Analytical procedure for total mercury determination in fishes and shrimps by chronopotentiometric stripping analysis at gold film electrodes after microwave digestion

• Published in: Food chemistry Vol. 101; no. 2; pp. 579 - 584
• Main Authors: Augelli, M.A., Munoz, R.A.A., Richter, E.M., Cantagallo, M.I., Angnes, L.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2007
• Subjects: Chronopotentiometric stripping analysis; contaminants; electrodes; Fish; food contamination; freshwater; gold; Gold electrodes; hydrogen peroxide; Mercury; Microwave digestion; microwave treatment; nitric oxide; Pisces; potentiometers; seafoods; Shrimp; Brazil; Brazil, Sao Paulo; Fish; Microwave digestion; Mercury; Gold electrodes; Shrimp; Chronopotentiometric stripping analysis
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2006.02.017

A method for the total mercury determination in fish and shrimps employing chronopotentiometric stripping analysis on gold film electrodes is described. Fish and shrimp tissues were digested using a microwave oven equipped with closed vessels. We developed a microwave heating program which decomposed all the samples employing diluted nitric acid and hydrogen peroxide. The proposed method was validated by analyzing a certified reference material and then applied for different fish species from fresh water and seawater acquired in local markets of São Paulo city, Brazil. The Brazilian legislation establishes 0.5 and 1
mg per kilogram of fish as upper limit of mercury for omnivorous and predator species, respectively. Except for blue shark tissues, the mercury content was situated below 0.5
μg g
−1 for all the analyzed samples. The detection limit of the proposed method was calculated as 5
ng g
−1 of sample utilizing 5 minutes of electrodeposition (+300
mV vs. Ag/AgCl) on the gold electrode.