Food Safety and Environmental Stewardship Program

Total antimony was determined by inductively coupled plasma atomic emission spectrometry (ICP AES) using hydride vapor generation. A1 g wet, 0.25 g dry, or 10 mL water sample was digested by one of 2 distinct methods in a 10 mL graduated Kimax culture tube on a programmed heating block by heating with nitric acid and then boiling in a mixture of sulfuric acid and perchloric acid. For soils, a 0.25 g sample was digested in a 10 mL volumetric culture tube with hydrochloric acid. After digestion, the samples were treated with hydrochloric acid and potassium iodide. The antimony was then reduced by sodium borohydride to stibine (SbH3) in a simplified, continuous-flow manifold. A standard pneumatic nebulizer effected the gas–liquid separation of SbH3, which was then quantified by ICP AES at 231.147 nm. The instrument detection limit was 0.41 μg/L. Recoveries from 10 matrixes were 80 to 100%, with a typical relative standard deviation of 5.3%. The digestion and analysis methods demonstrated statistical control for samples of environmental and biological interest and are especially well suited to analysis of small samples. This method requires no additional apparatus for hydride generation or sample introduction.