[Determination of trace tin in food by solid-phase spectrophotometry]

A new method for the determination of trace amounts of tin by resin-phase spectrophotometry has been developed and the detailed experimental conditions investigated. Tin ion reacts with procatechol violet(PV) in potassium hydrogen phthalate-HCl buffer media(pH2.5) to form a stable complex. The complex enriched on an anion-exchange resin has a maximum absorption wavelength of 570 nm. The absorbance is directly proportional to the concentration of tin in the region of 0-150 micrograms.L-1 with an apparent molar absorptivity of 7.2 x 10(6) L.moL-1.cm-1. Most of the co-existed metal ions do not interfere the determination of tin ion. The developed procedure has been successfully employed to the determination of tin in some food examples.