X tlvi tphn nguyn tc mt trong mu. phn giica php phn tch phthuc vo kch cchm in tv nhy ca detector (vng hot ng tchcc ca detector).chnh xc ca EDX cp mt vi phn trm (thng thng ghi nhn c sc mt ca ccnguyn tc tphn c3-5% trln). Tuy nhin, EDX tra khng hiu quvi cc nguyn tnh(vdB, C...) v thng xut hin hiu ng trng chp cc nh tia X ca cc nguyn tkhc nhau (mtnguyn tthng pht ra nhiu nh c trng K, K..., v cc nh ca cc nguyn tkhc nhau cthchng chp ln nhau gy kh khn cho phn tch).

Phtn sc nng lng tia X mu mng mng, ghi nhn trn knh hin vi in ttruyn qua FEITecnai TF20.

Nhng bin thca EDX



29/68



Phin tAuger(Auger Electron Spectroscopy (AES)): thay v pht ra cc tia X c trng,khi cc in tc nng lng ln tng tc vi lp in tsu bn trong skhin mt sin tlppha ngoi bbt ra to ra phAES.

Phhunh quang tia X(X-ray Photoelectron Spectroscopy (XPS)): tng tc gia in tv

cht rn gy pht ra phhunh quang ca tia X, c thm cc thng tin vnng lng lin kt.Ph tn sc bc sng tia X(Wavelength-Dispersive X-ray Spectroscopy (WDS)): tng tnhphEDX nhng c tinh cao hn, c thm thng tin vcc nguyn tnh, nhng li c khnng loi nhiu tt hn EDS v chphn tch c mt nguyn tcho mt ln ghi ph.4, Chit ho phng x

- Phng php da trn syu dn ca tia gamma xut pht tmt ngun gamma (thng u d di ng) do nh hng ca tn xCompton v hp thin-quang. Cng ca tia gammakhi ti u thu (thng c gn cnh bn y ca my) tlthun vi mt in t. Tng tcgia tia gamma v nguyn tvt liu cng mnh th vt liu bchiu tia cng c chc. iu ny cho tabit khi lng thtch tnhin ca t thng qua vic xc nh cng tia gamma khi truyn quami trng t trn csso snh vi mt biu gi trchun thch hp.

- Theo nguyn tc ny, c hai cch o khi lng thtch tnhin:Phng php phng xtruyn trc tip:+ Ngun tia gamma c gn u d di ng v c a xung di su vo vtr cn o.+ u thu tia gamma c gn cnh vo bn y ca my.+ Tia gam ma thu c u thu tngun pht sau khi i qua mi trng vt liu cn o.

Hnh 4.1 Snguyn l o truyn trc tip Hnh 4.2 Snguyn l o tn xngc

Phng php tn xngc:+ Ngun tia gamma c gn u d thng t vtr di bn y ca my.+ u thu tia gamma c gn cnh vo bn y ca my.+ Tia gam ma thu c u thu tngun pht sau khi i vo mi trng vt liu cn o

v tn xngc trli bmt tip xc gia mi trng cn o v my.V d:Ti liu nh km theo bi

B/ Phc cht dng tch bng phng php sc k



30/68



I- Vi nt lch s:- Phng php sc k c pht trin vo nm 1903 do nh thc vt hoc ngi Nga Michael

C.Txvet.ng thc sl ngi u tin c cng tm ra phng php, gii quyt vn tch cc cht ctnh cht ging nhau theo mt cchc o, hon ton khc vi phng php tch tng c trc

y, tuy nhin pht hin ny blng qun nhiu nm.- Nm 1941, Martin v Synge pht trin sc k phn btrn giy v a ra l thuyt a gii thch cc qu trnh sc k, cc tc gi ng dng tch cc ancaloit tcc cy thuc phc vcho chto dc phm. Do c cng trong vic pht trin l thuyt ca phng php cho nn nm 1952hai ng c nhn gii thng Nobel vho hc.

- Cng tnm 1952 nhng my sc k mi ra i tra c u thdo c hiu qutch rt cao.Ct mao qun v cc detect sau ny c ci tin tng phn gii v nhy ca phng phpngi ta c thphn tch c cc cht c hm lng nhcppm v ppb. Ty phng php cpht trin nhanh, ng dng c nhiu trong thc t.

- Vsc k lng mt kthut mi c pht hin tnm 1970 lm tng hiu qutch l sck lng hiu nng cao (high performance lipuid chromatography- HPLC): Cht nhi ct c ci tin,my tnh v thit bvo btrc a vo, tng cng khnng ca phng php.

- Ngy nay kthut ghp ni gia sc k v cc phng php khc c p dng. l kthutghp ni gia sc k v khi ph( GC-MS, GC-MS) sc k v cng hng ht nhn, sc k a chiu,sc k in mao qun(CEC)... Phng php c chnh xc v nhy rt cao, phn tch c nhiui tng phc tp hn.II- Phn loi Nguyn tc:1,nh ngha:

- Sc k l qu trnh tch da trn sphn blin tc cc cu tcht phn tch trn hai pha: mtpha thng ng yn c khnng hp thcht phn tch gi l pha tnh, mt pha di chuyn qua phatnh gi lpha ng; do cc cu tcht phn tch c i lc khc nhau vi pha tnh, chng di chuyn vi

tc khc nhau v tch ra khi nhau.2, Phn loi cc phng php tch sc ka/ Phn loi theo hpha

Phng php u tin c nhiu ngi quan tm, y l phng php phn loi n gin theohpha tc l cht phn tch phn bgia hai pha l g?

Sphn loi cc phng php sc k

hpha

Cch



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b/ Phn loi theo cchtch:

b1- Sc k hp th:- Sc kh hp th l phng php da trn csphn bcht phn tch gia pha tnh v phang nhtng tc phn tthng qua cc trung tm hp th. Pha tnh l cc cht rn hoc lng c dintch bmt ln, bn vng vmt ho hc. Chng hp thcht phn tch trn bmt ca chng ccmc khc nhau khi cho pha ng cha cht phn tch tip xa vi chng. Tu thuc lc lin ktgia pha tnh v tng cu tcht phn tch c trong pha ng, khi cho pha ng i qua pha tnh chngsdi chuyn vi tc khc nhau.

b2- Sc k phn blng - lng- Sphn bit gia sc k phn blng-lng v sphn bthng thng l chsc k phn

blng - lng cn c gi l sc k chit, pha tnh l cht lng pha ng cng l cht lng, sphnbcht phn tch gia hai pha lng ging nhqu trnh chit, cn sphn bni chung l sphn chiacht phn tch vo hai pha khng cn xt ti lng hay rn.

- im khc nhau cbn gia sc k phn b lng - lng v sc k hp ph l ch: sc kphn b lng- lng c ng ng nhit tuyn tnh khong nhit ln, phng php c nhycao nhng c nhc im l pha tnh khng c bn vng, hin tng tri mt pha tnh lm cho lp li bgim.

b3- Sc k ion ( trao i ion)- Pha tnh thng l pha rn c khnng trao i ion ca n vi cc cht phn tch trong pha

ng.Cht c kh nng trao i cation gi l cationit, cn cht c kh nng trao i anion gi lanionit. Lc lin kt chyu gia cht phn tch v pha tnh chyu l lin kt tnh in , phthucnhiu vo in tch ca ion cht phn tch, pH ca dung dch v bn knh hidrat ho ca cc ion cht

phn tch.V d: phn ng trao i ion gia cationit acid mnh v Ca2+ c th vit nh sau:

2R-SO3H + Ca2+ = (R-SO3)Ca + 2H

+phn ng ca anionit bazmnh vi Cl-:R-N(CH3)3OH + Cl

- = R-N(CH3)3Cl + OH

-b4- Sc k ry phn t(sc k loi c)- Pha tnh l cc cht rn c din tch bmt ln, xp, c nhng ng i trong lng cht rn,

cn gi l mao qun c kch thc cphn t. Cc phn tcht phn tch c ththm vo cht mc khc nhau tutheo kch thc ca chng. Cc cht phn tch c kch thc ln khng thivo su vo pha tnh c, sbra gii nhanh cn cc phn tcht phn tch c kch thc nhphnb su vo pha tnh sb ra gii chm. Th t ra gii l cc cht c kich thc nhi ra sau v

ngc li. Thi gian lu ca cc cht tlnghch vi kch thc phn tca chng. Tuy nhin chtphn tch c thc tng tc khc vi pha tnh. Nhvy mt php sc k c th tch theo mt haynhiu cchkhc nhau m chng ta khng xt y.c/ Phn loi theo cch hnh thnh sc

c1- Phn tch tin lu- Cc cu tA, B, C c i lc vi pha tnh l A < B< C. Cho hn hp cht phn tch lin tc i

qua ct, cht phn tch c i lc vi pha tnh thp nht i trc, tip theo l cht c i lc yu hn. Tuynhin do chng ta cho lin tc cht phn tch vo nn i sau A l A + B v A+B+C. Chc mt phncht tinh khit A i trc



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A

c2- Phn tch thy- Trong sc k ny, chng ta cng np lng nhhn hp cht phn tch A, B, C vo ct sau

cho cht D l cht y lin tc i qua ct. i lc hp thl A


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ion, hp ph, phn b, ry phn t. Ngc li sc k hp ph xt vmt tng tc pha c ththucloi sc k - rn hay lng- rn.

- Sc k ra gii c ng dng nhiu trong lnh vc phn tch do hiu qutch cao3, Cc lc lin kt trong hsc k

- Trong hsc k c ba thnh phn chyu tc quyt nh stn ti ca h, cht phn tch, phatnh, pha ng to nn sphn bcn thit, gip cho sdi chuyn cc cht phn tch dc theo chiudi ct vi tc khc nhau. Chng ta thng ni cht phn tch phn bgia hai pha, tuy nhin yla cn bng ng cht phn tch lun thay i pha lin kt (trmt strng hp c bit n chmtpha trong sut qu trnh phn tch) vn l ti sao cht phn tch c gitrong pha tnh? Hn na bathnh phn ny tng tc nhthno vi nhau, bng cc lc lin kt no m kt qucc cht phntch li phn bvo pha tnh mc khc nhau? Cu trl do bn cht cc ca cc thnh phn tronghsc k. Cht phn tch c thl ion, phn ttrung ho hay cht phn cc, i tng lin kt ca ncng c thl ion, phn t, cht phn cc. Nhvy tuy thuc vo ln ca in tch kich thc phnt, phn cc m chng tng tc vi nhau theo cc lc lin kt khc nhau.Ngi ta chia cc lc linkt thnh bn loi:a/ Lc lin kt ion

- Trn bmt pha tnh c cc trung tm hot ng l ion. l cc phn tc khnng phn lyto thnh cc ion, to nn trung tm hot ng ion chung tham gia lin kt vi cc ion cht phn tchtrong dung dch theo lc tng tc tnh in gi l lin kt ion. gicc anion cht phn tch trongdung dch pha tnh cn c cc trung tm cation trn bmt, v ngc li gicc cation cht phntch trong dung dch pha tnh cn c cc ctrung tm anion cng tng t, pha ng cng c cc trungtm hot ng l cc ion, chng tham gia tng tc vi cht phn tch v pha tnh. Chng c khnngphn li trong dung dch to thnh cc cation v anion. Th d khi ra gii cc ion kim loi trn ctcationit, ta c thdng pha ng l dung dch HCl long. Cc phng php sc k thng gp c stham gia ca cc lin kt ion gi l sc k ion, sc k cp ion.b/ Lc phn cc

- Trong phn tcht phn tch, cht ra gii trong pha ng cng nhcc phn ttrn bmtpha tnh c cc trung tm phn cc, chng c th l cc lng cc in cnh, cng c th l cclng cc in do cm ng. Cc trung tm phn cc ca cht ny lin kt vi trung tm phn cc cacht khc bng lc lin kt phn cc. Sphn cc trong cc phn ti khi rt nh v schnh lchvphn cc cng rt nh. Tuy nhin, schnh lch ny l yu tquan trng c bn lin ktkhc nhau, l iu cn thit phn chia chng trong cc php tch sc k.

V d:cc Cresol (o-, m-,p- cresol) chkhc nhau vvtr nhm CH3- trong phn t. Chnh skhc nhau vvtr ny lm cho mt electron trong phn tcresol khc nhau to nn mt skhcbit nhvphn cc, t lc lin kt vi pha tnh khc nhau. L nguyn nhn chnh lch thi

gian lu trong qu trnh sc kc/ Lc Van- de- Van (lc phn tn)

- Lc ny c bn cht in, tuy nhin khng h c cc in trong mng li phn t, cngkhng lin quan ti phn tlng cc hay cnh. Tng tc phn tn in hnh l mch hidrocacbonn l tng tc phn t.

V d:n-heptan l cht lng chkhng phi l cht kh stng tc gia cc phn tn-heptanl lc phn tn ln gi cht ny trng thi lng. tch cc hidrocacbon ngi ta dnghidrocacbon khc lm pha tnh.d/ Lc tng tc c bit



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- Lc tng tc c bit l lc tng tc to thnh do cc lin kt hydro, lin kt cho nhn mc.Shnh thnh lin kt ginguyn thidro v cc nguyn tc m in cao nhO, N, F... gi llin kt hidro. Khi tham gia lin kt, cc electron cn gi l m my electron chuyn dch sangnguyn tc m in ln hn. Nhvy cc nguyn tc m in cao hn, lin kt hidro cng

bn cht.4, Stng tc gia ba thnh phn trong hsc k, ti u ho hsc k- Khi np cht phn tch vo hsc k, n c phn bgia hai pha, pha tnh v pha ng, tu

theo lc lin kt gitng pha vi cht phn tch m chng c thi gian pha no nhiu hn. Nhvythc cht l ba thnh phn trong hsc k tng tc vi nhau, pha tnh, pha ng, v cht phn tch. Taxt tng thnh phn v quan hca chng.

- Pha tnh phi lu gic cht phn tch, tuy nhin tch c cc cht, n khng c giqu cht cht phn tch c iu kin phn bvo pha ng v sau , mt thi im khc, n libhp thvo pha tnh. Cc cht phn tch c tnh cht cng ging nhau sphn bcng phi lp ilp li nhiu ln, y ta mun ni n sln phn bt cn bng hay sa l thuyt phi ln tch c hiu qu, do cc vn vt liu lm pha tnh, chiu di ct tch v cch np ct cng cnc quan tm. Ngy nay ta c thsdng nhng ct c sn trn thtrng nhng i khi, cng mtloi pha tnh, cc hng khc nhau c thto c cc sn phm vi tnh cht khc nhau.

- Vn tip theo l pha ng v cch vn hnh tc l tc pha ng, nhit , lng mu avo ct, ti sinh ct...Pha ng phi ho tan dc cht phn tch, tuy nhin thnh phn pha ng phiph hp sao cho cht phn tch khng bgiqu lu pha ng n c thlin kt trli vi phatnh.

- Stng tc gia pha ng v pha tnh cng l vn cn bn. Pha ng khng c lmnh hng ti pha tnh, khng lm thay i tnh cht ho l ca pha tnh. Pha ng khng c lin ktvi pha tnh mt cch qu bn vng to iu kin cho cc cht phn tch c thphn bvo pha tnhc. Ngoi ra tc pha ng, nhit htrong c nhit ca tng bphn ring, c bit l

trong sc k kh phi c quan tm khng chmt cch cht ch.- lm sng tvn trn ta ly mt v dtch cc ion kim loi M+bng phng php sc k

trao i ion. Pha tnh l cationit axit mnh, nhm trao i l R-SO3H: Pha ng l dung dch m ccht ra gii l H+. Stng tc ca ba i lng trn c miu tbng hnh sau:

Stng tc ca 3 i lng chyu trong hsc kPha tnh (RSO3) c khnng hp thcht phn tch theo phn ng sau:

R-SO-3 +M+ R-SO3M *

Mt khc cht ra gii trong pha ng cng tng tc vi pha tnh theo phn ngR-SO3

-+ H+ R-SO3H **- Ion kim loi M+cn lin kt vi pha tnh mt mc khng qu bn vng, phn ng hp th

y l phn ng thun nghch. Cn bng phn bl cn bng ng v hp cht R-SO3M c lin kt bnvng sao cho M+ddng i vo pha ng. n lt H+, khng c lin kt bn vng vi R-SO3

-, ni

cht phntch M+

Pha ng

H+

Pha tnh

R-SO3-



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mt cch khc l nng H+khng qu cao sao cho phn ng ** xy ra thun nghch. Mt khc tngtc gia M+v H+l tng tc phnh nhau, cnh ranh nhau. Chnh H+l yu tcnh tranh chophn ng ** xy ra. Nhvy vai tr ca nng cht ra gii,(H+) y rt quan trng n c gi trph hp sao cho hiu qu tch tt nht. Phng php a thm cht to phc vo pha ng cng

thng c p dng trong sc k trao i ion.III- Mt si lng dng trong sc k1, Hsphn bKDv cch xc nh

Cu tA phn bgia pha ng v tnh khi cn bng c thit lpAsAm (1)

hsphn bc nh ngha l tsca nng cht phn tch gia hai pha[ ]

[ ]m

K

s

AD

A= (2)

Trong : [Am] l nng cht phn tch trong pha ng[As] l nng cht phn tch trong pha tnh

Cn bng phn btrong pha kh gi l cn bng ng l cn bng gia lng - lng, kh-lng,rn-lng. Gischt phn tch c phn bphn no ca ct, a thn. Nhng do pha ng dichuyn, cht phn tch li i xung a th(n+1) v y li thit lp cn bng mi ca ca thn vn+1.

cn bng thit lp nhanh mt yu cu rt cn thit l lp pha tnh phi mng, hskhuchtn ca cht phn tch trong pha tnh ln hn hskhuch tn trong pha ng. Hsphn bKDcthc xc nh theo phng php tnh bng cch o nng cht phn tch trong pha ng v nngcht phn tch trong pha tnh sau khi t cn bng. Mt cch gn ng KDc xc nh theo

cng thc sau: ( )1

1

.

.DM M V

KM m

= (3)

Trong : M l lng cht ban u tnh bng mgM1l lng cht phn tch cn li sau khi tip xc mgV l thtch pha ng mlM l lng cht hp th, gam

2, Slin hgia tc di chuyn ca cht phn tch v KDCht phn tch A mun di chuyn c phi pha ng. Gi fAl phn thi gian A pha ng:

[ ]

[ ] [ ] [ ]mm

Amm s s

A .Vf

A .V A . V=

+ (4)

chia ctv mu cho [A]m. Vm ta c: AS

Dm

1f

V1 KV

=

+

(5)

Hay AA

1f

1 f=

+ (6)

Trong kA l hsdung tch.Tc tuyn tnh ca cu tA trong pha ng l:uA = u.fA = u / (1+fA) (7)

U l tc tuyn tnh ca pha ng (cm/s). Tbiu thc (6) v (7) ta c nhn xt: Khi DKhoc fAcng ln ; thi gian cht phn tch trong pha ng cng t, ni cch khc l cht phn tch di chuyncng chm, ngc li khi fAcng nh, cht phn tch di chuyn cng nhanh.



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3, Thi gian lu tR, thi gian lu hiu chnh tR

- Thi gian lu tRl thi gian lc bt u bm mu vo u ct ti khi pic t gi trcc i.A

RA

L L(1 k )t

u u

+= = (8)

L/u l thi gian m cu tkhng lu gitrn ct cn gi l thi gian cht

A

sR m D m A

m

Vt t (1 K . ) t (1 k )

V= + = + (9)

thi gian lu hiu chnh tRl thi gian lu khng tnh thi gian cht

A

" '' ' R R

R R m mm m

t Vt t t t .k k

t V= = = = (10)

4, Thtch lu Vm, thtch lu hiu chnhThtch lu VRl thtch ca dung dch ra gii tkhi bt u bm mu vo ct cho n khipic t cc i. Gi F l tc chy ca pha ng ml/pht,th tch lu VR c tnh theo cngthc:VRA= tRAF; Vm= tmF

VRA= Vm(1 + k) (11)Thtch lu hiu chnh VR l thtch lu loi i thtch trng ca ct

VR = VR Vm= VmkA = KDAVSThtch lu ring Vgl thtch ring cho cu t, l thtch dung dch ra gii ra cht phn

tch trong mt n vtrng lng hay thtch ca pha tnh

gDA

S

RA VK

V

V== (12)

5, Hstch (cn gi l hslu gitng i)- Hstch l i lng nh gi khnng tch hai cht bng phng php sc k. N ph

thuc vo hsphn bca chng v tsca hsphn bca hai cht: mt cht phn tch A vmt cht khc B hoc mt cht chun.iu kin hai cht tch khi nhau l 1

'DB B

ADA

k

k

K

K== 1 (13)

Ni mt cch khc hsphn bca hai cht A v B gia pha tnh v pha ng phi khc nhau.Mt khc tsthtch lu ca hai cht, tRA/ tRBcng chnh l tsca hsphn b.

Vy c thtm tt l:'

'

'

'

'DB RB

RA

RB

RA

B

ADA

V

V

t

t

k

k

K

K==== (14)

6, Sc .- Sc l sbiu din sphthuc din tch (S) hoc chiu cao (h) tn hiu o c c thl

hp thquang,cng c thl dn in hoc l tn sxung in ...lin quan cht chti nng cht phn tch c trong mu v thi gian. Cc tn hiu ny c gi l pic sc k.tnh ton hmlng cht phn tch, tnh din tch pic sc k l chnh xc nht.Ngy nay hu ht cc my hin i uc trang bcc thit btnh din tch ca pic sc k mt cch tng



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Sc hai cu tA&B

7,a l thuyta/ Khi nim a l thuyt:

a l thuyt l phn no ca ct m cn bng c thit lp. Theo quan nim caMartin v Synge, cn bng c thit lp nhanh chng, tc thi. Tuy nhin iu ny gp kh khn khigii thch hin tng gin rng vng mu, hin tng pic sc k khng cn i. Amundson v Lapidusv sau l Van Deemter cho rng a c cn bng khi t cn bng chuyn khi lng cht tan tpha ng vo pha tnh v ngc li v tc gi a ra thuyt tc .

Nhvy c thni rng phn nhca ct gi l a l thuyt khi t c cn bng phn bcht phn tch.

Gi n l sa l thuyt, l lch chun; ~ n . i vi ct sc k n cng ln pic cng

hp, thi gian lu tlvi sa l thuyt n, tR~ n, nn ta c thvt: nnt

R = hay

2

=

R

tn mt

khc w = 4 hay4

W=

sa l thuyt c thvit li l:22

R R

1/ 2

t tn 16 5,54

W W

= =

b/a l thuyt c tnh thi gian khng lu gi, nef

( )( )

2

22R m ' 2 '

ef R m2 2 2

t t 16 16n 16 t t k

w W W

= = = (14)

RBRB Vt .

'' , RBRB Vt

RARA Vt ,

''RA , RAVt

hS,

AW BW

Vt,mt

0t

Xc nh sa l

thuyt thc nghim



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( ) ( )

2 2 2R

ef 2 22

t k kn 16 n.

w 1 k 1 k= =

+ + (15)

V t(8) ta c tm= tR/(1+k). Chiu cao a l thuyt hiu lc c tnh:

(16)

t(15) v (16) ta c:( )

( )2

2'2

e f 2 'R m

1 kL wH H

1 6 kt t

+= =

(17)

8, phn gii v cch lm tng phn gii:a)phn gii

phn gii ni ln mc tch cu tkhi nhau trong mt php tch sc k. Hai cu tAv B c tch khi nhau cng trit , phn gii cng cao. phn gii c nh gi qua cc ilng c trng l: thi gian lu, tRA, tRBv rng pic WA, WB.

phn gii R c tnh theo cng thc:( )RB RA

A B

2 t tR

W W

=

+ (18)

Trong : tRB tRA= tRl schnh lch thi gian lu(cng c thdng thtch lu VRA- VRB)ca haicu tA v B. i lng ny c so snh vi tng bn chiu rng pic, o bng giy hoc mililt, niln khnng tch ca ct.Khi tng chiu di ct, s a l thuyt tng: tR ~ n, chiu rng pic t l vi n V vy

R~n

n hay R~ L

b/ Cch lm tng phn gii- Cch thnht: Da trn s thay i cu trc ct. Trong phng php ny c cc bin php:

Tng chiu di ct, sdng cht nhi c kch thc ht nhhn, ng u hn, thay i pha tnh vcui cng l gim ng kinh ct

- Cch thhai: Da trn cch vn hnh ct: l ti u ho tc pha ng, gim lng mu,gim nhit ct (GC) v cui cng l thay i thnh phn pha ng (LC)9, Thuyt tc , phng trnh Van Deemter

- Thuyt c cc tc giLapidus v Amundsion a ra nm 1952, sau ny c Van Deemterpht trin.

- Theo thuyt ny cc yu t: ng knh ht nhi, kthut np ct v cc yu ttc ca pha

ng, hskhuch tn ca cht phn tch trong pha ng v pha tnh nh hng rt nhiu ti sginrng vng cht phn tch hay rng ca pic trong sc . i lng c trng cho gin rng cavng cht phn tch l chiu cao a l thuyt H, c hnh thnh do ba thnh phn H1,H2, H3.

H = H1+H2+H3 (19)H1 l i lng khuch tn xoy, c trng cho sng u ca ct nhi, ng knh ca ht

nhi, khnng np ctH1= 2dp (20)

Trong l hsnp ct, nu np ct tt th = 1,5; dpl knh ht nhiH2l i lng khuch tn theo chiu dc. N c hnh thnh do skhuch tn ca cht phn

tch v hai u ca ct, phthuc vo tc ca pha ng, hskhuch tn ca cht pht phn tch

trong pha ng, ng i ca cht phn tch, c biu din bng phng trnh:

f

fnLH =



39/68



H2 = B/u trong B= 2DmL i lng c trng cho hskhuch tn ca cht phn tch trong pha ng v hsng i can. Trong iu kin np ct tt, ng i ca cht phn tch khng qu khc khuu, = 1; Dml hskhuch tn ca cht phn tch trong pha ng, nhvy H2c thvit li l:

H2= 2Dm/u (21)H3l i lng c trng cho qu trnh chuyn khi lng l yu tphthuc vo tc hp thv gii hp. Qu trnh ny phthuc vo cpha ng v pha tnh, v vy H3c thvit:

H3= (CS- Cm)u (22)Trong Csl hsdc trng cho qu trnh chuyn khi lng ca cht phn tch trong pha tnh, phthuc vo pha tnh, n c gi trnhkhi tc dng F1ml/pht, Cs 0

Cs= K.df2/Ds (23)

Trong : K- hsDs- hskhuch tn cht phn tch trong pha tnhdf

2- chiu dy pha tnh

ng cong Van DeemterCml hng schuyn khi ca cht phn tch trong pha ng, phthuc vo pha ng, c xc nh

theo biu thc:Cm= dp

2/Dm (24)l hsthc nghim c gi trt0,5- 1Dml hskhuch tn ca cht phn tch trong pha ng.

Tng hp li H c biu thc tng qut l:H = 2dp+ 2Dm/u + (Kdf

2/Ds+ df2/Dm)/u (25)

Phng trnh trn c vit tt l:H = A+B/u +Cu (26)

Trong thc tc thtnh gn ng H= 3-4dpxt cc tiu chiu cao ca a l thuyt ly o hm ca phng trnh Van Deemter ta c:

H= -B/u2+C

ti cc tiu H=0 => ut=C

B

H

minH

u

B

Cu

scmu /,

A

tuu



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MT STHUC THHU CDNG TRONG TCH CHIT

V SC KALIZARIN COMPLEXONE

Cng thc. Cng thc phn t: C19H15NO8.2H2O Khi lng mol: 421.36 v.C. Vit gn: H4L Cng thc cu to:

Danh php:Cc danh php thng dng:- 3 - [ Di ( carboxymethyl) aminomethyl ] 1,2 dihydroxyanthraquinone.- 1,2 - dihydroxyanthraquinone - 3 - ylmethylamine - N.- N - diacetic acid hoc Alizarin Complexone hoc ALC.

Cc tnh cht ca chth.Chthdng tdo.

Lun tn ti dng acid tdo ngm nc; bt tinh thmu vng nu, nhit nng chy: 1900C; hu nhkhng tan trong nc, te, alcohol v cc dung mi hu ckhng phn cc, nhng tan ddng trong dung dch kim. Mu ca dung dch chththay i theo pH v cc nc phn ly ca chthc trnh by theo ssau ( = 0.1):

H4L H3L-

H2L2-

HL3-

L4-pKa1= 2 . 4 0 pKa3= 1 0 . 0 7 pKa4= 1 1 . 9 8pKa2= 5 . 5 4

- COOH 2 OH N+H 1 OH

Yellow Red Red Blue Quang phhp thu ca chthtrong dung dch cc gi trpH khc nhau c minh hohnh 1.

Phn ng to phc v cc tnh cht ca phc.Cc ion kim loi to phc mu vi Alizarin Complexone c thc chia thnh 2 nhm. Nhm

thnht l cc ion kim loi to phc (MHL) pH = 4.3 - 4.6, pH ny chthtdo c mu vng.Nhm thhai l cc ion kim loi to phc -tm (ML) ti pH = 10, pH ny chthtdo c mu .

+ Nhm 1: Ba, Ca, Cd, Mg, Mn(II), Ni, Sr.

400 500 600 700Bc sng

1.00.8

0.40.6

0.2

1.21.4

12 3

4

5

hpt

h

Hnh 1. Quang phhp thca ALC ccpH khc nhau.(1) pH 4.6; (2) pH 7.0;(3) pH 10.0;(4) pH 11.5; (5) pH 13.0;Hm lng 9.96 ppm trong nc.

CH2COOH

CH2COOH2 H2O

O

O OHOH

CH2N



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+ Nhm 2: Al, Cd, Ce(III), Co(II), Cu(II), Fe(III), Ca, Hg(II), In, La, Mn(II), Ni, Pb, Th,Ti(III)(IV), Zn, Zr, v t him.

Hng sto thnh ca phn ng:M2++ HL3-MHL- llgK = 12.19 (Zn), 12.23 (Ni), 12.25 (Co), 14.75 (Cu).

Cn phn ng:HML-+ M2+M2L + H+

l lgK = 0.8 (Pb) v 3.5 (Cu) ( = 0.1, 200).

Cu to ca MHL nhsau:

O OH2OH2

O

CH2

C

O

M

CH2

O

C

H2C

NO

O OH

Phc ca cc ion t him pH ~ 4 chuyn thnh mu xanh khi c mt ion F-do c sto

phc MLF. Trong cc nguyn tt him thphc ca La (III) v Ce (III) c si mu nhy nht, vphn ng ny c sdng nhmt phng php quang phc bit c nhy cao xc nh ionF-.

Skt hp ca F-lm suy yu lin kt O - H, do n c thphn ly pH = 4 pH ny chthtdo khng phn ly c.

O

O O

O M

CH2 N

F-H

OH2

Quang ph hp th ca phc LaHL vLaLF c minh hohnh 2.

700400 500 600Bc song(nm)

0.2

0.4

0.6

0.8

1.0

1.4

1.2

ohapthu

400 450 550 650

12

3

HNH 2. Quang phohap thu cua phc La-ALC va phc La-ALC-F.(1) LaHL; (2) LaLF;(3) s khac nhau gia

LaHL va LaLF; nong o0.002M; F-, 20g.



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Phc mu xanh c thc chit vi dung mi hu cnu nhnc ion t him c thay thbng ligan hydrophobic nhalkinamine hay arylamine. Qu trnh chit da trn tnh cht ca dungmi chit v cc amin, v iso butanol hoc iso amylalcohol cha 5% N, N diethylaniline cho ktqutt nht. Hnh 3 minh hoquang phhp thu ca dng chit.

Cc hng scn bng ca hthng La -ALC v La -ALC-F c tm tt trong bng 1.Bng 1: Cc Hng sbn ca hthng LA-ALC v LA-ALC-F 250C

Cn bng Hng scn bngA.Hthng La -ALC2M + 2H2LM2L2+ 4H

+2M + 2H2LM2HL2+ 3H

+lgK202= 0.28lgK212= 5.58

B. Hthng La -ALC-F2M + 2H2L + F

-M2HL2F + 3H

+

2M + 2H2L + F-M2H2L2F + 2H+lgK2121= 9.70

lgK2221= 14.17Cch tinh chv tinhkhit ca thuc th.

- Hu ht cc mu thuc thbn trn th trng c thsdng cho cc vic phn tch thngthng khng cn tinh khit. Nhng i vi nhng php phn tch cn tinh khit thcn phitinh chthuc thtrc khi dng. Qu trnh thc hin nhsau:

- Cn chnh xc 1 (g) bt mu cho vo 50ml dung dch NaOH 0.1M, lc dung dch, ri emchit Alizarin 5 ln bng Methylenedichloride. Lm lng chthtdo bng cch thm tng git acidHCl v khuy u trong mt bn lnh. Lc phn lng trn mt phu lc thutinh, ra sch bng nclnh, v lm kh bng thit bc chn khng.

- tinh khit ca acid tdo c thkim tra bng php o kim hoc chun trc quang vi dung

dch chun Al pH = 4.Cc ng dng phn tch.Sdng phc vi Ce hoc La lm thuc thtrong php o quang cho Fluoride.

- Khong pH tt nht cho phn ng to mu l t4.5 - 4.7, v bn cht ca cc dung dch mcng nh hng ti nhy ca phn ng. m Succinate c sdng nhiu nht, hnhp dungdch thuc thlc ny sc n nh trong khong 9 thng. Cn m Acetate thc sdng chophng php chit trc quang. Sc mt ca dung mi hu ccng lm tng nhy, v Acetone(20% - 25%) cho kt qutt nht. Mu c n nh trong 1 gi. nhy cng c thc tng lnnhdung mi chit. Vic thm Natri dodecysulfate cng lm tng nhy phn ng mu ny.

- Cc cation nhAl, Be, Th, Zr, gy cn tri vi phn ng mu, chng cnh tranh vi thucth trong vic phn ng to phc vi F -. Cc cation nhAl, Cd, Co(II), Cr(III), Cu(II), Hg(I)(II),

500 550 600 650 700

0.4

0.6

0.2

0.8

Bc sng

hp

th

H?NH 3. Quang phhp thcaphc La -ALC-F trong dungdchiso-amylalcohol cha 5% N,N-diethylaniline; F,0.5ppm.



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Fe(II)(III), Mn(II), Ni, Pb, V(IV), Zn, cng gy cn tr, chng to phc vi Alizarin Complexone bnhn so vi cc ion t him. Cc Anion nhBO3-v PO4

3-cng gy nh hng, chng to phc bnvi cc ion t him.Qu trnh trc quang i vi Fluoride trong dung dch nc.

- Dung dch thuc th:+ Chuyn mt vi ml dung dch nc cha 47.9 mg Alizarine Complexone, 0.1 ml dung dchAmmonia c v 1 ml Ammonium Acetate vo bnh nh mc 200 ml cha sn dung dch c pha t8.2 g Natri Acetate v 6ml Acid Acetic c trong mt lng nh nc. Thm 100 ml Acetone vkhuy u. Ri sau thm tip mt dung dch c pha t40.8 mg La2O3trong 2.5 ml HCl 2N. Cuicng, nh mc ti vch bng nc ct. Dung dch ny c n nh trong 2 tun.

- Qu trnh xc nh:+ Cho mt cht kim yu hoc mu dung dch trung tnh c cha 3 g - 30 g F-vo bnh nh

mc 25 ml. Thm 8.00 ml dung dch hnhp thuc thri nh mc ti vch. Sau 30 pht em o phhp thu bc sng 620 nm. Lm mu trng khng c mu cha F-.

- Qu trnh chit trc quang i vi Fluoride.+ Cho 20 -30 ml dung dch mu cha 0.5 - 10 g F -vo trong phu chit 100 ml. ln lt thm 3ml

dung dch Alizarin Complexone 0.001M, 3ml dung dch m Acetate (pH = 4.4), 8ml Acetone, v 3ml dungdch Lanthanium Chloride 0.01M, ri pha loa?ng hnhp ti 50ml. chit phc mu xanh bng cch lc dungdch nc vi 10ml Iso - amyl alcohol cha 5% N,N-diethylaniline trong 3 pht trn my lc. Sau khi c sphn chia pha, em o phhp thu ca pha hu cbc sng 570nm. Lm mu trng l dung dch khngcha mu. nh lut Beer c p dng ng trong khong nng ca F-l 0 - 10 ppm.Cc ng dng khc.

- Alizarin Complexone c sdng trong phng php trc quang xc nh cc ion kimloi nh: Al (pH = 4.1 - 4.3, = 455nm), Cu(II) (pH = 3.5), Mn(II) (trong kim, = 570nm), Co(II),Ni(II) (pH = 4.5, = 500nm), V(IV) (pH = 10.3 - 10.8, acid ascorbic, CPC).

- N cng c sdng nhl mt chthkim loi trong php chun to phc ca Co (II), Cu(II)

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