Concentration of inorganic arsenic in samples of white rice from the United States

Concentrations of inorganic arsenic were determined by ion-trap, electrospray, mass spectrometry in 40 samples of white rice, which were collected in the United States. Inorganic arsenic was qualitatively present in all samples. The quantitative range of concentrations of inorganic arsenic extended from <0.025 to 0.271 μg/g (wet-mass basis). The extremes of the range were validated with acceptable analytical recoveries of fortifications. Statistical bounds of the range were established and assessed. The distribution of concentrations over the observed range was characterized statistically with an empirical lognormal probability distribution function. For the samples of white rice, a geometric mean corresponding to 0.112 μg/g and a geometric standard deviation equivalent to 0.055 μg/g of inorganic arsenic were derived from the empirical lognormal function.