The Determination of Trace Amounts of Tin by Inductively Coupled Argon Plasma Atomic Emission Spectrometry with Volatile Hydride Method

A sensitive method is described for the determination of trace amounts of tin, based on continuous sodium borohydride reduction of tin in solution to gaseous stannane. The stannane generated is introduced into a relatively low-powered (1.6 kW) inductively coupled argon plasma source. The effects of a range of acids and interelement effects are investigated. Mixtures of nitric and succinic acids and of nitric and malic acids are the most suitable reaction media, especially in the presence of interferents. The method of standard additions is recommended for accurate tin determination. Compared to a conventional solution nebulization, the present system gives a sensitivity increase of a factor of approximately 3 orders of magnitude. The detection limit for tin is 0.05 ng/ml and precision values at 20 and 50 ng/ml Sn are less than 3% relative standard deviation. The linear calibration range spans nearly 5 orders of magnitude. The proposed method is applied to the determination of tin in low alloyed steels and in National Bureau of Standards standard reference materials (Cu-Ni alloy, orchard leaves, wheat flour, and rice flour).