Development of a photometric procedure for tin determination in canned foods employing a multicommuted flow analysis approach

This work describes an automated analytical procedure for the photometric determination of tin in canned foods, employing a multicommuted flow analysis process. The flow system manifold comprised a set of three-way solenoid valves to handle solutions and a multisyringe module for fluid propelling. A PIC microcontroller, run using a software written in Visual Basic 6.0 language, was used to control the flow analysis setup and to perform data acquisition. Photometric detection was accomplished employing a homemade photometer, which consisted of an ultra-bright LED, a photodiode and a homemade flow cell with an optical path length of 200 mm. The procedure was based on the reaction of Sn( iv ) with pyrocatechol violet (PCV) in the presence of surfactants. After selecting the best operational conditions, profitable features such as, a linear response ranging from 0.10 to 1.25 mg L −1 , a limit of detection of 0.04 mg L −1 , a variation coefficient of 1.30% ( n = 10) and a sampling rate of 49 determinations per hour were achieved. By spiking samples with tin, recoveries between 95 and 110% were achieved. This work describes an automated analytical procedure for the photometric determination of tin in canned foods, employing a multicommuted flow analysis process. The flow system manifold comprises a set of three-way solenoid valves to handle solutions and a multisyringe module for fluid propelling.