A clean up step of fat content previous to trace metal characterization in mussel tissues by inductively coupled plasma mass spectrometry

Inductively coupled plasma mass spectrometry analysis of trace and major elements of mussel tissues can be quickly and accurately analyzed after cleaning up the interfering fat content before the sample is digested in a microwave oven. Making use of experimental designs, the clean up procedure was achieved by the extraction of 1 g of freeze-dried tissue sample stirred with 5 ml of dichloromethane during five minutes. The microwave assisted digestion of the fat free samples was carried out with 0.2 g of tissue sample, 15 ml of 7.0% nitric acid with a power of 980 W during 18 min. The analytical method efficiency (accuracy and precision) was evaluated with a CRM: (NIST 2977, mussel tissue) and real mussel samples analyzed previously. The results confirmed the accuracy of the analysis by agreement with the previous results but the precision was significantly improved. The developed method allows operating routinely permitting to large numbers of samples to be quickly screened for trace metals.