Application Note: 41632 Analysis of 18 Carat Gold Alloys ARL ADVANT'X Series with IntelliPower™ Sequential X-Ray Fluorescence Spectrometer

Introduction Key Words The Thermo Scientific ARL ADVANT'X • ARL ADVANT'X IntelliPower 3600 - 3600W sequential XRF • Gold spectrometer has been used to analyze 18 carat • X-Ray gold samples for gold, Fluorescence silver, copper and zinc. • XRF The ARL ADVANT’X has an optimized geometry and analytical configuration and offers high sensitivity and flexibility. Ease of operation is obtained through the state-of-the art WinXRF software. Figure 1: Calibration curve for GOLD with COLA correction. SEE = 0.0013 ‰

Analytical procedure The alloy samples were analyzed with a standard cassette having a 15 mm diameter aperture. A programmable aperture changer with elliptical mask of 15 mm was used to ensure that no radiation from the cassette face entered the detector. Chemical analyses were provided and used for the calibration of the instrument. Fundamental Parameter Alpha Coefficients are used to compensate for inter- element effects. Table 1 shows the measurement conditions for the elements determined.

ELEMENT LINE CRYSTAL DETECTOR

Au Lα LiF 200 SC Figure 2: Calibration curve for SILVER with COLA correction. SEE = 0.0051 ‰ Ag Kα LiF 200 SC Cu Kα LiF 200 SC Zn Kα LiF 200 SC

Table 1: Analytical conditions for gold alloy

Results Figures 1 to 4 show the calibration curves obtained for the elements gold, silver, copper and zinc with Fundamental Parameter Alpha corrections. Note that all data are in per thousands as is usual practice in the precious metals industry.

Figure 3: Calibration curve for COPPER with COLA correction. SEE = 0.0015 ‰ Conclusion In addition to these Base Curve with COmprehensive LAchance correction Analysis of 18 carat gold alloy for the elements gold, offices, Thermo Fisher SEE: 0.0074 ‰ silver, copper and zinc has been demonstrated. The Scientific maintains 24 results show that the ARL ADVANT'X IntelliPower 3600 a network of represen- 20 XRF is well suited to produce high precision results for tative organizations these elements. throughout the world. 16 It must be noted that the 15mm diameter aperture

Intensity (Kcps) 12 significantly reduces the performance in terms of precision. 8 Other versions of the ARL ADVANT'X with power levels of 1200 W and 2500 W exist as well. These versions 4 do not require an external water chiller. They can reach 0.4 0.8 1.2 1.6 2.0 Africa similar analytical results as shown in Table 2 with longer +43 1 333 5034 127 Concentration ‰ counting times (300s at 1200 W and 144s at 2500 W). Australia +61 2 8844 9500 Figure 4: Calibration curve for ZINC with COLA correction. SEE = 0.0074 ‰ Austria +43 1 333 50340 Precision tests on a gold alloy were carried out by Belgium +32 2 482 30 30 running the sample for ten repeat analyses with a counting Canada time of 100 sec. per element. The results are summarized +1 800 530 8447 in Table 2. China +86 10 5850 3588 RUN Au (‰) Ag (‰) Cu (‰) Zn (‰) Denmark 1 740.189 159.756 80.135 20.102 +45 70 23 62 60 2 740.052 159.988 80.045 20.072 Europe-Other +43 1 333 5034 127 3 740.140 159.947 80.026 20.087 France 4 740.086 159.854 80.033 20.085 +33 1 60 92 48 00 5 740.012 160.079 80.029 20.059 Germany +49 6103 408 1014 6 740.170 159.783 80.135 20.083 India 7 740.112 159.859 80.057 20.096 +91 22 6742 9434 8 740.097 159.929 80.051 20.091 Italy 9 740.134 159.783 80.067 20.051 +39 02 950 591 Japan 10 740.082 159.820 80.053 20.116 +81 45 453 9100 Latin America Avg. 740.107 159.880 80.063 20.084 +1 608 276 5659 SD 0.053 ‰ 0.104 ‰ 0.40 ‰ 0.019 ‰ Middle East +43 1 333 5034 127 Table 2: Repeatability for 18 carat gold sample using 15 mm diameter aperture Netherlands and a power of 3600 W +31 76 587 98 88 South Africa +27 11 570 1840 Spain +34 914 845 965 Sweden/Norway/ Finland +46 8 556 468 00 Switzerland +41 21 694 71 11 UK +44 1442 233555 USA +1 800 532 4752

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AN41632_E 12/07C

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