科研之友
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摘要
A simple and high throughput method suitable for routine determination of nickel in magnesium stearate (as pharmaceutical excipient) by GF-AAS with pyrolytic graphite coated tube transversely heated, after simple dissolution of the sample in acidified ethanol, without mineralisation, has been validated. The validation approach directly refers to linearity, detection and quantification limits, characteristic mass, selectivity (matrix effect), precision (repeatability and intermediate precision), accuracy and robustness. Linearity of response was verified for concentrations ranging from 0 to 12 ng/mL of nickel in standard solution in ethanol and was characterized by a correlation coefficient R of 0.9999. Detection limit of the proposed method was found to be 0.84 ng/mL (corresponding to 0.42 mu g/g of nickel in the real sample), and the quantification limit was 2.54 ng/mL (corresponding to 1.27 mu g/g of nickel in the real sample). The characteristic mass was m(o) = 13.62 +/- 0.67 pg of nickel. Repeatability and intermediate precision of the method are characterized by relative standard deviations ranging between 2.7 - 6.6% and 5.0 - 9.3%, respectively. Accuracy expressed as recovery gave values ranging between 98.6% and 100.5%. The overall recovery was 99.6%. The robustness was tested by varying the temperatures used for programming the graphite furnace stages and the experimental results were statistically compared through of F-test and Student t-test.
- 出版日期2012-11
