The Benefits of TXRF for Ultra Trace Element Analysis

Innovation with Integrity

Dr. Armin GrossBruker Nano GmbH, Berlin, GermanyAugust, 2016

TXRF – How does it work?

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Principles of EDXRFBackground

Energy-Dispersive X-Ray Fluorescence (EDXRF) analysis works in a 45°/45°geometry• Energy of X-ray photons

Which element• Number of X-ray photons

Quantitative analysis

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Samples for common XRF spectrometry

• 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: from 1g to 10 g !!

Principles of EDXRFSamples

absorption of primary beamand fluorescence radiation

secondary fluorescenceenhancement

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

Concentration needs to be determinedwith matrix matched standardsDO YOU HAVE STANDARDS ???

Principles of EDXRFQuantification

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Principles TXRF spectroscopyFunctional principle

X-ray tube

monochromator

detector

sample disc

Total reflection X-ray fluorescence spectroscopy

• Samples must be prepared on a reflective media• Polished quartz glass or polyacrylic glass disc • Dried to a thin layer, or as a thin film or microparticle

Beam angle: 0o / 90o

1. excitation spectrum2. spectrum after prefiltration,

filter component invisible here3. emission spectrum of the tube4. X-ray tube5. monochromator6. monochromatized excitation

beam7. detector8. sample carrier

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Key to TXRF sensitivityHigh signal to low background

Monochromatization ofX-ray beam leads toalmost completereduction of background

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Negligible absorption of primary beam and fluorescence radiation

Negligible secondary fluorescence enhancement

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

Samples are prepared as thin films or layersmatrix effects are negligible

Principles TXRF spectroscopyMatrix effects

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iIS

ISiISi SN

SNCC

Ci: Element concentrationCIS: Internal standard concentrationNi: Element net countrateNIS: Internal standard net countrateSi: Element sensitivity factorSIS: Internal standard sensitivity factor

Element sensitivity

L-linesK-lines

Atomic number

Principles of TXRFQuantification

Lack of matrix effect allowseasy quantification by internal standardization

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Samples for TXRF• Powders: Direct preparation

or as suspension• Liquids: Direct preparation• Always as a thin film, micro fragment or

suspension of a powder• Necessary sample amount:

Low µg respectively µl range

Principles TXRFSamples

TXRF SpectrometerS2 PICOFOX

S2 PICOFOX – Compact TXRF

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• Most compact design portable, for on-site analysis

• Fixed excitation mode easy to use, mostsuitable for teaching

• >200 installations well established world wide technology

• Attractive pricing most valuable TXRFsolution

TXRF SpectrometerS4 TStar

S4 TStar – Advanced TXRF

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• Multiple excitation to detect most elements modes of the PSE

• Large area detectors improved sensitivity for lowest limits of detection

• Sample geometry measurement of discs, flexibility microscopy slides, wafers

• Motorized beam path automatic beam adjustment and QC procedures

• Large sample capacity up to 90 sample discs, multi-user operation

Rigaku Nanohunter II

• Benchtop model

• Mo X-ray tube, 600 W

• 16 samples capacity

GNR TX 2000• Floor-standing model

• Mo, W double target tube, 3 kW

• 12 samples capacity

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TXRF SpectrometerOther systems

Straight forward sample preparation

quartz glass glass carbon sapphire acrylic glass

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acrylic glass

quartz sapphire

glass carbon

Sample carrier

Quartz glass carriersdeliver lowest detectionlimits due to lowbackground

fill sample in micro tube

add internal standard

homogenize

Note: high matrix samples pipette on carriermay require a dilution step

You‘ll need just a few steps for the preparation of liquid samples

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Sample preparationLiquid and digested samples

dry by heat / vacuum

load the instrument

start data aquisition

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Sample preparationFinal steps

dilute sample with distilled water

add internal standard

homogenize

pipette on carrier

Suspensions can be analyzed just after dilution

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Sample preparationSuspensions

fill powder in mortar

grind carefully (<50 µm)

weigh about 20-50 mg

transfer to tube

Solids are ground to fine particle size and resuspended for direct analysis without digestion

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Sample preparationSolid and powder samples I

suspend in detergent solution

add standard

homogenize

pipette on carrier

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Sample preparationSolid and powder samples II

Sample preparationMicroparticles

dab vacuum grease on carrier

pick-up some particles with a (glass) rod

drop particles on grease

Microparticles are measured semi-quantitatively and non-destructively

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Current application areasTime for you to start with TXRF

Environmental /Ecology

Clinical Research / Biology Forensics Semiconductor

Nanoparticles Food/BeveragePharmaceutical/

Nutraceutical Plant Research

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www.facebook.com/groups/TXRFSpectrometry

eu.wiley.com/WileyCDA/WileyTitle/productCd-1118460278.html

www.s4tstar.com

www.s2picofox.com

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TXRFMore information required?