Pervaporation-flow injection method for the determination of sulfur dioxide in food and air samples
2011
Balansay, L.S. | de Leon, L.G. | Quiret, L.L. | del Mundo, F.R.
A pervaporation-flow injection method was developed for the analysis of sulfur dioxide (SOsub2) in food and air samples. The method is based on the spectrophotometric measurement of the decrease in absorbance of malachite green (MG) solution at 617 nm due to pervaporated and subsequent dissolution of SOsub2. The optimized system variables were MG concentration (2.4 x 10 sup-5 M, buffered at pH 5.64 or 5.82), H2SO4 (0.20 M), donor stream flow rate (0.60 mL/min), acceptor stream flow rate (0.60 mL/min), reaction coil length from injector to donor chamber inlet (50.0 cm), reaction coil length from acceptor chamber outlet to flow cell (50.0 cm), and injection volume (60 uL). The optimized system has a linear working concentration range of 1-5 ug/mL SO2 and the calculated limit of detection was 0.33 +- 0.02 ug/mL SO2 (7.6% RSD, n=4). The method was satisfactorily applied to the determination of SO2 content of some wines, vinegar, beverage, and ambient air samples.
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