X-ray fluorescence analysis X ray fluorescence analysis

X-ray fluorescence analysisX ray fluorescence analysis

Chiba University Department of ChemistryChiba University, Department of ChemistryChiya NUMAKO, Misato KAZAMA

Tokyo University of Science，Department of Applied Chemistry

Izumi NAKAI

・・Introduction to Introduction to XRF XRF

・・Characteristics of SR and the advantagesCharacteristics of SR and the advantages inin・・Characteristics of SR and the advantages Characteristics of SR and the advantages in in XX--ray ray fluorescence analysis with application fluorescence analysis with application examplesexamples

(1) Highly (1) Highly Brilliant XBrilliant X--ray Sourceray Source( ) g y( ) g y yy(2) Parallel (2) Parallel beam with small divergence beam with small divergence : : --XRF XRF (3) Energy (3) Energy tunability tunability （（High EnergyHigh Energy））

XAFS HEXAFS HE XRFXRF-- ––XAFS, HEXAFS, HE--XRFXRF・・ConclusionConclusion

Recoil electronDiffraction

Principle of X-ray fluorescence spectroscopy (XRF)

Elastic (Thomson)Inelastic (Compton)Scattering

Transmitted X-rays (Absorption)IncidentX-rays

Diffraction

Fluorescence X-rays

Photo electron,Heat ray

IonAuger electronHeat ray

(XPS)

Interaction of X-ray with matterｔ (XPS)

(XRF)

Photoelectron

FluorescenceX-rays

Ph l

Io I

(AES)

( )Auger

electronAbsorption

Photoelectroneffect

X-ray Absorption

I = Io・e -t

(XRD)Thomsonscattering(XAFS)

p

Scattering*Crystal StructureLong-range ordering

I Io e

t = ln (Io / It)

4X-ray AnalysesComptonscattering

Scattering Long range ordering

光電子

蛍光 X 線(E)②


蛍光 X 線(E)(K線)

N

②photoelectron emission ③Fluorescence X-ray(K)

K

ML

K

X ray(K)

LM EbK K

K

K

L

原子核 core

入射 X 線(E) EbK < E

空孔

電子 electron

vacancy①X-ray irradiationith E

Bohr model and emission of X-ray fluorescencewith energy E

X-ray energy E ＞ Binding energy Eb


Upper stateEIncident X-rays FluorescenceX-rays

E

ElectronSampleHole

EE0

E = E - E0 Energy level of electron in an atom

Sample

E i l h diff b h l iE is equal to the energy difference between the two electronic state

ex) Flame reaction The color (energy) is unique to element

1000Principle of X-ray fluorescence spectroscopy (XRF)

c)PbK

Yb

ErTm

Nb K

Y K

Zr K

Th L

Pb L Pb L

Bi L

Th L

U L

Sr K

/100

0se

BiHf K

Re K Lu K

Lu

Ta

HfGd

D

Tb

U L, Mo K

Nb K

Sr K

500

Coun

ts/

Ca

ReK

W K

Ta KW

Ta

Ho

Dy

Sm

E

CePr

B

Cd

SnIn

Ag

ensi

ty (C K

LaNd EuBa

CsSb

Te

Inte

00 20 40 60 80

X-ray energy (keV)An example of XRF spectrum of NIST SRM612 glassEDS

Measuring energy and intensity of XRF signal


IntensityK

Measuring energy and intensity of XRF signal

Intensity∝ number of X-ray photons

t ti

ount

s BA

Quantitative analysis

→ concentration

Inte

nsity

/ c KK

K Quantitative analysis

Energy / keV

K

Energy ∆Ｅ

→ characteristic to each element→ characteristic to each element

Qualitative analysis

Chemical Composition Analyses

How to measure E and I of the fluorescence X-rays.

Ｘ線管

半導体検出器

試料

Ｘ線管

21

試料検出器

分光結晶

ソーラスリット

2212


面間隔

Ｘ線管Ｘ線管

半導体検出器

試料

Ｘ線管

試料

Ｘ線管

21

試料検出器

分光結晶


2212


面間隔Analyzing crystald-spacing

(a) Wavelength dispersive spectroscopy

WDS試料

(a) (b)

面間隔ｄ

分光結晶

試料試料

(a) (b)

面間隔ｄ

分光結晶

y g yd spacing

Energy of fluorescent X-ray can be

Bragg condition nλ=2dsinθEnergy of fluorescent X ray can be selected by controlling Bragg angle.

High EfficiencyMulti-elemental detection(b) Energy dispersive spectroscopy

EDS The detector should detect

Multi elemental detection

EDS both Energy and Intensity of fluorescent X-ray

→ SSD, SDD

©http://www.postech.ac.kr/dept/mse/axal/index.html

Y K

Zr K

h

Procedure of X-ray fluorescence Analysis (XRF)

1. Check the chemical composition for samples・・・Qualitative Analysis

U L, Mo K

Nb K

Th L

Pb LPb L

Bi L

Th L

U L

Sr K

2. Select the best condition for XRF analysesCombination of X-ray source, Detector,measurement time etc

U , o

Nb K

measurement time, etc.

3. Make calibration curve from standardsEnergy / eV

4. Calculate elemental concentration for the sample from the peak intensity

Q i i A l i・・・ Quantitative Analysis

Calibration Curve for Cd Concentration (ppm)

R2=0.9996, LLD=3.5 (ppm)

Quantitative analysis of HE‐SR‐XRF: correlation betweenpeak intensities and elements’ concentration

HE-SR-XRF spectrum of various reference rock powders, JLK-1, JR-2, JB-2 and JG-3

Concentration v.s.v.s.

net intensity

●Energy region between 30 ~ 60 keV: Lowest background, suitable for quantitative analysis for the background can be subtracted accuratelyfor the background can be subtracted accurately.

●Good correlation between the intensity and concentration of the elements

Quantitative analysis by HE-SR-XRF: calibration curve method

Calibration curves: 8 rock reference samples Comparison of HE-SR-XRF results with certified reference value of JR-2

● calibration curves :Good linearity with high coefficient of determination (R2)

● Fair agreement with the certified● Fair agreement with the certified value of JR-2

Application fields for XRF analysesSamples:Detector

・Solid, Liquid, and/or Gas・Crystal and/or AmorphousO i d/ I i

Detector

X-ray source

・Organic and/or Inorganic・Non-destructive ・Living sample, Archeological sample

・ Oil

Sample

Oil・ Industrial Waste・ Water・ FoodFood・ Soil, Rock, Mineral・ Fly Ash・ Glass, Ceramics

・ Elemental Analyses for matrices and impurities

・ IdentificationF i l

,・ Thin film・ Courting material・ Metal, Jewel

・ Forensic analyses・ Archeology etc.

・ Ink, dye, Cosmetics・ Polymer ・ Medical and Biological

① How to measure Fluorescence X-ray② How to select the X-ray source for Incident X-ray③ How to improve the Signal / Background ratioetc. ③ How to improve the Signal / Background ratio

Advanced properties of SR for XRF and XAFS analyses) i hl b illi d hi hl lli d ll l b1) Highly brilliant and highly collimated parallel beam

high intensity → signal enhancement, small sample

high collimation → microbeam analysis, total reflection analysis

2) Linear polari ation backg o nd ed ction2) Linear polarization → background reduction

3) White (Bending Magnet) or quasi monochromatic (Undulator) X-rays

monochromatic X-rays → background reduction

continuous energy scanning → XAFScontinuous energy scanning → XAFS

energy tunability → XRF：element selective excitation

Sample : Cu, Co, Mn, V, Sc, K 0.2ppm 50ml dried up on the holder

Sample : Cu, Co, Mn, V, Sc, K 0.2ppm 50ml dried up on the holder A B C

( ) 3 0 0

The Lower limit of Detection of XRF analysis

（）（） 40kV 1 A

Sample holder : Polyethylene 5mm filmＸ-ray tube : Mo Measurement time : 200sec

Sample holder : Polyethylene 5mm filmＸ-ray tube : Mo Measurement time : 200sec

P.I. (cps) 4.53 0.57 0.57 B.G (cps) 0.08 0.06 2.99

P/B 56.6 9.5 0.2A Monochromator method （Mo-K）Monochromator method （Mo-K） 40kV-1mA LLD/ppb 2.65 18.2 129A

Fluorescence X-rayIs

Filter method （75m Mo ）Filter method （75m Mo ） 40kV 1 AB

Incident X-raysScattering of X-rayIoIb

40kV-1mA

Ip

Direct methodDirect method 40kV-0 125mAC

Ibc: concentration of the elements40kV 0.125mA

LLD 3/ (I /I )1/2

Ib: background area intensityIp: peak area intensity

Improving Signal/Background ratio is most important points for XRF

LLD = 3/c ・ (Ib/Ip)1/2

Sensitivity of XRF analysis

is determined by Np and NB

XRFXRF spectrum

Np increase ＝ Signal increase

→ High brilliance source

NB decrease →

Monochromatic Excitation→ High brilliance source

High flux source

Monochromatic Excitation

WDX

Total reflection

Advanced properties of SR for XRF and XAFS analyses) i hl illi d i hl lli d ll l b1) Highly Brilliant and Highly collimated parallel beam







energy tunability (high energy) → XRF：element selective excitation

©A.Iida(PF)Beam size：mm ～ nm scale

Application Application of SRof SR--XRF to in vivo analysis XRF to in vivo analysis of biological sampleof biological sampleof biological sampleof biological sample

Study of hyperaccumulator plants ofStudy of hyperaccumulator plants of AsAs

300ｋｇ(fresh weight)

Study of hyperaccumulator plants of Study of hyperaccumulator plants of AsAs

300 ｇ(fresh weight)≒ 270ｇ As

A Hokura R Onuma Y Terada N KitajimaA. Hokura, R. Onuma, Y. Terada, N. Kitajima, T. Abe, H. Saito, S. Yoshida and I. NakaiJournal of Analytical Atomic Spectrometry, 21, 321-328 (2006)

Chi b k f (P i i L )©Fujita Co.

Chinese brake fern (Pteris vittata L.)As: ca. 22,000 μg /g dry weight

AsPhytoremediation

ashAsAs As

. ....

. ...

plant remediate

ash3: accumulation

As

AsGreen technology by plant

Merit：no damage, low costAs

AAs

Aspreservation of surface, etc.

Some specific kinds of plants are k t b h t l As isolationAsknown to be heavy metal hyperaccumulator

2: transportationElement conc / ppm plant

As

Contaminated soil1: absorption of heavy metal

Element conc./ ppm plantAs 22,630 Pteris vittata L.Cd 11,000 Athyrium yokoscensePb 34 500

*1

Contaminated soilheavy metalPb 34,500 Brassica juncea*1 L. Q. Ma, et al., Nature, (2001) , 409, 579.

Application of SR X-ray analyses pp y y

・Two dimensional multi-elementnondestructive analysis in cell level→→XRF imagingXRF imaging→→XRF imagingXRF imaging

Chemical state analysis in cell level Chemical state analysis in cell level→ → --XAFSXAFS

Cultivation of fern

As level in soil：481 µg g-1dry

T ： 3 kTerm：～ 3 weeks

Average As level ：～720 µg /gdry

arsenic-contaminated soil

As level*

i ：2800 4500 1dpinna：2800 - 4500 µg g-1drymidrib of a frond：84 - 250 µg /g dry

l di i i A* Anal. By AAS

culture medium containing As(1 ppm 4days)

X-ray energy As： 12.8keV-XRF, -XANES

In-vacuum undulator

Cd: 37.0keVBeam siz: ca. 1 m

XY slit (0.2 x 0.2 mm)Si 111 Monochromator

In vacuum undulator

XY slit (0.15 x 0.15 mm)K-B mirror

Sample53 m

SPring-8 BL37XUSample on XYstage

Sample

BEAMLINE DESCRIPTIONBEAMLINE DESCRIPTION Sample on XYstageX-ray

- BEAMLINE DESCRIPTION -The light source : In-vacuum type undulator

(Period length : 32 mm, the number of period : 140)Monochromator : Double-crystal monochromator

located 43 m from the source

- BEAMLINE DESCRIPTION -The light source : In-vacuum type undulator

(Period length : 32 mm, the number of period : 140)Monochromator : Double-crystal monochromator

located 43 m from the source

K B ifused quartz

platinum coated

12.8 keV37 keV[1]

fused quartzplatinum coated

MaterialSurface

Table Details of focusing optics by K-B mirror


12.8 keV37 keV[1]


MaterialSurface


12.8 keV37 keV[1]


MaterialSurface

Table Details of focusing optics by K-B mirror

detecorK-Bmirrorplatinum coated

250 mm100 mm0.8 mrad

platinum coated100 mm 50 mm2.8 mrad

SurfaceFocal length (1st mirror)

(2nd mirror)Average glancing angle

platinum coated250 mm100 mm0.8 mrad




platinum coated250 mm100 mm0.8 mrad




Instrument ~SPing-8 BL37XU~

X-ray

Detector

SDDSamplep

Acrylic plate (1 mm thick)

XRF imaging for As, K, and Ca of pinnae

Ａｓ

high

Aslow

KAs K

highAccumulation of As at Fertile with

spores along marginal parts

lowAs

Sample preparation for microbeam analysismoist unwoven paper

X-ray

vertical slicer

200m thick

vertical slicer (Model HS-1, JASCO Co.)

Mylar film Plastic plate

freeze dry of frozen

A section of pinna200200m

sporehigh

KAslow

KAs

frond

X-ray Energy : 14.999 keVX ray Energy : 14.999 keVBeam size : 50 m×50 mStep number : 35 point×90 pointmeasurement time : 1 sec/pointmeasurement time : 1 sec/point

X-ray Energy : 12.8 keVBeam size : 1.5 m ×1.5 mExposure time : 0.2 sec. / pointPoint : 150 point ×150 point －XRF imaging at SPring-8p p ag g at S g 8

555778 475

X-ray Energy : 12.8 keV

Ca0

As 0K

0

X ray Energy : 12.8 keVBeam size : 1.5 m ×1.5 mExposure time : 0.2 sec. / pointPoint : 150 point ×150 point

As level is low at spore

11730372

0

425

0As 0 Ca

0K

0

As K-dge XANES SporeAs

As(III) As(V)y

(a.u

.)

As

d In

tens

ity

paraphysis

sporangium

mar

lized paraphysis

==系列2=系列8

H3AsVO4AsIII2O3

Nor

m

As exits as As3+

prothallium系列8系列9系列7=系列5

prothallium

11855 11865 11875 11885As(V)Energy / eV

As200 m

Advanced properties of SR for XRF and XAFS analyses) i hl illi d i hl lli d ll l b1) Highly Brilliant and Highly collimated parallel beam







energy tunability (high energy) → XRF：element selective excitation

TmPositions of the L lines peaks of the heavy elements

4000

Sn Sb LaNd

DyTm

BiLu

Sr KRb K

Fe K

2000

Intens

ity

Rb K,Y K

Ni K

Ca K Ti K Fe K

Cu K

Ni K Pb LMn KK K

00 5 10 15 20

Energy/keV

Overlapping of heavy elements L lines with light elements K linesProblem of conventional XRF analysis (E<20 keV) →

Sample porcelain , Source：Mo K X-ray 40 kV-40 mA , time:1000sec

120

At

U

80

100eV

)Ｋα１

Ｋβ１

V

YbRe

HgAt

60

80

gy　

(Ke Ｌα１

Ｌβ１

rgy

/keV

Z Rh SnCs

NdTb

Yb

20

40

Ener

gEn

er

P Ca Mn Zn Br ZrZr Rh Sn Cs Nd Tb Yb Re Hg At U

0

20

0 10 20 30 40 50 60 70 80 90 1000 10 20 30 40 50 60 70 80 90 100

Atomic　NumberZ (Atomic Number)overlap

Fig.X-ray fluorescence energies of K & L lines v.s. atomic numberL lines for all elements < 20 keVAbove 20 keV → K line only →suitable for analysis of elements heavier than Rh K= 20.17 keV )

Apple leaves (NIST SRM 1515)

α -E Kα

Sr-Kα

Ba-

Kα-

Ba-

KLa

-Kα

Nd-

Kα※

ity/c

ps

NB

a-Kβ

Kβ

Yb-

Kα

＜cert. v.＞

Inte

nsi B

Kα

Nd-

KKα β Dy-

Kβ+

Y

α

Sr 25 ppmBa 49 ppmLa 20 ppm

e-Kα Sm

-K

Gd-

K

Gd-

Kβ D

Dy-

Kα pp

Ce 3 ppmNd 17 ppmSm 3 ppm

Energy /keV

※instrument(Pb) Ce Sm 3 ppm

Gd 3 ppmYb 0.3 ppm

32

Energy /keV

HE-SR-XRF at ＠SPring-8 BL08W

25 samples25 samples

SR

Detector

33Slit 200 µm×200 µm、meas. Time 600～2000 sec

Ｓ＆Ｗ Gunshot ResidueForensic application

Ch t i ti l t B Sb PbCharacteristic element: Ba,Sb, Pb

Ba

SbPb Pb

ＳＰｒing-８ＢＬ０８Ｗ

High energy SR-XRF characterization of trace gunshot residue

High energy XRF characterization of trace heavy elements in white car paints (paints A & B) compared with X-ray microprobe (bottom)

1500

ZnFeTi A 1000 Ti B1000

WTaSnNb

coun

ts

500 Nb

Zn

Ba

500

c 500 Nb

0 20 40 600

Energy(keV)0 20 40 60

0

Energy(keV)10000

Ti10000

Ti

5000

Ti

unts

5000

Ti

unts

EPMA EPMA

5000

SiAlFe

Cou 5000

Al

Cou

0 5 10 15 200

Energy(keV)0 5 10 15 20

0

Energy(keV) Ninomiya(２００４）

ConclusionLimitation of the SR-XRF

１．Microbeam analysis

i) the thickness of the sample should be in the order of beam size

→ preparation of thin sample is not easy

ii) it takes long hours to carry out two dimensional mapping

because of large numbers of measurement points

2. Low excitation efficiency for light elements

3. Special efforts is necessary to carry out quantitative analysis

4. Sample damage should be considered if you use brilliant Undulator SR Source or white X-ray radiation. Especially, care must be taken about photo-reduction/oxidation of the component elements.

H !However!

Attractiveness of (SR)-XRF１．Nondestructive analysis, multielemental analysis

2. Two dimensional resolution

3. Easy to carry out the analysis and easy to understand the results

4. Basic optical system for EDS analysis is simpleSR → Monochromator → sample → detector

５．We can analyze almost any sampleｓ

i f ll l l l i isize → from cell level to sculpture, paintings

in situ、 in vivo、 in air at any temperature

6 I f ti6. Information

concentration： major（％）, minor, trace（ppm) elements C ～Na ～ U

distribution: from nm level to cm leveldistribution: from nm level to cm level

chemical state ( oxidation state, local structure) C ～ Si ～ U

７ Multiple SR-X-ray analysis: combination with X-ray diffraction and７．Multiple SR-X-ray analysis: combination with X-ray diffraction and XAFS

ConclusionAttractiveness of SR-X-ray analyses１．Nondestructive multielemental analysis with cell level resolution

2. In vivo analysis in air is possible

Attractiveness of SR X ray analyses

y p

3. Information

concentration： major（％）, minor, trace（ppm) elements Na ～ U

distribution: from nm level to cm level

chemical state ( oxidation state, local structure) Al ～ U

New direction of SR-X-ray analyses for practical application

crystal structure & identification of crystalline phase

New direction of SR-X-ray analyses for practical application１．Combination of multiple techniques

XRF-XAFS-XRD from the same sampleXRF-XAFS-XRD from the same sample

2. Use of an automated sample system

130 diffraction data /day 100 SR-XRF data /day130 diffraction data /day 100 SR XRF data /day

ConclusionAttractiveness of SR-X-ray analysesAttractiveness of SR X ray analyses

X-ray is only electromagnetic wave which gives theinformation of chemical composition chemical stateinformation of chemical composition, chemical state,crystal structure, and internal structure(X-ray CT)from the same sample nondestructively with highfrom the same sample nondestructively with highspatial resolution.

X-ray fluorescence analysis X ray fluorescence analysis

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