Mass selective detector coupled to gas chromatography (GC-MSD) and to thermogravimetry (TG-MSD)

Mass selective detector coupled to gas chromatography (GC-MSD)

and to thermogravimetry (TG-MSD)

Dr. Mihai Brebu

1. Gas chromatography (GC)

2. Thermogravimetry (TG)

3. Mass selective detector (MSD)

4. Gas chromatography - Mass selective detector (GC-MSD)

5. Thermogravimetry - Mass selective detector (TG-MSD)

Institutul ‘Petru Poni’ Iasi, aprilie 2009

1. Gas chromatography (GC) Institutul ‘Petru Poni’ Iasi, aprilie 2009

Gas chromatography: analysis technique for qualit./quantit. determination of compounds in mixtures

Compounds separation by selective adsorption/desorption affected by temperature, gas flow (for a given column)

Detection of compounds based on specific properties

Recording/analysis/display of signal

Vaporisation, mixing with carrier gas, injection in the column

Column

Detector

Recorder

Inlet

retention time (rt) depends on: characteristics of the column (length, diameter, filling) polarity of compounds (rt izooctan < octena < octan) molecular weight of compounds (rt heptan < octan < nonan) temperature program (rt decreases at high temperatures) carrier gas flow (rt decreases at high flows)

0.8e+7

0.6e+7

0.4e+7

0.2e+7

0 2 4 6 8 10 12 14 16 18 20 22 24 0

retentiontime (min)

response

a: 100(1),10>220 oC; 1ml/minb: 150(1),10>220 oC; 5ml/minc: 150(1),10>220 oC; 10ml/min

Sa

Va

Sb

Vb

Sc Vc

effect of temperature and flow rate

effect of flow rate

Vanilin (V) in EtOH as solvent (S)

GC-FID

1.0e+7

2 3 4 5 6 7 retention time(min)

abundance

31(8) oC; 1ml/min

26(8) oC; 1ml/min

26(4),10>70 oC; 0.6ml/min1.0e+7

1.5e+7

0.5e+7

1.0e+7

1.5e+7

0.5e+7

1.0e+7

1.5e+7

0.5e+7

Ambient gas sample

qualitative analysis: - from retention times - from MSDquantitative analysis: - from peak area

1. Gas chromatography (GC) Institutul ‘Petru Poni’ Iasi, aprilie 2009

good balance between short analysis time and good separation of compounds

2. Thermogravimetry (TG) Institutul ‘Petru Poni’ Iasi, aprilie 2009

Thermogravimetry: analysis technique for thermal processes involving mass loss (thermal degradation)

thermal behaviour - described by: temperature for onset of the degradation step temperature for maximum rate of degradation temperature for end of the degradation step final mass loss of degradation step

thermal behaviour - affected by: temperature program (heating rate) atmosphere (air, inert gas) sample mass

Polyurethane


0

20

40

60

80

100

250 300 350 400 450 500 550 600Temperature , oC

Sam

ple

wei

gh

t , w

t%

DT

G -

der

ivat

ive

wei

gh

t lo

ss

PEPPPSHIPS-BrABSABS-BrPVCPET

HDPEPPABS

PS

PET

ABS-Br

HIPS-Br

PVC

HIPS-Br: DTG

aplications: thermal stability - lifetime predictions


aplications: kinetic studies: activation energy (Ea), reaction order (n), pre-exponential factor (A)

100 200 300 400 500 600Temperature/°C

10

30

50

70

90

Mass/%

10 oC/min

100 200 300 400 500 600Temperature/°C

10

30

50

70

90

Mass/%

20 oC/min10 oC/min 5 oC/min

the kinetic model should correspond to a plausible degradation mechanism !!!

Polyurethane

3. Mass selective detector (MSD) Institutul ‘Petru Poni’ Iasi, aprilie 2009

Mass selective detector: qualitative identification of compounds based on fragmentation pattern (EI)MS spectra for aliphatics


MS spectra for aromatics


MS spectra for brominated compounds

79+15 81+15

79*2+14 81*2+14

79*2+13 81*2+13

79+81+1479+14

81+14

79+81+13

79+12 81+12

81+13

M=95

M=174

M=253

79*3+13 81*3+13

79*2+81+13 79+81*2+13

Br: 79.904; g mol-1

79Br (50.69%); 81Br (49.31%)

Time

Abundance

1.2e+7

1.0e+7

0.8e+7

0.6e+7

0.4e+7

0.2e+7

5 10 15 20 25 30 35 40 45 50 55 60 65 0

20000

40000

60000

80000

100000 ion 81

4. Gas chromatography - mass selective detector (GC-MSD) Institutul ‘Petru Poni’ Iasi, aprilie 2009

HBr

PhCHBrCH3

???

???

HIPS-Br degradation oilTIC


I

II

HIPS-Br degradation oil - detail TIC

HIPS-Br degradation oil - scan at 34.59 min


I

II


ambient gas sample – TIC(26(4),10>100; 0.6ml/min)

2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 3.600

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

21000

22000

23000

24000

Time-->

Abundance

Ion 27.00 (26.70 to 27.70): GAZE05.D\data.ms

ion 27 – HCN at rt 2.05

2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00

2.02 2.02 2.03 2.04 2.04 2.04 2.05 2.06 2.06 2.06 2.07 2.08 2.08

500000

1000000

1500000

2000000

2500000

3000000

3500000

4000000

4500000

5000000

5500000

6000000

6500000

7000000

7500000

8000000

8500000

9000000

9500000

1e+07

1.05e+07

1.1e+07

1.15e+07

1.2e+07

Time-->

Abundance

TIC: GAZE05.D\data.ms

detailed TIC at rt 2.03 – 2.06


ambient gas sample – TIC

2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.500

500000

1000000

1500000

2000000

2500000

3000000

3500000

4000000

4500000

5000000

5500000

6000000

Time-->

Abundance


2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 4.20 4.40 4.60 4.800

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

Time-->

Abundance


ion 41 – acetonitrile: 2.78

ion 54– 2-propenenitrile: 2.97– propanenitrile: 3.60

5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.000

200000

400000

600000

800000

1000000

1200000

1400000

1600000

1800000

2000000

2200000

2400000

Time-->

Abundance

Ion 86.00 (85.70 to 86.70): GAZE05.D\data.msIon 101.00 (100.70 to 101.70): GAZE05.D\data.ms

ion 86; ion 101– triethylamine: 6.07

2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00

5. Thermogravimetry - mass selective detector (TG-MSD) Institutul ‘Petru Poni’ Iasi, aprilie 2009

0.0E+00

2.0E-10

4.0E-10

6.0E-10

8.0E-10

1.0E-09

1.2E-09

1.4E-09

1.6E-09

1.8E-09

2.0E-09

50 150 250 350 450 550 650 750 850Temperature , oC

MS

inte

nsity

, a.

u.

0

20

40

60

80

100

TG

, %

2 12 15 16 17 18 26

28 29 30 43 44 Tic Tg

Pc: 5.6 mg

0.0E+00

1.0E-12

2.0E-12

3.0E-12

4.0E-12

5.0E-12

6.0E-12

7.0E-12

8.0E-12

9.0E-12

1.0E-11

50 150 250 350 450 550 650 750 850Temperature , oC

MS

inte

nsity

, a.

u.

0

20

40

60

80

100

TG

, %

2 12 15 16 17 18 26

28 29 30 43 44 Tic Tg

Pc: 5.6 mg



0.0E+00

2.0E- 10

4.0E- 10

6.0E- 10

8.0E- 10

1.0E- 09

1.2E- 09

1.4E- 09

1.6E- 09

1.8E- 09

2.0E- 09

50 150 250 350 450 550 650 750 850Temperature , oC

Ms

inte

nsi

ty , a

.u.

0

20

40

60

80

100

Tg

, %

2 12 15 16 17 18

28 29 43 44 Tic Tg

Pc/CaNi: 37mg - 4.6 mg Pc


0.0E+00

5.0E- 12

1.0E- 11

1.5E- 11

2.0E- 11

2.5E- 11

3.0E- 11

50 150 250 350 450 550 650 750 850Temperature , oC

Ms

inte

nsi

ty , a

.u.

0

20

40

60

80

100

Tg

, %

2 12 15 16 17 18

28 29 43 44 Tic Tg

Pc/CaNi: 37mg - 4.6 mg Pc


PEG


PU


-FeOOH -Fe2O3 • H2O Fe3O4

m/z 17 vs m/z 18 - ct.

changes in composition and structure of -FeOOH during catalytic degradation of ABS


reaction of 4-phenylbutironitrile over -FeOOH catalysts and its derivatives

NH3:14,15,16, 17/18

reduction of catalyst by organic compounds

alkyls: 27,28,29,14,15

toluene, ethylbenzene: 91

aliphatic nitriles: 41,14,15,16,28,29

Institutul ‘Petru Poni’ Iasi, aprilie 2009

Acknowledgements:

- Dr. Dan Rosu - Dr. Vasile Cornelia

- Dr. Nita Tudorache - Prof. Yusaku Sakata

Conclusions:

- MSD is a powerful detector for qualitative identification of compounds leaving a GC column or a TG furnace

- identification is facile in GC-MSD if compounds are well separated by GC and their structure is included in databases

- careful interpretation of mass spectra is need if compounds are not well separated by GC and their structure is not included in databases

- careful analysis of various mass signals is need for TG-MSD data since compounds are not separated and the mass signals might represent a sum of contributions from fragmentation of different compounds

Mass selective detector coupled to gas chromatography (GC-MSD) and to thermogravimetry (TG-MSD)

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