Determination of Cadmium, Nickel, Lead, and Zinc in Fish Tissue by Flame and Graphite Furnace Atomic Absorption after Extraction with Pyrrolidine Dithiocarbamate and Activated Carbon

Abstract

A solid phase extraction (SPE) technique using an activated carbon column was developed for the extraction of trace levels of Cd, Ni, Pb, and Zn in aqueous solution which was obtained from the digestion of fish tissue. Ammonium pyrrolidin edithiocarbamate (APDC) was used to form metallic complexes that could be retained in a SPE column which was packed with powder activated carbon. The analytes were eluted from the column by nitric acid in acetone. The metal concentrations were determined by flame and graphite atomic absorption spectroscopy. The effects of flow rate, APDC concentration, and pH were investigated. The proposed method was validated. The method detection limits were 11.7, 13.4, 10.1, and 25.3 µg kg⁻¹ for Cd, Ni, Pb, and Zn, respectively. The recoveries and RSDs were within the range of 81.9–101.1% and 0.6–6.0%, respectively. The method has potential merit for heavy metal determination in fish tissue.

Keywords:

• AAS
• Activated carbon
• Asian sea bass
• Heavy metal
• Pyrrolidine dithiocarbamate

Acknowledgments

This study was carried out in the Environmental Analysis Research Unit (EARU) financially supported by The Integration Project: Innovations for the Improvement of Food Safety and Food Quality for New World Economy, Government Research Budget, Chulalongkorn University.

Notes

^a chemical modifier; 0.05 mg NH₄H₂PO₄ + 0.003 mg Mg(NO₃)₂.

^a Mean value (range), n = 2.

^b Mean value ± SD, n = 11.

^a Mean value (range), n = 2.

^b Mean value ± SD, n = 3; n.d. = not detectable.

^a Mean value ± SD, n = 4.