January/February 2015

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SEPARATIONS AND PURIFICATIONS

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Element Ni 231.604

Ni 232.003 Cu 324.752 Cu 327.393 Zn 206.200 Zn 213.857 Fe 238.204 Fe 239.562 Mg 285.213 Mg 279.077 Sn 235.485 Sn 283.998 Pd 340.458 Pd 363.470 Pt 265.945 Pt 214.423 Ru 240.272 Ru 349.894

Slope 47104

19274

341672 257957 69827 31714

108575 70306

350687 20116 8165.9 6987.5 71003 33962 10566 7254.6 53678 50825

Intercept 8540.5

2599.7 51031 32622 53859 9583.9 18642 10370

174239 2077.6 172.27 345.7

1111.2 3728.9 1333

1016.6 640.32 4754.4

Table 4. Linear Regression Covering 0.05 µg/mL to 50.0 µg/mL Correlation Coeffi cient R2

0.9970 0.9998 0.9996 0.9997 0.9938 0.9992 0.9997 0.9998 0.9969 0.9999 0.9999 0.9999 1.0000 0.9999 0.9998 0.9998 1.0000 0.9999

0.047 0.054 0.052 0.052 0.054 0.051 0.053 0.052 0.052 0.046 0.046 0.052 0.408 0.051 0.054 0.051 0.053

Element

Ni 231.604 Ni 232.003 Cu 324.752 Cu 327.393 Zn 206.200 Zn 213.857 Fe 238.204 Fe 239.562

LOQ (µg/mL) % Recovery

0.051 0.047 0.054 0.052 0.052 0.054 0.051 0.053

Mg 285.213 0.052 Mg 279.077 0.052 Sn 235.485 Sn 283.998 Pd 340.458 Pd 363.470* Pt 265.945 Pt 214.423 Ru 240.272 Ru 349.894

0.046 0.046 0.052 0.408 0.051 0.054 0.051 0.053

102 94

108 104 104 108 102 106 104 104 92 92

104 82

102 103 102 106

Table 5. Quantitation Limits and Detection Limits for Each Trace Element Wavelength LOD (µg/mL)

LOQ (µg/g) based on 20-mg/mL Sample Preparation**

2.55 2.35 2.70 2.60 2.60 2.70 2.55 2.65 2.60 2.60 2.30 2.30 2.60

20.40 2.55 2.70 2.55 2.65

0.002 0.003 0.003 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.007 0.010 0.001 0.023 0.004 0.005 0.001 0.002

* Percent recovery for Pd 363.470 was calculated using 0.50 ppm level standard due to lack of sensitivity of 0.05 ppm level standard. ** Limit of quantitation for each specifi ed metal is based on sample size used.

alternative detection wavelength in case spectral interference is observed at the primary detection wavelength. This also aids in minimizing potential false positives. Table 4 shows the results of the linearity

40 | | January/February 2015

studies. The correlation coeffi cients were >0.99 for all elements of interest. Based on the results, the method is linear over the concentration range of 0.05 ppm to 50.0 ppm for all elements assessed.

Quantitation Limits and Detection Limits

In APIs, the metallic impurities are usually present at residual levels pushing the

0.10 0.15 0.02 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.35 0.50 0.05 1.15 0.20 0.25 0.05 0.10

Quantitative Limit (LQ) N = 3 Standard Deviation 0.051

0.0009 0.0005 0.0017 0.0013 0.0007 0.0008 0.0009 0.0005 0.0016 0.0017 0.0014 0.0020 0.0007 0.0056 0.0021 0.0026 0.0005 0.0002

LOD (µg/g) based on 20-mg/mL Sample Preparation

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