Routine, High-Sensitivity, Cold Vapor Atomic Absorption Spectrometric Determination of Total Mercury in Foods after Low-Temperature Digestion

Abstract

A cold vapor atomic absorption spectrometric method was developed for the subnanogram-per-gram determination of total Hg in a wide variety of foods. Foods were weighed into 50 mL polypropylene centrifuge tubes and dried without charring at 55°C in a circulating oven. Samples were then digested at 58°C with HNO3, HCl, and H2O2. After matrix modification with solutions of 2% Mg(NO3)2, 0.01% Triton X-100, and Cu(II) at 10 μg/mL, samples were analyzed by using a CeTAC Technologies M-6000A dedicated Hg analyzer. Based on a 2 g sample weight, the detection limit of the method over 12 batches averaged 0.30 ng/g wet weight and ranged from 0.03 to 0.6 ng/g. Recoveries of Hg added to 17 different foods, analyzed in a routine manner, averaged 97%, and individual recoveries ranged from 77 to 107%. Accuracy was confirmed by analysis of 7 biological reference materials from the National Research Council of Canada and the National Institute of Standards and Technology. Stabilization of low concentrations of Hg in solutions containing no sample was required to prevent loss of Hg from blanks. In a comparison of NaCl, potassium dichromate, and Au(III), chloride was much more effective for stabilization than the other two, and HCl was used for subsequent stabilization.

Levels of total mercury in predatory fish sold in Canada in 2005

“…Analyses were performed using the reagents, instrumentation and methodology described in Dabeka et al (2002) . Briefly, after a low-temperature nitric/hydrochloric acid and hydrogen peroxide digestion of roughly 1 g fish tissue and dilution to 50 ml with water, measurements were made using a CETAC-6000A dedicated Hg analyser equipped with an ASX-500 autosampler and ADX autodilutor.…”

Design and characterisation of a vapour generation system for determination of mercury by atomic absorption spectrometry

“…The combined effect of the two trends on the signal to background ratio as a plot of the ratio (DS/DB) and (1/F total ), 4 shows a very high correlation (r ¼ 0.9996), where DS and DB are the changes in the signal and background, respectively.…”

“…Mercury and its organic compounds are well known neurotoxins, even at very low concentrations, and sensitive techniques such as cold vapour atomic absorption spectrometry (CV-AAS) [1][2][3][4][5][6][7][8][9] have been developed to measure low concentrations. The CV approach separates the analyte from the sample matrix and transports it to the atom cell with nearly 100% efficiency.…”

Atomic spectrometry update. Clinical and biological materials, foods and beverages

“…223,224 Optimised digestion procedures for specific applications seen include those for measuring Se in yeast 226 and Hg in various foods. 227 A rapid automated digestion apparatus was developed by Jacob and Berndt 9 with direct coupling for FAAS. Powdered samples suspended in 2.5 M HNO 3 passed through a Pt-Ir capillary heated electrically to 320 uC and the analysis was completed within 3 min.…”