J AOAC Int. 2002 Jan-Feb; 85(1): 31-5.

Determination of arsenic in homeopathic drugs by bromide volatilization-inductively coupled plasma-atomic emission spectrometry.

Lopez-Molinero A, Villareal A, Velilla C, AndÃa D, Castillo JR.

University of Zaragoza, Faculty of Science, Department of Analytical Chemistry, Spain. anlopez@posta.unizar.es

Arsenic in homeopathic drugs was determined by coupling a volatile generation with inductively coupled plasma-atomic emission spectrometry. The method is based on the chemical vaporization of arsenic(III) with bromide ions in sulfuric acid media using a batch procedure and subsequent introduction of the gaseous analyte into the plasma torch. The main and interactive effects of the experimental variables affecting this method were evaluated by a 2-level full factorial design. In optimized conditions by Simplex, the method shows an absolute detection limit (3 s) of 0.28 microg for the injection of 230 microL sample. The precision (% relative standard deviation) of the determination was 4.2% at a level of 50 microg/mL As(III) (n = 5). The interference effect of various ions on the arsenic signal was evaluated.