Application Description

GB5009.34-2022 "Determination of Sulfur Dioxide in Food"; 2015 & 2020 editions of "Chinese Pharmacopoeia" for testing sulfur dioxide residues in TCM materials and decoction pieces

GB5009.34 and the 2015 "Chinese Pharmacopoeia" specify three sulfur dioxide detection methods: acid-base titration, spectrophotometry (food)/gas chromatography (TCM), and ion chromatography. Spectrophotometry/gas chromatography and ion chromatography offer high sensitivity and strong specificity but require expensive instruments, hindering grassroots adoption.

Acid-base titration is simple and low-cost, making it the statutory method in food national standards and pharmacopoeia. However, existing setups require continuous improvement in procurement, configuration, and implementation. For example: (1) Beyond glassware, magnetic stirrers, electric heating sleeves, titration platforms, and nitrogen flow meters are needed, complicating assembly. Many institutions find the process cumbersome and abandon the method; (2) Assembled setups face issues like unstable nitrogen flow, uneven heating, leaks, boiling over, and cooling water interference, leading to poor parallelism and low recovery rates; (3) Low efficiency—current single-unit setups struggle with batch processing, increasing time and labor costs for multi-sample TCM testing.