Determination Of Mercury In Fish Research Articles

Application of magnetic graphene-based bucky gel as an efficient green sorbent for determination of mercury in fish and water samples

In this article, a highly efficient method based on coupling magnetic solid-phase extraction and dispersive microsolid-phase extraction was proposed to preconcentrate Hg2+. In this technique, extraction of Hg2+ was carried out by magnetic graphene-based bucky gel (MGBG). MGBG was prepared by dispersing magnetic graphene (MG) in a [Hmim][BF4]. Utilization of [Hmim][BF4] led to better dispersion of MG in aqueous solution and decreased the extraction time. In addition, MG was separable by an external magnet so filtration steps were omitted. The sorbent was characterized by X-ray diffraction, scanning electron microscopy, alternating gradient force magnetometer and Fourier transform infrared spectroscopy. The preconcentration conditions were optimized as pH value of 1 ± 0.2, dithizone concentration of 8 × 10−6 mol L−1, [Hmim][BF4] volume of 50 µL, MG amount of 5 mg, n-hexane volume of 200 µL and elution time of 5 min. The quantification of Hg2+ was carried out by UV–visible spectroscopy. Under the optimized conditions, limit of detection (2.11 μg L−1), relative standard deviation (2.59%), preconcentration factor (150) and linearity of dynamic range (7–100 μg L−1) were calculated which showed high reliability of sorbent to preconcentrate Hg2+. The effect of interference ions was investigated. The method was successfully applied to preconcentrate Hg2+ in fish and water samples. To better understand the adsorption of Hg2+ onto MGBG, thermodynamic of adsorption is reported.

Determination of mercury in fish by photochemical vapor generation graphite furnace atomic absorption spectrometry

Hg was determined in fish samples treated with TMAH, using n-propanol to assist the photochemical vapor generation.

Synthesis and application of ion-imprinted polymer nanoparticles for the extraction and preconcentration of mercury in water and food samples employing cold vapor atomic absorption spectrometry.

We describe a nanosized Hg(II)-imprinted polymer that was prepared from methacrylic acid as functional monomer, ethyleneglycol dimethacrylate as cross-linker, 2,2'-azobisisobutyronitrile (AIBN) as radical initiator, 2, 2'-di pyrydyl amine as a specific ligand, and Hg (II) as the template ions by precipitation polymerization method in methanol as the progeny solvent. Batch adsorption experiments were carried out as a function of pH, Hg (II) imprinted polymer amount, adsorption and desorption time, volume, and concentration of eluent. The synthesized polymer particles were characterized physically and morphologically by using infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopic techniques. The maximum adsorption capacity of the ion-imprinted and non-imprinted sorbent was 27.96 and 7.89 mg g(-1), respectively. Under optimal conditions, the detection limit for mercury was 0.01 μg L(-1) and the relative standard deviation was 3.2 % (n = 6) at the 1.00 μg L(-1). The procedure was applied to determination of mercury in fish and water samples with satisfactory results.

Validation of a hydride generation atomic absorption spectrometry methodology for determination of mercury in fish designed for application in the Brazilian national residue control plan

In the present study, a method for the determination of mercury (Hg) in fish was validated according to ISO/IEC 17025, INMETRO (Brazil), and more recent European recommendations (Commission Decision 2007/333/EC and 2002/657/EC) for implementation in the Brazilian Residue Control Plan (NRCP) in routine applications. The parameters evaluated in the validation were investigated in detail. The results obtained for limit of detection and quantification were respectively, 2.36 and 7.88 μg kg−1 of Hg. While the recovery varies between 90–96%. The coefficient of variation was of 4.06–8.94% for the repeatability. Furthermore, a comparison using an external proficiency testing scheme was realized. The results of method validated for the determination of the mercury in fish by Hydride generation atomic absorption spectrometry were considered suitable for implementation in routine analysis.

A new method for preconcentration and determination of mercury in fish, shellfish and saliva by cold vapour atomic absorption spectrometry

The development of a method using solid phase extraction for preconcentration and determination of mercury by cold vapour atomic absorption spectrometry is described. Hg (II) ions are sorbed on a minicolumn packed with Amberlite XAD-4 sorbent functionalised with 2-(2′-benzothiazolylazo)-p-cresol (BTAC). Then, a reducing solution was used for desorption and the transport of the analyte for subsequent detection. The assay presented a limit of detection of 0.011μgL−1 (0.011μgg−1, for solid samples), a limit of quantification of 0.038μgL−1 (0.038μgg−1, for solid samples), a precision of 0.50% (1.000μgL−1 Hg solution) and an enrichment factor of 46. The proposed method was applied to the determination of mercury in human saliva (0.055–0.200μgL−1). The following seafood collected in Todos os Santos Bay, Brazil was also analysed: bass (0.169–0.195μgg−1), mullet (0.043–0.361μgg−1), shrimp (0.075–0.374μgg−1) and mussel (0.206–0.397μgg−1).

Food Science Education Publications and Websites

Food Science Education Publications and Websites

Determination of Mercury in Fish: A Low-Cost Implementation of Cold-Vapor Atomic Absorbance for the Undergraduate Environmental Chemistry Laboratory

Mercury is a known neurotoxin that is particularly harmful to children and unborn fetuses. Consumption of contaminated fish is one major route of mercury exposure. This laboratory experiment gives students an opportunity to measure mercury concentrations in store-bought seafood and compare the results to suggested exposure limits. The U.S. Environmental Protection Agency (EPA) recommended method for determination of mercury concentrations is cold-vapor atomic spectroscopy. We propose a method of adapting an existing flame atomic absorbance spectrometer for this technique with little additional cost, thus allowing students to learn about this important technique. Students measured mercury concentrations in swordfish and tuna purchased at a local supermarket. Mercury levels in both fish were within the range found by the U.S. Food and Drug Administration (FDA). Students gained experience with sample digestion, cold-vapor analysis, and data analysis.

Determination of Total Mercury in Fish from Amur and Ussuri River of China by Microwave Digestion-ICP/MS Method

Determination of Total Mercury in Fish from Amur and Ussuri River of China by Microwave Digestion-ICP/MS Method

The relationship between the mercury concentration in fish muscles and scales/fins and its significance

AbstractThe determination of mercury in fish typically involves analysis of muscles. For predicting the concentration of mercury in fish muscle on the basis of the analysis of fish scales or fins, the relationship between total mercury concentrations in fish muscles and in fish scales and fins was studied. Mercury content in fish muscles, scales and fins was determined by atomic absorption spectrometry with thermal decomposition of the sample in a flow of oxygen. A number of scale treatments were applied in order to remove impurities and to enhance the prediction quality. For scale treatment, 40 min of washing with DI water in an ultrasonic bath is recommended. A coefficient of determination r2= 0.93 for the relationship between Hg concentrations in muscles and scales was achieved for 40 fish among the different fish species tested (European bream, perch, roach) from the Hamry Reservoir, Czech Republic. With respect to fin sampling, the coefficient of determination r2 for these fish was 0.86. The analysis of fish scales and caudal fins is a useful screening tool for assessing the relative mercury contamination of monitored fish. The method of sampling scales is not suitable for fish species with small scales such as brown trout.

Novo método espectrofotométrico para determinação de Hg (II) em amostras de peixe

A simple, sensitive and selective spectrophotmetric method is presented for the rapid determination of mercury (II) at trace levels using 2-mercapto-5-methylbenzimidazole (MMBI) as a new spectrophotometric reagent (lambdamax = 320 nm) in a slightly basic (0.04 M Britton-Robinson (BR) buffer, pH 8.0) aqueous solution. The reaction is instantaneous and the absorbance remains stable for over 24 hours. The average molar absorption coefficient was found to be 2.71 x 104 L mol-1 cm-1. The stoichiometric composition of the chelate is 1:1 (Hg:MMBI). Considerable excesses of copper, zinc, lead and cadmium do not interfere in the determination. The method developed allowed the determination of mercury in the range of 2 x 10-6 to 4 x 10-5 mol.L-1 with good precision, accuracy and the detection limit was 9.9 x 10-7 mol.L-1 of Hg. The method was successfully applied to fish samples and the results were evaluated and compared with classic atomic absorption spectrometry (AAS). The relative standard deviations for the samples analyzed were between 7.2 and 33% (n = 5), while the errors were between 1.63 and 11.6. The method was found to be sensitive, selective and was used for the determination of mercury in fish with satisfactory results.

Determination of Mercury in Fish by Isotope Dilution Inductively Coupled Plasma-Mass Spectrometry

A method for mild extraction and subsequent determination of total mercury content in fish by isotope dilution inductively coupled plasma-mass spectrometry (ID-ICP-MS) has been developed. The errors in the measurement of mercury isotope ratio were discussed. The dead time and mass bias induced by the system of ICP-MS were corrected by the use of lead isotopic certified reference material NIST SRM 981. The established method was validated by determining total mercury content in two certified reference materials, IAEA 436 (Tuna) and NRCC DOLT-3 (Dogfish Liver). The results of total mercury presented in IAEA 436 and DOLT-3 were 4.23 ± 0.06 and 3.33 ± 0.05 mg kg −1, respectively, which were in agreement with the certified values. The extraction method was suitable for the determination of mercury by ID-ICP-MS because the memory effect of mercury in the system could be efficiently eliminated.

Determination of Mercury in Fish by Cold Vapor Atomic Absorption Spectrophotometry Using a Multicommuted Flow Injection Analysis System

A flow system was developed for the determination of total mercury concentration in fish samples by cold vapor atomic absorption spectrophotometry (CVAAS), based on the multicommuted flow injection analysis (MCFIA) approach. The system uses independently controlled solenoid valves for the introduction of reagents and samples. When not injected, solutions were recirculating to the reservoir bottles, in this way reducing the waste produced by the analytical system and also the sample consumption. Results were compared to those obtained by the reference flow injection procedure. Accuracy was also assessed by recovery studies using a certified reference material as well as spiked samples; recovery percentages in the range of 90.7% to 99.8% were found. The repeatability of the method was better than 6.0% (RSD, n = 10). A limit of detection of 4.8 microg of mercury per kg of fresh fish sample was achieved. The total waste produced was reduced to 30% of that from the reference flow injection CVAAS procedure.

A low-cost non instrumental method for semiquantitative determination of mercury in fish.

A non instrumental method for the semiquantitative determination of mercury in fish is described. The sample is acid digested and the mercury vapor released after chemical reduction with SnCl2. The mercury vapor is then collected on a detecting paper covered with an emulsion of Cu2I2, 3% carboxymethylcellulose and MgCl2 as moistener agent. The colored Cu2[HgI4] complex is formed and the color intensity is proportional to the mercury concentration in the original sample. Parameters such as sample mass/digestion solution volume ratio, emulsion composition, paper covering technique, carrier gas flow were investigated. Comparative studies using CVAAS and digital color analysis after scanning the papers confirmed the applicability of the method to real samples.

Extraction-Fluorimetric Determination of Trace Amounts of Mercury by 1,10-Diaza-18-Crown-6 and Rose Bengal

A simple and sensitive extraction-fluorimetric method for the determination of mercury is reported. The method is based on the quantitative extractionof a ternary crown-mercury-rose Bengal complex into chloroform at pH 10 followed by fluorimetric measurements at 580 nm. A linear working range from 0.05 to 2.00 mg/mL is obtained. The relative standard deviation for 1.0 mg/mL mercury is 3.5%. The procedure was successfully applied to the determination of mercury in fish and mercurochrome.

Microwave dissolution for the determination of mercury in fish by cold vapour atomic absorption spectrometry

A procedure is described for the determination in fish species from the Mediterranean Spanish coast by cold vapour atomic absorption spectrometry. The samples were decomposed with nitric acid in a microwave acid digestion bomb. A certified reference sample was analysed and the results obtained agreed well with the certified values. The limit of detection for the samples investigated was 0.195 ng ml −1. The concentrations of mercury in fish ranged from 0.033 to 1.211 μg g −1.

Determination of mercury in fish using differential pulse anodic stripping voltammetry

Determination of mercury in fish using differential pulse anodic stripping voltammetry

Electron Capture Gas-Liquid Chromatographic Determination of Methyl Mercury in Fish and Shellfish: Collaborative Study

A method for determining methyl mercury in fish and shellfish was collaboratively studied in 8 laboratories. Methyl mercury is isolated from acetone-washed, homogenized tissue by adding hydrochloric acid and extracting into benzene the methyl mercuric chloride that is formed. The benzene extract is concentrated and analyzed for methyl mercuric chloride by electron capture gas-liquid chromatography on 5% DEGS-PS treated with inorganic mercuric chloride solution. The quantitation limit for the method is 0.05 micrograms Hg/g. Each collaborator determined methyl mercury at 2 levels in blind duplicate samples of swordfish, tuna, oyster, and shrimp tissues. Both fortified and unfortified samples were analyzed. Methyl-bound mercury in the samples ranged from 0.15 to 2.48 micrograms Hg/g. The reproducibility coefficients of variation for the 8 samples ranged from 3 to 13%. The accuracy, measured by comparison to reference values, ranged from 99 to 120%. Reference values were determined in the Associate Referee's laboratory by replicate analyses of the fortified and unfortified samples. The method has been adopted official first action.

The determination of mercury in fish

Abstract An acid digestion method followed by cold vapor atomic absorption spectrophotometry for the determination of mercury in fish is described. Sample portions are weighed into partial reflux tubes and digested with a H2SO4/HNO3 mixture. Hydrogen peroxide is added to facilitate complete destruction of organic matter. Sample digestion is performed using a Technico™ BD‐40 Block Digestor held at 265°C for up to 75 min. After digestion KMnO, is added to insure complete oxidation of Hg to Hg(II). Good precision and accuracy are observed based on replicate analyses of NBS reference materials and also spikes of CH3Hgcl solution added to fish tissue homogenates. The detection limit is 0.01 μg Hg/g fish tissue. The concentrations of Hg in fish collected from Wisconsin vaters have generally decreased since 1970 after a Hg discharge control program was initiated by the Wisconsin Department of Natural Resources.

Open Digestion Modification of AOAC Method for Determination of Mercury in Fish

The vanadium pentoxide-catalyzed reflux method has been modified to allow open digestion of samples in preparation for determination of organic and inorganic mercury. The reflux digestion performed with a bunsen burner resulted in charred samples, but digestions performed in tubes in a 95-100 degrees C water bath were satisfactory. As many as 40 digestions can be carried out simultaneously, and the technique offers a fast and simple approach to digestion, dilution, and transfer.

Rapid Digestion and Flameless Atomic Absorption Spectroscopy of Mercury in Fish: Collaborative Study

A collaborative study of the determination of mercury in fish has been completed in which wet oxidation of fish tissue in nitric acid, using vanadium as a catalyst, is compared with the AOAC official final action digestion technique, 25.103-25.105, involving a nitric-perchloric acid mixture. The study used tuna fish samples of known mercury content and included spike recovery studies in which methyl mercury solutions of known composition were provided to each laboratory. The study was designed to provide recovery information that bracketed the regulatory level of mercury in fish. The results indicate that the proposed digestion method is at least as precise and accurate as the AOAC method. The proposed method is also more rapid and less hazardous. It has been adopted as official first action.