P-60. Correlation of automated Total SO2 DTNB method to EBC/ASBC para-rosaniline methods

Presenter: Mari Klemm, Thermo Fisher Scientific, Vantaa, Finland
Coauthors: Paula Ranta, Liisa Otama, and Annu Suoniemi- Kähärä, Thermo Fisher Scientific, Vantaa, Finland

Sulfur dioxide (SO2) in beer primarily originates from yeast metabolism. SO2 reacts with carbonyl compounds to form hydroxysulfonates, which increase the flavor threshold of carbonyl compounds responsible for stale flavor. SO2 also has an important role as an antioxidant and is known to exert antimicrobial properties at high concentrations. SO2 level is controlled at the end of beer production due to human health and beer quality reasons. Total SO2 in beer typically is measured using EBC Method 9.25.3 or the similar ASBC Beer-21 p-rosaniline method. This paper shows the correlation of beer samples measured using the p-rosaniline method to the total SO2 method, which is based on DTNB (5,5'-dinitrobenzoic acid) measurement at 405 nm. In this study, commercial beer samples and cider samples were analyzed using a Thermo Scientific Gallery discrete photometric analyzer. This rapid 2-reagent Gallery system method was performed without any sample pretreatment before the analysis. A fully automated bench-top photometric analyzer concept enables simultaneous analysis of multiple parameters, like color, from the same sample. According to this study, all samples tested using the total SO2 method with Gallery system showed result levels similar to the EBC (9.25.3) and ASBC Beer-21 p-rosaniline methods. The easy-to-use Gallery system method is a robust method for total SO2 measurement for both cider and beer samples. Ready-to-use Thermo Scientific liquid reagents eliminate reagent preparation, saving time in testing, and the volume-optimized system kits minimize reagent waste. The method is linear from 2–50 mg/L, and using automated dilution total SO2 can be measured up to 300 mg/L.

Mari Klemm received an M.S. degree in analytical chemistry from the University of Helsinki in 2008. She joined Thermo Fisher Scientific in 2008 in their Research and Development Department, where she worked as an R&D scientist. Mari is a member of the R&D team responsible for development of important beer analyzing applications, like beta-glucan and NOPA, as well other food and environmental chemistry tests for discrete analyzers. She specializes in SO2 analytics, starting in 2007 with automating wine SO2 analysis. Since January 2013 she has functioned as the technology manager responsible for new industrial applications.

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