Statistical Evaluation of Cu, Mn and Zn Determinations in Biological Samples by Radiofrequency Capacitively Coupled Plasma Atomic Emission Spectrometry Using the Bland and Altman Test

Abstract.

This paper presents a statistical comparison of Cu, Mn and Zn determinations in biological samples by low power radiofrequency capacitively coupled Ar plasma (275 W; 27.12 MHz; 0.4 L min⁻¹ flow rate) atomic emission spectrometry and flame atomic absorption spectrometry using statistical analysis according to the Bland and Altman test and linear regression. For a content (µg g⁻¹ dry mass) of 5-43 Cu, 10-15800 Mn and 8-1100 Zn in fish fillet and freshwater molluscs, there was no significant bias in r.f.CCP-AES for a 95% confidence level. Certified reference materials were analysed by r.f.CCP-AES, and a good agreement between analysis results and certified values was obtained. Matrix effects of Ca and Na and their influence on the detection limits of Cu, Mn and Zn are presented for both methods. As compared to FAAS, r.f.CCP-AES is more prone to interferences and, consequently, the detection limits for Cu, Mn and Zn in biological samples (2; 2 and 3 µg g⁻¹ dry mass) are higher than those in FAAS. In spite of these problems, r.f.CCP-AES is capable of accurate and precise analyses of biological samples.