Comparison of the\nPerformance of ICP-MS, CV-ICP-OES,\nand TDA AAS in Determining Mercury in Marine Sediment Samples

Mercury (Hg) determination in marine sediment is an analytical\nchallenge due to the toxicity of this element even at low concentrations\n(up to 130 μg kg<sup>–1</sup> in marine sediments) and\ncomplex matrices. Therefore, it is necessary to use analytical techniques\nthat have high sensitivity, selectivity, and low limits of quantification\n(LoQ). In this study, two methods that require sample treatment and\none method with direct sampling were studied. The techniques studied\nwere inductively coupled plasma mass spectrometry (ICP-MS), inductively\ncoupled plasma optical emission spectrometry with cold vapor generation\n(CV-ICP-OES), and atomic absorption spectrometry with thermodecomposition\nand amalgamation (TDA AAS) for Hg determination in marine sediment\nsamples. Since ICP-MS has more studies in the literature, optimization\nwith design of experiments was developed for CV-ICP-OES and TDA AAS.\nAlthough it was found to have low levels of instrumental LoQ for all\nthree techniques, differences were found once the method LoQ was calculated.\nThe calculation for method LoQ considers all analytical procedures\nexecuted, including sample treatment, which provides a 100-fold dilution\nfor ICP-MS and CV-ICP-OES. The method LoQ obtained were 1.9, 165,\nand 0.35 μg kg<sup>–1</sup> for ICP-MS, CV-ICP-OES, and\nTDA AAS, respectively. Comparing marine sediment sample analyses,\nHg concentrations had no statistical difference when determined by\nICP-MS and TDA AAS. It was not possible to determine Hg in marine\nsediment samples by CV-ICP-OES due to the high method LoQ obtained\n(165 μg kg<sup>–1</sup>). Although ICP-MS has the advantage\nof being a multielemental technique, it is high-value equipment and\nneeds a large volume of argon, which has a high cost in the market,\nand it requires sample treatment. On the other hand, TDA AAS-based\nspectrometer DMA-80 performs direct sampling, avoiding the pretreatment\nstage, and has a relatively lower cost, both in terms of initial investment\nand maintenance, while maintaining the high sensitivity, accuracy,\nand precision required for Hg determination on marine sediment samples.