www.bam.de

Jochen V.

Maren K.

Dorit B.

Pranee P.

Quantification of in copper metals sulfurand its alloys by ICP-IDMS

1,2,3 1 1 1,2P. Phukphatthanachai , J. Vogl , N. Jakubowski , U. Panne1BAM Federal Institute for Materials Research and Testing, Berlin, Germany2Humboldt University, Berlin, Germany3National Institute of Metrology (Thailand), Pathum Thani, Thailand

Requirement

SApplications: Certification of reference materials

Purity assessment

Reference value assignment for inter-laboratory comparisons

Calibration of other analytical methods

9. Matrix removal efficiency 99.999 %

Sulfur recovery > 80 %

8. Separation 3: Chelating resin

(Chelex-100)

More detail: JAAS, 2017, DOI: 10.1039/C7JA00338B

10. Instrument: Element 2

(Thermo-Fisher Scientific)

- Medium resolution > 4000

- Ni sampler and skimmer X-cone-1- Background 30-48 ng·g

7 32 -1- Sensitivity 1x10 for S cps/(µg·g )

7. Separation 2: Strong anion exchange resin

(AG1X8)

6. Separation 1: Cation exchange resin

(CG50)

5. Digestion:34- Spike isotope: S

- Dissolution in nitric acid - Digestion in high pressure asher (HNO + H O )3 2 2

2. Copper: essential and

important to industy

INT

RO

DU

CT

ION

EX

PE

RIM

EN

T:

sulf

ur-

mat

rix

sep

arat

ion

RE

SU

LTS

AN

D C

ON

CLU

SIO

N

CuSIsotope composition

(IUPAC 2000)32 S 0.9499(26)33 S 0.0075(2)34 S 0.0425(24)36 S 0.0001(1)

16

32.065

3.Sulfur:

a key factor in quality of copper metals and its alloys

Ion

inte

nsi

ty (

arb.

un

its) Sample Spike

32S 32S34S 34S

Ion

inte

nsi

ty (

arb.

un

its)

32S34

S

Sample blend

clear solution

weak cation resin (CG50)

before after

w = w M m (R - R ) - ProcBlankx yb x y y xy

M m a (R - R ) mb x xb xy x x

w = mass fraction of sulfur in the sample (mg )x

-1·g

w = mass fraction of sulfur in the spike (mg ) yb

-1·g

M = standard atomic weight of sulfur in samplex

M = atomic weight of spike isotopeb

a = abundance of spike isotope in samplexb

m = mass of sample (g)x

m = mass of spike (g)y

R = isotope ratio in samplex

R = isotope ratio in spikey

R = isotope ratio in sample blendxy

ProcBlank = procedure blank (mg)11. IDMS equation

1. Limitations of current techniques: Lack of metrological traceability

Inconsistent results

High relative measurement

uncertainty (> 5 %)

High background

Polyatomic interferences

High detection limit

High matrix concentration

4. IDMS (Isotope Dilution Mass Spectrometry)

- High accuracy- Metrological traceability- Small measurement uncertainty

- High accuracy

- Traceable to SI

- Small measurement uncertainty

<1 % RMU

- High matrix removal efficiency 99.999 %

- High sulfur recovery > 80 %

- Low procedure blank (4-53 ng)

- LOD 0.2 -1 -1µg·g , LOQ 0.54 µg·g

- Working range (15-1500 )-1µg·g

12. Results (sulfur in copper CRMs)

SI

Mass fraction of sulfur in copper samples, ICP-IDMS

Secondary calibrator, 34S isotope standard, IDMS

Primary calibrator, NIST3154, gravimetric and coulometric titration

List BAM-M385 BAM-M376a BAM-228 BAM-227 NIST SRM494

-1measured value (µg·g ) (37.7 ± 0.2) (133.6 ± 0.9) (385.5 ± 2.4) (1,376.6±0.1) (14.3±0.1)

U (%)rel 0.5 0.6 0.6 0.5 0.7

-1reference value (µg·g ) (31.2 ± 1.5) (133 ± 19) 360 ± 40 1,220±100 (15 ± 3)

-1Cu remaining (ng·g ) < 100 < 150 < 100 < 150 < 150

number of replicates 8 8 8 8 4

13. Conclusion