Determination of tin in canned foods by X-ray fluorescence spectrometry

Abstract

Wavelength-dispersive X-ray fluorescence spectrometry following a simple pretreatment was developed to determine levels of dissolved tin in canned foods. Sample syrup or a homogenate solution of fruit (meat) was freeze-dried and diluted with the same weight of cellulose powder. The mixed powder was then quickly formed into a pellet for X-ray measurements. This analytical method (detection limit, 5 ppm) was used to determine levels of tin in several kinds of canned foods from the present markets. The analytical results indicated that high concentrations (100-300 ppm) of tin were present in cans of many kinds of fruit, and a relationship was observed between the concentration and the length of time after manufacture. After a can was opened, the amount of dissolved tin rapidly increased. These results are consistent with those of Horio et al., which suggests that the issue of tin dissolving from cans has not been adequately addressed, despite their previous warning.