Determination of total arsenic in fish by hydride-generation atomic absorption spectrometry: method validation, traceability and uncertainty evaluation (original) (raw)
Related papers
Microchemical Journal, 2006
Simple and rapid analytical procedures for the determination of Hg 2+ and methylmercury in fish were proposed after careful optimization of chemical and instrumental parameters for Hg measurement by cold vapor (CV)/hydride generation (HG) atomic absorption spectrometry (AAS) and CV/HG inductively coupled plasma atomic emission spectrometry (ICP-AES). Quantitative extraction of Hg species avoiding any interspecies conversion was achieved by fast microwave assisted solubilization of fish tissue with relatively low amount of tetramethylammonium hydroxide (TMAH) or 6 mol L − 1 HCl. After careful optimization of chemical parameters selective determination of Hg 2+ in the presence of excess of methylmercury is attained by using continuous flow CV AAS, 1% m/V SnCl 2 as reductant and 0.1 mol L − 1 HCl as reaction medium. Simple calibration curve prepared with aqueous standard of Hg 2+ is recommended for its quantification. Both Hg 2+ and methylmercury could be determined simultaneously with equal sensitivity by CV/HG ICP-AES directly in the diluted TMAH solution obtained after extraction with 1% m/ V NaBH 4 as reductant. Quantification of the sum of Hg 2+ and methylmercury against calibration curve prepared with aqueous standard of methylmercury is suggested. It should be mentioned that batch hydride generation system with quartz tube heated in air/acetylene flame could also be used for simultaneous determination of both Hg species in fish extracts, with standard additions calibration. The validity of the developed analytical procedures for selective determination of Hg 2+ and methylmercury (by difference between the total Hg and Hg 2+ ) is confirmed by the analyses of certified reference material DOLT-1 and reference material IMEP-20. Very close agreement between certified values and analytical results was found.
Molecules, 2019
Analytical methods for the determination of total arsenic (TAs) and arsenic species (arsenite—As(III), arsenate—As(V), monomethylarsenic acid—MMA, dimethylarsenic acid—DMA and arsenobetaine—AsB) in freshwater fish samples were developed. Inductively coupled plasma mass spectrometry with dynamic reaction cell (ICP-DRC-MS) and high-performance liquid chromatography hyphenated to ICP-DRC-MS were used for TAs and arsenic species determination, respectively. The DRC with oxygen as a reaction gas was used. Sample preparation, digestion, and extraction were optimized. Microwave assisted digestion and extraction provided good recovery and extraction efficiency. Arsenic species were fully separated in 8 min using 10 mmol L−1 of ammonium dihydrogen phosphate and 10 mmol L−1 of ammonium nitrate. Overlapping of AsB and As(III) of arsenic species in the presence of a high concentration of AsB and trace amounts of As(III) were studied. Detailed validation of analytical procedures proved the relia...
Food Chemistry, 2009
The aim of the study was to evaluate total arsenic (As) in five tissues (gills, mouthpiece, intestine, liver and muscles) of 10 fish species caught from As contaminated Manchar Lake (26°3 0 N: 67°6 0 E) Sindh Pakistan during 2006-2007. The total As concentration was determined by hydride generation atomic absorption spectrometry (HG-AAS), prior to microwave assisted acid digestion. The certified reference material DORM-2 (dogfish muscle) was used to check the quality control of the technique. The good agreement with the certified value at 95% confidence limit confirmed the validity of As determination method. The limit of detection (LOD) and limit of quantitation (LOQ) of As were 0.034 and 0.11 lg/g, respectively. The As concentration ranges in different tissues were obtained as: gills (1.01-10.4), mouth pieces (1.01-18.6), intestine (1.01-11.2), liver (3.51-10.9) and in muscles (2.12-15.2) lg/g on dried basis. The bioaccumulation factor (BAF) for As in fish muscles were found in two ranges (4.88-7.2) and (17.6-35.3). The contribution of the daily intake of As, based on the consumption of 250 g fresh fish muscles per day was found in the range of 0.1-0.76 lg, higher than WHO tolerable limit.
Determination of Arsenic in Food Samples by Hydride GenerationAtomic Absorption Spectrometry
Microchimica Acta, 2004
A method for the determination of trace amounts of arsenic in food samples using flow injection analysis and atomic absorption spectrometry with hydride generation (FI-HG AAS) was developed. The parameters of the flow injection system and the hydride generation were optimized with respect to reagent concentrations, atomization temperature, injection volume, reaction coil length and carrier flow rate. The limits of detection and quantification were 0.34 mg L À1 and 1.2 mg L À1 , respectively, and the analytical curve is linear up to 30.0 mg L À1 arsenic. The relative standard deviation for 12 replicates varies between 5% for 4.0 mg L À1 As and 1.8% for 30.0 mg L À1 As, with an injection frequency of up to 135 h À1. Interferences from Ni(II), Cu(II), Fe(III), Cr(III), Mo(II), Bi(III), Se(IV), Se(VI), Sb(III) and Sb(V) could be masked with a mixture of ascorbic acid-KI in a 5.0 mol L À1 HCl solution. The accuracy of the proposed method was evaluated by using certified reference materials of biological samples, and the method was used to determine the content of arsenic in fish and coffee beans.
2014
Abstract-- This research was done to compare two different types of method in measuring the total arsenic using hydride generator quartz cell AAS (HG-QFAAS) and inductively coupled plasma mass spectrometry (ICP-MS) measurement. These methods were validated using CRM DORM-2 ([As] =18.0 µg g-1 ±1.1 µg g-1, found 17.7 µg g-1 ± 0.9 µg g-1; n = 3) and DORM-3 ([As]=6.88 µg g-1 ± 0.3 µg g-1, found 6.77 µg g-1 ±0.14 µg g-1; n = 3). The result of this study showed that ICP-MS measurement was more accurate compared to HG-QFAAS measurement. However, measurement by ICP-MS is more expensive than HG-QFAAS. The result of this research can be used as a reference method for determination of total arsenic in tuna fish sample by HG-QFAAS. Index Term-- DORM-2, DORM-3, HG-QFAAS, ICP-MS, total arsenic, tuna fish 1.
Hazardous impact of arsenic on tissues of same fish species collected from two ecosystem
Journal of Hazardous Materials, 2009
The purpose of this paper is to develop a database of fish tissues and to evaluate concentration of arsenic (As) in five tissues of fish species collected from Manchar Lake Pakistan and to compare concentration of As in fish tissues of same fish species collected from the Indus River, Pakistan. A sensitive and precise, hydride generation atomic absorption spectrometry (HG AAS) method is presented for the determination of total Arsenic (As). Microwave acid-assisted digestion (MAD) procedure based on the mixture HNO3/H2O2 was evaluated. The method was successfully validated against CRM DORM-2 (dogfish muscle). Quantitative As recovery in CRM (DORM-2) was obtained and no statistical differences were found at 95% level by applying the t-test. The limit of detection (LOD) and limit of quantitation (LOQ), for As were established as 0.022 and 0.063 μg g−1, respectively. The results of this study indicated that As concentration in fish tissues from the Indus River are generally lower than in tissues of fishes from Manchar Lake. Arsenic concentrations in fish tissues of Indus River are although above the respective human health-based concentrations.
Non-chromatographic speciation of toxic arsenic in fish
Talanta, 2005
A rapid, sensitive and economic method has been developed for the direct determination of toxic species of arsenic present in fish and mussel samples. As(III), As(V), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) were determined by hydride generation-atomic fluorescence spectrometry using a series of proportional equations without the need of a chromatographic previous separation. The method is based on the extraction of arsenic species from fish through sonication with HNO 3 3 mol l −1 and 0.1% (m/v) Triton and washing of the solid phase with 0.1% (m/v) EDTA, followed by direct measurement of the corresponding hydrides in four different experimental conditions. The limit of detection of the method was 0.62 ng g −1 for As(III), 2.1 ng g −1 for As(V), 1.8 ng g −1 for MMA and 5.4 ng g −1 for DMA, in all cases expressed in terms of sample dry weight. The mean relative standard deviation values (R.S.D.) in actual sample analysis were: 6.8% for As(III), 10.3% for As(V), 8.5% for MMA and 7.4% for DMA at concentration levels from 0.08 mg kg −1 As(III) to 1.3 mg kg −1 DMA. Recovery studies provided percentages greater than 93% for all species in spiked samples. The analysis of SRM DORM-2 and CRM 627 certified materials evidenced that the method is suitable for the accurate determination of arsenic species in fish.
Analytical and Bioanalytical Chemistry, 2005
An analytical method for the determination of inorganic arsenic in fish samples using HPLC-ICP-MS has been developed. The fresh homogenised sample was subjected to microwave-assisted dissolution by sodium hydroxide in ethanol, which dissolved the sample and quantitatively oxidised arsenite (As(III)) to arsenate (As(V)). This allowed for the determination of inorganic arsenic as a single species, i.e. As(V), by anion-exchange HPLC-ICP-MS. The completeness of the oxidation was verified by recovery of As(V) which was added to the samples as As(III) prior to the dissolution procedure. The full recovery of As(V) at 104±7% (n=5) indicated good analytical accuracy. The uncertified inorganic arsenic content in the certified reference material TORT-2 was 0.186±0.014 ng g À1 (n=6). The method was employed for the determination of total arsenic and inorganic arsenic in 60 fish samples including salmon from fresh and saline waters and in plaice. The majority of the results for inorganic arsenic were lower than the LOD of 3 ng g À1 , which corresponded to less than one per thousand of the total arsenic content in the fish samples. For mackerel, however, the recovery of As(III) was incomplete and the method was not suited for this fatrich fish.
Sains Malaysiana
ABSTrACT Fish is one of the most important sources of arsenic exposure in human diet and the Food Safety and Quality Division, Ministry of Health since 2007 has required routine monitoring of total arsenic in seafoods such as fish. This study describes an improved extraction method of total arsenic in fish using microwave assisted acid digestion procedure before being analysed by inductively coupled plasma mass spectrometry (ICP-MS). The parameters studied were pre-treatment of sample, digestion temperature, time programme and the chemicals (HNO 3 /H 2 O 2) used. Arsenic contents in fish samples under these conditions were compared using the standards additions technique. Microwave assisted acid digestion method with a combination of ultrapure concentrated nitric acid (HNO 3) to concentrated hydrogen peroxide (H 2 O 2) at a ratio of 7 mL: 1 mL, run time of 25 min and digestion temperature of 200°C with no pre-treatment was found to have recovery of 100.7% as compared with other dige...
2015
Direct solid sample analysis with graphite furnace atomic absorption spectrometry (SS-GF AAS) was investigated initially with the intention of developing a method for the determination of total As in fish and other seafood. A mixture of 0.1% Pd þ0.06% Mg þ 0.06% Triton X-100 was used as the chemical modifier, added in solution over the solid samples, making possible the use of pyrolysis and atomization temperatures of 1200 1C and 2400 1C, respectively. The sample mass had to be limited to 0.25 mg, as the integrated absorbance did not increase further with increasing sample mass. Nevertheless, the recovery of As from several certified reference materials was of the order of 50% lower than the certified value. Strong molecular absorption due to the phosphorus monoxide molecule (PO) was observed with highresolution continuum source AAS (HR CS AAS), which, however, did not cause any spectral interference. A microwave-assisted digestion with HNO 3 /H 2 O 2 was also investigated to solve the problem; however, the results obtained for several certified reference materials were statistically not different from those found with direct SS-GF AAS. Accurate values were obtained using inductively coupled plasma mass spectrometry (ICP-MS) to analyze the digested samples, which suggested that organic As compounds are responsible for the low recoveries. HPLC-ICP-MS was used to determine the arsenobetaine (AB) concentration. Accurate results that were not different from the certified values were obtained when the AB concentration was added to the As concentration found by SS-GF AAS for most certified reference materials (CRM) and samples, suggesting that SS-GF AAS could be used as a fast screening procedure for inorganic As determination in fish and seafood.