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Crowther ER, Demers JD, Blum JD, Brooks SC, Johnson MW. Coupling of nitric acid digestion and anion-exchange resin separation for the determination of methylmercury isotopic composition within organisms. Anal Bioanal Chem 2023; 415:759-774. [PMID: 36472636 DOI: 10.1007/s00216-022-04468-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 11/19/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022]
Abstract
Isotope ratios of methylmercury (MeHg) within organisms can be used to identify sources of MeHg that have accumulated in food webs, but these isotopic compositions are masked in organisms at lower trophic levels by the presence of inorganic mercury (iHg). To facilitate measurement of MeHg isotope ratios in organisms, we developed a method of extracting and isolating MeHg from fish and aquatic invertebrates for compound-specific isotopic analysis involving nitric acid digestion, batch anion-exchange resin separation, and pre-concentration by purge and trap. Recovery of MeHg was quantified after each step in the procedure, and the average cumulative recovery of MeHg was 93.4 ± 2.9% (1 SD, n = 28) for biological reference materials and natural biota samples and 96.9 ± 1.8% (1 SD, n = 5) for aqueous MeHgCl standards. The amount of iHg impurities was also quantified after each step, and the average MeHg purity was 97.8 ± 4.3% (1 SD, n = 28) across all reference materials and natural biota samples after the final separation step. Measured MeHg isotopic compositions of reference materials agreed with literature values obtained using other MeHg separation techniques, and MeHg isotope ratios of aqueous standards, reference materials, and natural biota samples were reproducible. On average, the reproducibility associated with reference material process replicates (2 SD) was 0.10‰ for δ202MeHg and 0.04‰ for Δ199MeHg. This new method provides a streamlined, reliable technique that utilizes a single sample aliquot for MeHg concentration and isotopic analysis. This promotes a tight coupling between MeHg concentration, %MeHg, and Hg isotopic composition, which may be especially beneficial for studying complex food webs with multiple isotopically distinct sources of iHg and/or MeHg.
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Affiliation(s)
- Elizabeth R Crowther
- Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI, 48109-1005, USA.
| | - Jason D Demers
- Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI, 48109-1005, USA
- Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, 8 College Rd., Durham, NH, 03824-2600, USA
| | - Joel D Blum
- Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI, 48109-1005, USA
| | - Scott C Brooks
- Environmental Science Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37831-6038, USA
| | - Marcus W Johnson
- Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI, 48109-1005, USA
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Valsecchi L, Roscioli C, Schiavon A, Marziali L. Methylmercury determination in freshwater biota and sediments: Static headspace GC-MS compared to direct mercury analyzer. MethodsX 2022; 8:101581. [PMID: 35004215 PMCID: PMC8720905 DOI: 10.1016/j.mex.2021.101581] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/13/2021] [Indexed: 11/29/2022] Open
Abstract
We developed and compared two analytical methods for determination of MeHg in freshwater biota and sediments, by: I) simplified static headspace GC-MS using internal standard (IS) isotope dilution quantification, after microwave acid digestion and aqueous phase NaBEt4 ethylation; II) Automated Mercury Analyzer, after double toluene extraction followed by back-extraction with L-cystein. The performance was evaluated by analysis of certified reference materials. For biota, mean recovery was 100 ± 2% and relative standard deviation (RSD) ≤ 6.8% for method I, and mean recovery was 98 ± 7% and RSD ≤13% for method II. For sediments, recovery of 94.5% and RSD of 8.8% were obtained with method I, and recovery of 90.3% and RSD of 9.4% with method II. Limits of detection (LOD) were 0.7 µg kg−1 and 6 µg kg−1, respectively. Both techniques were tested for MeHg analysis in freshwater invertebrates, fish and sediments, covering a large range of MeHg values (1.9–670 µg kg−1 d.w.). • Both protocols proved to be suitable for MeHg analysis in complex environmental matrices, even if, for method II, interferences in the extraction phase and limited sensitivity may hinder sediment analysis. • Passing-Bablock regression revealed a slight disproportion between methods, with line slope = 1.058 (95% CI ranging from 1.001 to 1.090).
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Affiliation(s)
- Lucia Valsecchi
- CNR-IRSA National Research Council, Water Research Institute, Via del Mulino 19, Brugherio (MB) I-20861, Italy
| | - Claudio Roscioli
- CNR-IRSA National Research Council, Water Research Institute, Via del Mulino 19, Brugherio (MB) I-20861, Italy
| | - Alfredo Schiavon
- CNR-IRSA National Research Council, Water Research Institute, Via del Mulino 19, Brugherio (MB) I-20861, Italy.,Department of Ecohydrology, IGB Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin 12587, Germany
| | - Laura Marziali
- CNR-IRSA National Research Council, Water Research Institute, Via del Mulino 19, Brugherio (MB) I-20861, Italy
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Artavia G, Cortés-Herrera C, Granados-Chinchilla F. Selected Instrumental Techniques Applied in Food and Feed: Quality, Safety and Adulteration Analysis. Foods 2021; 10:1081. [PMID: 34068197 PMCID: PMC8152966 DOI: 10.3390/foods10051081] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/13/2021] [Accepted: 03/19/2021] [Indexed: 12/28/2022] Open
Abstract
This review presents an overall glance at selected instrumental analytical techniques and methods used in food analysis, focusing on their primary food science research applications. The methods described represent approaches that have already been developed or are currently being implemented in our laboratories. Some techniques are widespread and well known and hence we will focus only in very specific examples, whilst the relatively less common techniques applied in food science are covered in a wider fashion. We made a particular emphasis on the works published on this topic in the last five years. When appropriate, we referred the reader to specialized reports highlighting each technique's principle and focused on said technologies' applications in the food analysis field. Each example forwarded will consider the advantages and limitations of the application. Certain study cases will typify that several of the techniques mentioned are used simultaneously to resolve an issue, support novel data, or gather further information from the food sample.
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Affiliation(s)
- Graciela Artavia
- Centro Nacional de Ciencia y Tecnología de Alimentos, Sede Rodrigo Facio, Universidad de Costa Rica, San José 11501-2060, Costa Rica;
| | - Carolina Cortés-Herrera
- Centro Nacional de Ciencia y Tecnología de Alimentos, Sede Rodrigo Facio, Universidad de Costa Rica, San José 11501-2060, Costa Rica;
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Probabilistic Estimation of Dietary Intake of Methylmercury from Fish in Japan. Food Saf (Tokyo) 2021; 9:1-9. [PMID: 33791185 PMCID: PMC8008453 DOI: 10.14252/foodsafetyfscj.d-20-00018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 12/18/2020] [Indexed: 12/04/2022] Open
Abstract
Dietary intake of methylmercury from fish was estimated via Monte Carlo simulation using data for methylmercury concentrations in 210 fish samples and data regarding fish consumption extracted from the Japanese National Health and Nutrition Survey. The fish analyzed were classified into 5 groups according to categories used in the survey. The distribution of consumption of fish from each group was used without fitting to statistical distributions. A log-normal distribution was fitted to the distribution of methylmercury concentration in each fish group. Two random numbers that followed these distributions were generated, and a trial value was calculated by multiplying these random numbers. The trial value was divided by the body weight (50 kg) to arrive at an estimate of dietary methylmercury intake. A total of 100,000 Monte Carlo simulation iterations were performed. The estimated mean daily intake of methylmercury was 0.093 µg/kg body weight (bw)/day. This value is well below the tolerable daily intake of 0.292 µg/kg bw/day calculated from the tolerable weekly intake (2.0 µg/kg bw/week) established by the Food Safety Commission of Japan. The probability that the daily intake of methylmercury exceeds the tolerable daily intake was 7.6%. As there are no data regarding fish consumption for consecutive days, estimation of the weekly intake of methylmercury is a subject for future studies.
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Kakimoto S, Yoshimitsu M, Akutsu K, Kiyota K, Fujiwara T, Watanabe T, Kajimura K, Yamano T. Concentrations of total mercury and methylmercury in red snow crabs (Chionoecetes japonicus) caught off the coast of Japan. MARINE POLLUTION BULLETIN 2019; 145:1-4. [PMID: 31590765 DOI: 10.1016/j.marpolbul.2019.04.062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 04/24/2019] [Accepted: 04/25/2019] [Indexed: 06/10/2023]
Abstract
The total mercury (T-Hg) and methylmercury (MeHg) concentrations in red snow crabs (Chionoecetes japonicus) caught off the coast of Japan were analyzed. The T-Hg concentration ranged from 0.03 to 0.56 mg/kg (mean: 0.21 mg/kg) in the raw muscle, and 0.02 to 0.74 mg/kg (mean: 0.27 mg/kg) in the boiled muscle. The MeHg concentration ranged from 0.04 to 0.54 mg/kg (mean: 0.20 mg/kg) in the raw muscle. The mean ratio of MeHg to T-Hg was 0.88. The crab body weight was found to significantly correlate with the concentrations of T-Hg (r = 0.488) and MeHg (r = 0.490) (p ≤ 0.01). For the general population in Japan, the intake of MeHg from eating red snow crab was estimated to be lower than 0.013 mg/week, which was less than one-sixth of the tolerable MeHg intake (0.08 mg/week).
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Affiliation(s)
- Sachiko Kakimoto
- Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka City, Osaka 537-0025, Japan.
| | - Masato Yoshimitsu
- Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka City, Osaka 537-0025, Japan
| | - Kazuhiko Akutsu
- Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka City, Osaka 537-0025, Japan
| | - Kyohei Kiyota
- Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka City, Osaka 537-0025, Japan
| | - Takuya Fujiwara
- Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka City, Osaka 537-0025, Japan
| | - Takahiro Watanabe
- National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki City, Kanagawa 210-9501, Japan
| | - Keiji Kajimura
- Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka City, Osaka 537-0025, Japan
| | - Tetsuo Yamano
- Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka City, Osaka 537-0025, Japan
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Watanabe T, Hayashi T, Matsuda R, Akiyama H, Teshima R. Surveillance of Total Mercury and Methylmercury Concentrations in Retail Fish. Food Hygiene and Safety Science (Shokuhin Eiseigaku Zasshi) 2017; 58:80-85. [PMID: 28484136 DOI: 10.3358/shokueishi.58.80] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Most fish samples contain methylmercury, that the concentrations very greatly according to the fish species. To avoid the adverse health effects of methylmercury while retaining the benefits provided by fish consumption, it is important to select suitable fish species and to control the amount of the fish intake. We surveyed the concentrations of total mercury and methylmercury in 210 retail fish samples classified into 19 fish species by using validated analytical methods. The results of this survey were as follows. The total mercury and methylmercury concentrations were higher than 1 mg/kg in some samples of swordfish and bluefin tuna, which are large predatory fish species. In bluefin tuna and yellowtail, total mercury and methylmercury concentrations in farm-raised fish were lower than those in natural fish. There was a positive correlation between total mercury concentration and methylmercury concentration. Our results indicate that a cut-off value of 0.3 mg/kg total mercury in the screening of fish samples would increase the effectiveness of inspection.
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