There were many huge gas factory accidents. The one of reasons were leakage of toxic gases. The colorimetric sensors were one of the powerful toxic gases detecting method. Advantage of colorimetric sensors was unnecessary for special analyzing equipment. Only naked eyes were need. Most of acidic and basic gases were target gases for colorimetric sensors; HCl, HF, NH3 etc. pH-indicators as Bromophenol Blue(BPB), Bromocresol Green(BCG), Chlorophenol Red(CPR), and Bromocresol Purple(BCP) were used for dyes for colorimetric sensors . In this study, we made detecting kits for toxic gases by polymer matrix with pH-indicator dyes. Polymer matrix were Poly(vinyl butyral)(PVB) or Gelatin. pH-indicator dyes were usually used BPB and BCG. Additives were electron transfer agent(Hydroquinone(HQ)) and pH-adjuster(Polyvinylpyrrolidone(PVP)).The methods for making kits were electrospinning and lyophilization. The solvent for PVB using system was ethanol. So they were easy to electrospinning . But Gelatin using system's solvent was water, and water solution was hard to electrospinning. Electrospinning method made large surface area; Because of thin diameter. The lyophilization for gelatin made porous matrix. The porous matrix had large surface area too. The kits were exposed toxic gas by Mass flow controller (MFC). During exposing, we were recorded digital images to determine the color change. Colors were checked (L,a,b) coordination by software program. (L,a,b) coordination was absolute value of color. And the distance of (L,a,b) coordination from origin (delta E) can figure out how much change the color. So checking the delta E with time can how fast change the color. The variables were amounts of matrix and, ratio of dye to matrix/additive to matrix. Investigating sensitivity of color change and selectivity of toxic gases were key factor of this study. And the optimal ratio of dye/additive to matrix and also optimal amounts of matrix are summarized.
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