Determination of copper and zinc in serum by derivative atomic absorption spectrometry using the microsampling technique

Abstract

A method has been developed for the determination of copper and zinc in the serum of rats by derivative microsampling flame atomic absorption spectrometry (D-MFAAS). The microsampling volume, solution uptake rate and other figures of merit of the proposed methodology were studied. For a 100 μl volume, the characteristic concentrations and detection limits (3s) of D-MFAAS were 0.023 and 0.013 μg ml⁻¹ for copper and 0.0066 and 0.0080 μg ml⁻¹ for zinc, which were 4.5–6.5-fold better than those of microsampling flame atomic absorption spectrometry (MFAAS). The detection limits and sensitivities of D-MFAAS were 6.4- and 16-fold for 300 μl volume for copper, 14- and 13-fold for 250 μl volume for zinc, better than those of MFAAS. The method demonstrates high tolerance to interferences, and the analytical results obtained for a certified reference material, GBW 08551 Pork Liver, were in good agreement with the certified values. The recovery with the standard additions method was good, in the range 97.6–101.5%, and precisions (relative standard deviations) obtained for a diluent sample containing 0.5 μg ml⁻¹ copper and 0.7 μg ml⁻¹ zinc were 4.0% and 3.5% (n = 15) for copper and zinc, respectively.