Infrared radiation as a heat source in sample preparation of shrimp for trace element analysis

An open sample preparation system based on use of infrared radiation (IR) for heating was used to accelerate the mineralization of shrimp samples to quantify their As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, Sn and V content by ICP-OES. The method presented good accuracy, as verified by analysis of NIST SRM 1566b oyster tissue, acceptable precision (< 20% RSD) and low RCC in the solutions (< 3 % w w(-1)). Optimal experimental conditions (1.0 g sample, 8 mL of HNO3, 8 min heating with a 500 W of lamp) were obtained using a full factorial design. The method was applied to whole harvested shrimp samples (with head, exoskeleton and viscera), which revealed levels of As (4.84 +/- 0.23 mg kg(-1)) and Cd (0.80 +/- 0.01 mg kg(-1)) above those allowed by Brazilian law. Sample preparation based on IR-assisted digestion provides a quick, simple and inexpensive alternative to conventional sample preparation techniques.