A Sulfur Dioxide Concentration Detector for Daylily Food Safety Applications

In this work, a sulfur dioxide concentration detector is newly proposed for daylily food safety applications. The proposed detector consists of a sulfur dioxide sensor and a converter. The proposed detector can linearly convert sulfur dioxide concentration in daylily solution into output time period. By the output, sulfur dioxide concentration in daylily solution could be gotten quickly and conveniently. Furthermore, in order to be suitably used in different sulfur dioxide concentrations, the proposed converter with low range of sensing resistance was designed. The measured sensing resistance was from 0.1 to 100
$\text{k}\Omega $
, and the output time period was corresponding from
$33.1 ~\mu \text{s}$
to 33.12 ms. The sensitivity was
$331.2 ~\mu \text{s}/\text{k}\Omega $
. The measured range of sulfur dioxide concentration in daylily solution was 200–1600 ppm, and the output time period was 1.17 ms–
$472 ~\mu \text{s}$
. The measured maximum linear error of 0.347% was obtained. Finally, two different sulfur dioxide concentrations in daylily solutions were experimented. By measured and experimented results, the proposed sulfur dioxide concentration detector was functioning normally for daylily food safety applications.