cost-effective trace element analysis with txrf - bruker · cost-effective trace element analysis...

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Cost-effective Trace Element Analysis with TXRF

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Welcome

Your HostAlexander Seyfarth Product Manager XRFElemental & Process AnalysisBruker AXS

Today’s Topics• Introduction to XRF and

TXRF• The S2 PICOFOX

benchtop TXRF system• Why wait for sample

prep?• Application studies

• Environment• Medical/Pharma• Mining

• Summary• Interactive Q & A

Speakers

Dr. Michael Rider, Applications Scientist XRF, Madison, WI, USA

Dr. Armin Gross, Global Product Manager TXRF, Berlin, Germany

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Introduction to XRF and TXRF Michael Rider

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Principles of X-ray Fluorescence (XRF) Spectroscopy

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2

3 3

2

11. An X-ray quantum hits an inner

shell electron in a (sample) atom.The electron is removed leaving the atom in an excited state.

2. The missing inner shell electron is replaced by an electron from an outer shell.

3. The energy difference between the inner and outer shell is balanced by the emission of a photon quantum (fluorescence radiation).

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Principles of X-ray Fluorescence Spectroscopy

■ The energy, and therefore the wavelength, of the X-ray fluorescence radiation is characteristic for the different chemical elements.

QUALITATIVE ANALYSIS

■ The intensity of the X-ray fluorescence radiation is, in first approximation, proportional to the element concentration.

QUANTITATIVE ANALYSIS

Low z High z

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“Common” XRF optics

Beam angle: 45o / 45o

X-ray tube

Sample

Detector

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Samples for common XRF spectrometry (EDXRF and WDXRF):

■ Solids (cut, polished and put into suitable shape)■ Powders (as pressed pellets, fused beads or loose powders in

liquid cups)■ Liquids (in liquid cups)

Necessary sample amount: 1 - 10 g

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Principles of Total Reflection X-ray Fluorescence (TXRF) Spectroscopy

Total reflection X-ray fluorescence spectroscopy

Beam angle: 0o / 90o

X-ray tube

Detector

Sample carrier

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Principles of Total Reflection X-ray Fluorescence Spectroscopy

Samples:

Powders: direct preparation or as a suspension

Liquids: direct preparationAlways as a thin film, micro fragment

or suspension of a powderNecessary sample amount: Low µg /

µl range

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absorption of primary beamand fluorescence radiation

secondary fluorescenceenhancement

Quantification in common X-ray fluorescence spectroscopy

Ii = f ( ci , cj) and ci = f ( Ii , cj)


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Principles of Total Reflection X-ray Fluorescence Spectroscopy

Quantification in total reflection X-ray fluorescence spectroscopy

In TXRF the samples are prepared as thin films or layers.Therefore matrix effects are negligible

QUANTIFICATION IS POSSIBLE BY :■ Known concentration and net intensity of an internal standard element ■ Net intensity of element lines■ Sensitivity of the instrument for element lines (energy-dependent)

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Negligible absorption of primary beamand fluorescence radiation

Negligible secondary fluorescenceenhancement

Ii = f ( ci ) ci = f ( Ii )


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Setup and Working Principle of the S2 PICOFOX

X-ray source

MonochromatorDetector

SampleSample carrierSample changer

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The S2 PICOFOX

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Why Wait for Sample Prep! Michael Rider

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Please use your mouse to answer the question on your screen:

How do you currently treat your samples before analysis? (Check all that apply.)

No treatmentGrindingDissolvingDilutionExtractionDigestion

Audience Poll

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TXRF Sample Preparation Liquid Sample

Pipette 100 – 1000 µl of sample. Dilute if needed. Add single-element standard solution Homogenize

Transfer to sample carrierDry

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TXRF Sample Preparation Solid Sample −

Micro-particle

Grind if needed Use Q-tip to deposit on substrate

Add single-element internal standard solution (or skip if one element is known)Dry

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TXRF Sample Preparation Solid Sample −

Suspension

GrindWeigh out 20 – 50 mg Suspend in about 2.5 ml of suspension solution

Add single-element internal standard solutionPipette 10 µl of the suspension and dry

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TXRF Sample Preparation Digested Sample

Grind if neededWeigh out 20 – 50 mg

Digest sampleTransfer aliquot of sample Dilute if very high in mineral content

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TXRF Sample Preparation Digested Sample

Transfer to sample carrierDry

Pipette 100 – 1000 µl of sampleAdd single-element standard solutionHomogenize

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Environmental, Medical and Pharmaceutical Applications

Dr. Armin Gross

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S2 PICOFOX Application Overview

Environmental research and monitoring

Description of the application Benefit by TXRF

Sewage & fresh water analysis on-site analysisppb detection limitsfast and simple sample preparation

Aerosol analysis direct sampling on sample carrierdetection limits < 1 ng/m³

Filter analysis direct measurements (qualitatively)simple extraction for quantification

Contaminated soils on-site analysisscreening for contaminated hot spots

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Analytical task: Control of threshold values for heavy metals in:

raw and digested sewage samplesfresh water

Sample preparationdilution (raw sewage)remark: filtration and separate analysis of filtrate is possibleinternal standardizationpreparation (homogenization, vacuum drying) of 10 µl sample solution

Measurementmeasurement time: 1000 s

Application Sewage & Fresh Water Analysis

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0

0

1

10

100

1000

10000

0 0 1 10 100 1000 10000

ICP-OES values (mg/l)

TXR

F va

lues

(mg/

l)

digestedraw (undiluted)raw (diluted)

Results


Hg

Pb

Ni

Cu

Cr,Mn,Fe

S,P,K

Ca

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Detection limits

1000 s measurement time

standard configuration


ppb

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10

100

1000

0 10 20 30 40 50 60 70 80 90

Atomic number

Det

ectio

n lim

it (µ

g/l)

digestedraw

PITTCON 2008!PITTCON 2008!

“high efficiency module” for higher sensitivity 30 mm2 XFlash®

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S2 PICOFOX Application Overview

Medical and pharmaceutical


Blood, serum and urine ppb detection limitsfast and simple sample preparation

Impurities in nutrients/pharma comparable results than AAS simultaneous analysis

Authenticity element fingerprint ease of sample prep

“Heavy Metals” Analysis USP requirements (10 ppm) readily achievablemobile use

USP = US Pharmacopia

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S2 PICOFOX Blood, Serum, Urine and Peptides

Life science: Blood, serum and urine analysis

analysis of nutrition-relevant elements (Cu, Fe, Zn, Se)

analysis of other e.g. toxic elements and Pt (chemotherapy)

easy sample preparation

better stability compared to AAS and ICP-OES

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S2 PICOFOX Blood Analysis

Sample preparation:

Serum1:10 dilution with water (p.a. grade)Addition of Ga for internal standardization

Full blood1:1 dilution with water (p.a. grade)Addition of Ga for internal standardization

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Serum reference standards, diluted, measurement time: 600 s

10

100

1000

10000

10 100 1000 10000

TXRF values (µg/l)

Ref

eren

ce v

alue

s (µ

g/l)

FeCuZnSe

good correlation for Cu, Zn and Seoverestimation of Feimproved calibration curve required*

Remark: Confidence level of reference values is up to 35 % (!)

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Full blood reference standards, diluted, measurement time: 600 s

• application of optimized “blood calibration”

• Very good correlation for Fe, Cu, Zn, Se and others

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100

1000

10000

100000

1000000

10000000

10 100 1000 10000 100000 1000000 10000000

TXRF values (µg/l)

Ref

eren

ce v

alue

s (µ

g/l)

PSKCaRbSrPbSeCuZnFe

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Reproducibility

1): Sector-Field Inductively-Coupled Plasma Mass Spectroscopy2): Atomic Adsorption Spectroscopy

Serum (ClinCheck L2) Whole blood (Seronorm L2)

Element Unit TXRF s (n=5) Reference 1) s TXRF s (n=5) Reference 2) s

Fe mg/l 440 7,4 435 12 2,9 0,09 1,964 0,20

Cu µg/l 66 2,2 62 2,1 1685 43 1562 312

Zn µg/l 501 4,9 504 6,9 2194 118 2225 334

Se µg/l 12 0,29 12 1,0 97 18 102 26

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Example: Raw material NaCl

Analytical task: analysis of impurities, especially with regard to the limit value of 1 mg/kg for As, in pure NaCl

SamplesNaCl (p.a. grade), Carl Roth GmbH

As: < 0.4 mg/kgsame sample, spiked with As

Application Pharmaceutical Samples – Purity Control

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Application Pharmaceuticals - Purity Control

Recovery results:

y = 1,1157x + 0,0986R2 = 0,9972

0,0

1,0

2,0

3,0

4,0

5,0

0,0 1,0 2,0 3,0 4,0 5,0

Spiked As (mg/kg)

Mea

sure

d va

lues

As

(mg/

kg)

Trace element concentrations of Ca, Ti, Cr, Fe, Ni, Cu, Zn and Br were determined simultaneously

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Application Pharmaceuticals – Purity Control

Detection limits

600 sec

Conc. LLD

(mg/l)

Ca 2,4 0,57

Ti 1,8 0,25

Cr 0,85 0,17

Fe 11 0,13

Ni 0,29 0,09

Cu 0,34 0,08

Zn 0,33 0,07

As 1,2 0,07

Se (i.s.) 20 0,07

Br 19 0,08

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More Applications Alexander Seyfarth

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Application Reading Tea Leaves

Elemental content such as Pb, Tl, As and Cd is regulated to be less than 10 ppm

“organic” labeling might also imply that no preservation (fumigation) was performed

Inspection of the leaves by

a) Screening of pulverized materialb) Precision analysis on digested

material

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Application Food/Nutrients – Tea Leaves

Precision analysis on “hot” samples:Microwave digestion, digested solution measured both on TXRF and Graphite Furnace AAS

identical results for Pb with both techniquesTXRF found Br as well, indication of fumigated by methyl bromide

Screening for more than one element More determinations per sample for a service lab No calibration needed!

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Fortunes are made using exploration techniques:


PGE and indicator elements simple qualitative analysis direct or digested sample quantification ppb levels

mobile use in trailer

simultaneous determination

faster than AAS/ICP

S2 PICOFOX Digging for Gold

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S2 PICOFOX Exploration Samples

Analytical task: Check for trace elements in directly prepared sediment samples

Sample preparationfine grinding to less than 10 μm

internal standardizationmixingslurry prep on substrate

Measurementmeasurement time: 600 s

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S2 PICOFOX Exploration Samples

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S2 PICOFOX Au and Pt in Exploration

Good correlation between digested diluted, digested and raw samples

“Fit for purpose” choiceAqua regia or HNO3 digestions can be directly applied on the substrate and measured after drying

High loaded solutions can be diluted and measured“Fit for purpose” choice

Preparation can yield clues about the dissemination of the elements

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S2 PICOFOX CRM SARM7-B

Spike: 0 mg/kg

Spike: 10 mg/kg

Spike: 20 mg/kg

Spike: 30 mg/kg

Spike: 40 mg/kg

Ref.

(mg/kg) Conc.

(mg/kg) Conc.

(mg/kg) Conc.

(mg/kg) Conc.

(mg/kg) Conc.

(mg/kg) Pt 3.74 not det. 10.4 +/- 0.6 17.2 +/- 2.0 26.5 +/- 6.0 39.7 +/- 2.8 Au 0.27 not det. 12.6 +/- 1.5 17.2 +/- 1.2 29.6 +/- 1.9 46.3 +/- 11.6

Pt 3σ LLD 2.8 mg/kgAu 3σ LLD 1.5 mg/kg

Higher LLD due to high Zn matrix interference

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S2 PICOFOX CRM SARM7-B

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60 70

Spiked reference value (mg/kg)

TXR

F va

lue

(mg/

kg)

PtAu

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PGE Analysis After NiS Melt-Digestion

0,1

1

10

100

1000

10000

100000

0,1 1 10 100 1000 10000 100000

ICP-MS [µg/kg]

TXR

F [µ

g/kg

]

RhIrPtAu

geologicalsamples

automotivecatalysts

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S2 PICOFOX GEO applications

Suspensions can be tested for clay fraction “metal” loadingFractions can be measured based on density difference

Allows flotation recovery assessmentsOptimization of flotation

Trace element determination complimentary to majors and minor elements by WDXRFBrine and hydrothermal solutionsFluid Inclusion Brine analysis

For applications such as IODP IDDP System can be placed in mobile unit Operated in remote locations

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Task

determination of the element ratios inZnS-coated CdSe nanoparticles

Analytical challenges

R&D → only smallest (µg-range) sample amounts available need to reused!

demand for non-destructive analysis

sample material is almost insoluble: NO DIGESTION was possible

Application possible with TXRF!

No reference material!

Applications From Geo to Nano

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Results

Measured ratios of 3 samples versus target value ( )

S2 PICOFOX “Standardless” analysis

Application Characterization of Nanoparticles

Element Ratios of Nano Particles

Sample 2Sample 1

Sample 3

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1

4

0

2

4

6

8

10

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Zn/S Cd/Se Zn/Cd

Rat

io (w

t.-%

)

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Applications Summary - 3σ

Detection Limits

Low background ≈

low detection limits"ppt" "ppb" "ppm"

fresh water

sewage, mining sol.

soil

glass, wash coats

wine

food

pharma

blood, serum, urine

peptidesMeasurement time: 1000s

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Let’s Compare. . . Armin Gross

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Comparison TXRF versus AAS & ICP-OES

TXRF ICP-OES AAS

Direct analysis of solids

Qualitative, quantitative *

not possible GF-AAS only

Sample amount ng to µg range mg range mg range GF-AAS µg range

Sample types

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TXRF ICP-OES AAS

Multielement analysis

Yes Yes Sequential only

Standardless Yes (with restrictions)

Yes No

Meas. time 300 – 1000 s <10 s per element <10 s per element

Calibration Internal standardization

External, element- specific, to be

updated

External, element- specific, to be

updated


During operation

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TXRF ICP-OES AAS

Consumables (X-ray tube) (Nebulizer parts) Cathode lamps

Power consumption

Low (150 W) High (HF generator 2.5 – 3.6 kW)

Low

Water consumption

none > 0,5 l/min ~1.5 l/min (GF only)

Gas consumption

none Carrier/burning gas (Ar, N2 ), 15-20 l/min

FAAS: burning gas (C2 H2 ), 1.5-8 l/min

GF: Carrier gas (Ar,N2 )


Cost of operation

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The S2 PICOFOX can be an alternative to AAS and/or a

complement for existing ICP-OES systems

Major benefits of the S2 PICOFOX

flexibility with regard to sample types

easy multi-element analysis without external calibration

low maintenance and operating costs

small size of the system (mobile and remote location use)


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Any Questions?

Please type any questions you may have for any of our speakers in the Q&A box and then

click Send.

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Thank you for attending!

Please take a moment to complete the brief survey on your screen. Your feedback is very important to us.

Copies of this presentation and related TXRF resource materials will be emailed to you.

57 www.bruker-axs.com

Meet us at:SME: Feb.24-27 in Salt Lake City, UT

PITTCON: Mar 1-7 in New Orleans LA

TMS: Mar. 9-13 in New Orleans LA

IFT: June 28th-Jul 1st in New Orleans, LADenver X-ray Conference: Aug 4-8 in Denver, CO

XRF for YOU Seminar – NorthwestSeattle, Washington, Apr 25

A free 1-day seminar on theory, instrumentation, preparation and application of EDXRF and WDXRF

cost-effective trace element analysis with txrf - bruker · cost-effective trace element analysis...

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