A portable colorimetric array reader for toxic gas detection

Smartphones have been rapidly expanding with their various applications. In this study, we have developed a portable array reader to interact with smartphones. This array reader can detect the color changes of the colorimetric strip responding to various hazardous gases through the complementary metal oxide (CMOS) image sensor. The array strips responding to toxic gases consist of dyes that change color based on the acid-base reaction. Therefore, the dye color changes according to the acidity, and the array reader monitors the color change in real time to create chrominance data. In this experiment, the array reader was evaluated by detection of ammonia, methylamine, and trimethylamine (TMA). The data of the detected gas transferred to the smartphone that display the type and concentration of the harmful gas on the screen. This study proved that this array reader is a possible system for real-time detection of harmful gases, biomolecules, and chemicals through the colorimetric methods.