Atomic absorption spectrometric determination of copper in malt beverages

A rapid method is described for the direct determination of copper in malt beverages without preconcentration. A Zeeman background correction atomic absorption spectrometer was used with NH4H2PO4 as the matrix modifier. The samples containing alcohol ranging from 5-7% by volume were diluted fivefold with deionized water and analyzed directly. Calibration curves from aqueous standards were used to calculate the detection limit and to quantitate copper in the samples. The detection limit, calculated as 3 sigma/slope of the calibration curve, was 5 mu g/L in a malt beverage. The analytical results were verified by standard additions and spike recoveries. The recoveries ranged from 95-108% with relative standard deviations of <10%. A survey of several domestic and imported malt beverages revealed that the levels of copper in samples tested in this study were significantly less than the maximum tolerance level of 1000 mu g/L in bottled water and 1300 mu g/L in drinking water set by the United States Food and Drug Administration and the Environmental Protection Agency, respectively.