Chemical Speciation of Arsenic and Chromium in

Overview

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Key numbers

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• (EDTA) at 90 °C for 40 min. Recoveries from 88 to 106% of arsenobetaine (AsB), arsenite (As(III)),
• is the most suitable combination for the speciation of As and Cr.6,14,25 This coupling enables excellent and
• MS. It was fitted with a reaction and collision cell pressurized with high purity He (99.9999%) (White
• determination, respectively. High-purity argon(99.999%) (White Martins-Praxair) was used for plasma
• Mobile phase 0.01 mol L-1 (NH4)2HPO4 + 1% (v v-1) CH3OH pH 8.0
• All glass and plasticware were kept in 10% HNO3 (v/v) for at least 24 h and washed with water before
• (30% wt., Sigma-Aldrich, Saint Louis, MO, USA) were used for sample preparation procedures.
• 1% (v v-1) HNO3 from a standard solution for ICP-MS (Fluka, Buchs St. Gallen, Switzerland). Internal
• standard (IS) solution of 500 μg L-1 Ga was prepared in 1% (v/v) HNO3 from a 1000 mg L-1 Ga IS solution
• daily by dissolving the salt (NH4)2HPO4in water containing 1% (v v-1) CH3OH (methanol HPLC grade,
• Recoveries from 87 to 99% were obtained by the proposed method and reference values of the certified
• reference materials (Table SI, Supplementary Material). No significant differences (t-test at 95%) were
• (NH4)2HPO4 in 1% (v/v) CH3OH (pH 8.0) as mobile phase.
• The solution 0.01 mol L-1 (NH4)2HPO4 in 1% (v/v) CH3OH (pH 8.0) was selected as the mobile phase.
• extractor solution were adapted according to extraction procedures described in the literature.11,14 Table II
• generated from the seafood analysis. A correlation coefficient greater than 0.97 (95% of confidence level)
• Expa Temperature (ºC) Time (min) Mass (g) (EDTA) (mol L-1) CR (%)b
• Expa Temperature (ºC) Time (min) Mass (g) (EDTA) (mol L-1) CR (%)b
• levels. The estimated correlation coefficient was 0.94 (95% of confidence level). Therefore, this indicates a
• For chromium, the LOQs were 114 ng g-1 (Cr(III)) and 54 ng g-1 (Cr(VI)).
• initially ≤ LOQ, we added about 3 times the LOQ of the respective specie to the final solution (considering
• between 70 and 120% are described as satisfactory in speciation analysis.35
• with the certified value of total certified As with a confidence level of 95% (Table IV). Chemical speciation in
• (100 mg of sample, 0.03 mol L-1 HNO3 as extracting solution, and 0.01 mol L-1 (NH4)2HPO4 in 1% CH3OH
• (pH 8.0) as mobile phase). The obtained results are presented in Table IV, and the chromatograms are in
• with the values obtained by the digestion method for all seafood samples with a confidence level of 95%.
• Table IV. Total As and As species in CRM, RM, and seafood, using the proposed method (mean ± standard deviation, mg kg-1, n=3)
• corresponding to about 3 times the LOQ of the respective species was added to the determination solution
• Supplementary Material), and deemed quantitative to all samples. In speciation analysis, 70 to 120%
• certified Cr(VI) value, with a recovery of 97% (at 95% of confidence level).
• mol L-1 EDTA + 0.005 mol L-1 NaH2PO4 (pH 7.0) as mobile phase. The results are presented in Table V,
• contaminated soil with Cr(VI) presented recovery of 97%.
• Table SII. Recovery tests of As species (n = 3) in fish samples
• Table SIII. Recovery tests of Cr species (n = 3) in fish samples and CRM

Methods (brief)

• seafood, exploring the LC-ICP-MS potential and
• data by LC-ICP-MS were obtained with 0.01 mol
• sample and 30 mmol L-1 HNO3 at 90 °C for 45
• min, and Cr, 0.1 g of sample and 0.045 mol L-1
• dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), arsenate (As(V)), Cr(III) and Cr(VI) were
• obtained for all evaluated samples. The limits of quantification provided by the proposed methods were
• 5.3; 52.1; 16.4; 2.8; 83.3; 113.8; 53.9 ng g-1 for AsB, As(III), DMA, MMA, As(V), Cr(III) and Cr(VI) respectively.
• Keywords: LC-ICP-MS, seafood, chemical speciation analysis, Doehlert, Box-Behnken, sample
• Cite: de Sá, I. P.; da Silva, C. A.; Nogueira, A. R. A. Chemical Speciation of Arsenic and Chromium in Seafood by LC-ICP-MS.
• (MMA) and dimethyarsenic acid (DMA).3,4 Moreover, arsenobetaine (AsB), arsenocholine (AsC), and other
• Different methods have been proposed for sample preparation for As speciation in fish, the most
• can affect sample integrity if the parameters are not well adjusted.23 On the other hand, microwave
• extraction methods with HNO3 reduce sample preparation time and, consequently, the risk of species
• Several methods for extracting chromium species from food samples were found in the literature,
• however nonspecific to fish samples.18 Alkaline salts are generally used to extract Cr(VI) in food samples.
• Hyphenated liquid chromatography with inductively coupled plasma mass spectrometry (LC-ICP-MS)
• Considering the discussion, LC-ICP-MS procedures for As and Cr speciation were explored to establish
• to optimize the extraction conditions of the As(V), As(III), AsB, MMA, DMA, Cr(III), and Cr(VI) species in

Implications

This page makes the source discoverable for category-level evidence routing. Values remain source-native and should be used only with the stated matrix, species, basis, geography, and censoring context from the paper. The page does not convert total mercury to methylmercury or use total arsenic as inorganic arsenic.

Wiki pages this source may touch

• Fish — marine, non-predatory (sardines, anchovies, salmon, cod)
• Shellfish (shrimp, crab, lobster, clams, oysters, mussels)
• Mercury
• Arsenic
• Chromium

Verification notes

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