A new absorption based CO 2 sensor based on Schiff base doped ethyl cellulose

Abstract

This paper reports absorption-based CO2 sensing of the pH-active Schiff base 2-[(2-hydroxymethylphenylimino) methyl]-5-bromo-phenol (SB) in an ethyl cellulose (EC) matrix with and without Teflon coating. The CO 2 sensitivity of the SB dye in the EC matrix was evaluated in the presence of nonadecafluorodecanoic acid and tetrabutyl ammonium hydroxide. When exposed to CO 2 , the sensing films exhibited 76% of overall relative signal change and responded to CO 2 over a wide range: 1%-100 % (v/v). However, the slope of the spectral response between 1% and 5% (v/v) is more significant. The response time ( t90) was 15 s, and limit of detection (LOD) was 0.3% (v/v) CO 2 . The stability of SB in the EC matrix was excellent, and when stored in the ambient air of the laboratory there was no significant drift in signal intensity after 6 months. Our stability tests are still in progress. © TÜBITAK.