| Title: | Determination of mercury in fish otoliths by cold vapor generation inductively coupled plasma mass spectrometry (CVG-ICP-MS) |
| Author(s): | Kenduzler E; Ates M; Arslan Z; McHenry M; Tchounwou PB; |
| Address: | "Department of Chemistry and Biochemistry, Jackson State University, Jackson, MS 39217, USA" |
| DOI: | 10.1016/j.talanta.2012.02.063 |
| ISSN/ISBN: | 1873-3573 (Electronic) 0039-9140 (Print) 0039-9140 (Linking) |
| Abstract: | "A method based on cold vapor generation inductively coupled plasma mass spectrometry (CVG-ICP-MS) has been developed for determination of inorganic mercury, Hg(II), and total mercury in fish otoliths. Sodium borohydride (NaBH(4)) was used as the only reducing agent and its concentration was optimized across an acidity gradient to selectively reduce Hg(II) without affecting methylmercury, CH(3)Hg(I). Inorganic Hg was quantitatively reduced to elemental mercury (Hg(0)) with 1 x 10(-4)% (m/v) NaBH(4). CH(3)Hg(I) required a minimum of 0.5% (m/v) NaBH(4) for complete reduction. Increasing the HCl concentration of solution to 5% (v/v) improved the selectivity toward Hg(II) as it decreased the signals from CH(3)Hg(I) to baseline levels. Potassium ferricyanide solution was the most effective in eliminating the memory effects of Hg compared with a number of chelating and oxidizing agents, including EDTA, gold chloride, thiourea, cerium ammonium nitrate and 2-mercaptoethylamine chloride. The relative standard deviation (RSD) was less than 5% for 1.0 mug L(-1) Hg(II) solution. The detection limits were 4.2 and 6.4 ng L(-1) (ppt) for Hg(II) and total Hg, respectively. Sample dissolution conditions and recoveries were examined with ultra-pure CaCO(3) (99.99%) spiked with Hg(II) and CH(3)HgCl. Methylmercury was stable when dissolution was performed with up to 20% (v/v) HCl at 100 degrees C. Recoveries from spiked solutions were higher than 95% for both Hg(II) and CH(3)Hg(I). The method was applied to the determination of Hg(II) and total Hg concentrations in the otoliths of red emperor (CRM 22) and Pacific halibut. Total Hg concentration in the otoliths was 0.038 +/- 0.004 mug g(-1) for the red emperor and 0.021 +/- 0.003 mug g(-1) for the Pacific halibut. Inorganic Hg accounted for about 25% of total Hg indicating that Hg in the otoliths was predominantly organic mercury (e.g., methylmercury). However, as opposed to the bioaccumulation in tissues, methylmercury levels in otoliths was very low suggesting a different route of uptake, most likely through the deposition of methylmercury available in the water" |
| Keywords: | Animals Borohydrides/chemistry Calcium Carbonate/chemistry *Cold Temperature *Flounder Mass Spectrometry/*methods Mercury/*analysis Methylmercury Compounds/chemistry Otolithic Membrane/*chemistry *Perciformes Reducing Agents/chemistry Volatilization; |
| Notes: | "MedlineKenduzler, Erdal Ates, Mehmet Arslan, Zikri McHenry, Melanie Tchounwou, Paul B eng G12 MD007581-15/MD/NIMHD NIH HHS/ G12 RR013459/RR/NCRR NIH HHS/ G12RR013459/RR/NCRR NIH HHS/ Research Support, N.I.H., Extramural Netherlands 2012/04/10 Talanta. 2012 May 15; 93:404-10. doi: 10.1016/j.talanta.2012.02.063. Epub 2012 Mar 3" |
