Preliminary Investigations of Correlations Between Total Mercury in Tuna and Quality Control, and Mercury Recoveries Using Microwave Digestion

ABSTRACT

Mercury levels in commercially available tuna are of particular concern, as mercury found in tuna exists mostly as highly toxic methylmercury compounds that are readily absorbed by the gastrointestinal tract in humans. For five brands of canned tuna purchased locally and analyzed in quadruplicate for Hg via microwave digestion and cold vapor atomic absorption spectrometry (CVAAS), Hg levels ranged from 0.19-(±0.07)-µg Hg/g to 3.60-(±0.17)-µg Hg/g. Statistical analysis of the results suggested that three of the brands of tuna studied were statistically comparable and that two of the brands were significantly different, at the 95% confidence interval. Mercury recoveries for external calibration standards and known amounts of mercury added to tuna samples indicated minimal or no loss of Hg during microwave digestion.

KEYWORDS:

• calibration
• cold vapor atomic absorption spectrometry (CVAAS)
• mercury
• microwave digestion
• recovery
• sample inhomogeneity
• tuna

ACKNOWLEDGMENTS

The authors are grateful for the financial support of the Society for Analytical Chemists of Pittsburgh (SACP), the Spectroscopy Society of Pittsburgh (SSP), Air Quality Services (Pittsburgh, PA); the continued support of the campus administration and the Division of Natural Sciences, Mathematics, and Engineering at Pitt-Greensburg; and Theresa Stauffer's critical review and editorial contributions during preparation of this manuscript.

Notes

^a Four replicate determinations were performed for each brand of tuna.