Rapid and quantitative release, separation and determination of inorganic arsenic [As(III)+As(V)] in seafood products by microwave-assisted distillation and hydride generation atomic absorption spectrometry

Overview

Munoz and colleagues developed and validated a microwave-assisted distillation method for measuring inorganic arsenic, defined as As(III)+As(V), in seafood products by hydride generation atomic absorption spectrometry. The paper includes occurrence values for 21 natural seafood samples, reporting total arsenic and inorganic arsenic on a dry-mass basis. The table is useful because it keeps total arsenic and inorganic arsenic separate in fish, shellfish, fresh, canned, and frozen seafood matrices.

Key numbers

The abstract reports a method detection limit of 10 ng g−1 (dry mass) or 2 ng g−1 (fresh mass), precision 4% RSD, recoveries 106±3% for As(III) and 113±4% for As(V), and an estimated mean overestimate of inorganic arsenic of about 24 ng g−1 dry mass (dm) from co-distilled minor species. The natural seafood samples had inorganic arsenic by the proposed method ranging from 0.053 to 1.145 µg g−1 (dm), with mean moisture content 78%.

Table 5 reports total arsenic and inorganic arsenic in µg g−1 (dm). Total arsenic was determined in duplicate, and inorganic arsenic was determined in triplicate.

The paired-method comparison found no significant difference between inorganic arsenic values from microwave distillation and solvent extraction, with P-value 0.66 at a 95% confidence level. The paper reports that inorganic arsenic percentages in the seafood samples varied from 0.5-12.6%, with mean 3.9±3.3%.

Reference-material checks reported total arsenic found/certified values in µg g−1 (dm) of DORM-1 16.2±0.4/17.7±2.1, DORM-2 17.9±0.5/18.0±1.1, and TORT-2 22.3±0.2/21.6±1.8. For the proposed inorganic-arsenic method, Table 4 reports As(III)+As(V)+MMA+11% DMA values of DORM-1 0.196±0.004 µg g−1 (dm), DORM-2 0.102±0.029 µg g−1 (dm), and TORT-2 0.506±0.031 µg g−1 (dm).

Methods (brief)

Fresh, frozen, and canned seafood products were purchased at local retail outlets; canned brine or sauce was removed, samples were cut, frozen at −20 °C, freeze-dried for 48 h, homogenized, and stored at 4 °C. Inorganic arsenic was measured by microwave-assisted distillation followed by HGAAS in continuous-flow mode using a Perkin-Elmer Model 5000 atomic absorption spectrometer with a Perkin-Elmer FIAS 400 hydride-generation system. The proposed method weighed 0.50±0.01 g lyophilized sample, used KI plus ascorbic acid and 8.25 mol l−1 HCl, and completed distillation in 4-6 min at maximum 700 W microwave power. Total arsenic was measured by dry-ashing HGAAS. The method targets As(III)+As(V) but the authors report a small mean overestimate from co-distillation of MMA and DMA; no other HMI metals were measured.

Implications

This source supplies direct seafood inorganic-arsenic occurrence evidence with total arsenic side by side for the same samples. It can support fish, shellfish, seafood, and canned-seafood pages where dry-mass inorganic arsenic (iAs) and total arsenic (tAs) values are needed, while keeping the paper’s dry-mass basis separate from fresh/as-consumed bases until a later normalization pass. The sample types are broad product forms rather than brands, so the values should route by seafood category and product form, not by named retail product.

Update history

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