Atomic absorption spectrometric and colorimetric determination of iron in seafoods

Iron levels in 14 seafoods were determined by atomic absorption spectrometry (AAS) on freeze-dried composites. Samples were prepared for analysis after dry-ashing at 550 degrees C and wet digestion in HNO3-HClO4. Paired analysis of wet digests were accomplished by AAS and use of the colorimetric reagent, ferrozine. There was no significant difference in iron levels of seafoods due to sample preparation. While individual species levels were not significantly different between the AAS and colorimetric procedures, evaluation of all determinations indicates that ferrozine gives lower values (P less than 0.005) by 8%. Iron levels in seafoods in microgram/g dry weight (mg/100 g wet weight) determined by AAS on wet-digested samples were: 8 species of white finfish, 16.3 +/- 4.2 (0.31 +/- 0.08); Pacific shrimp, 12.3 +/- 1.4 (0.29 +/- 0.03); canned tuna, water pack, 16.6 +/- 2.9 (0.49 +/- 0.09); sockeye salmon, 29.0 +/- 5.5 (0.89 +/- 0.25); American shad, 29.1 +/- 1.5 (0.97 +/- 0.05); Pacific oysters, 391 +/- 45 (6.54 +/- 1.39); and Dungeness crab, 17.1 +/- 2.5 (0.35 +/- 0.05).