Determination of submicrogram amounts of arsenic and antimony by d.c. plasma arc emission spectrometry

The application of a d.c. plasma arc to the determination of submicrogram amounts of arsenic and antimony is described. Arsenic or antimony hydride generated by reduction with granulated zinc or zinc powder is collected in a liquid nitrogen trap and then swept into the plasma. The effects of the argon gas flow rates, d.c. are current, acid concentration, etc. were investigated. The limits of detection are 8 ng for arsenic and 40 ng for antimony. The standard deviations are 3.5% for 0.5 μg As and 4.5% for 0.6 μg Sb Interference from nitric acid up to 0.3—0.5 M could be removed by adding chromium(II) The proposed method was applied to the analysis of waste water and sea water.