Self-assembled monolayer of copper(II) meso-tetra(4-sulfanatophenyl) porphyrin as an optical gas sensor

This paper reports the use of an optical sensing technique to develop a receptor for organic gases by using the assembled monolayer of Cu(II) meso-tetra(4-sulfanatophenyl) porphyrin (CuMTSP). The monolayer was deposited on a quartz substrate by immersing the substrate into its aqueous solution for 30 min at 5 °C. The thin film was used to detect the saturated vapor of ethanol, 2-propanol and cyclohexane in airflow of 15 l/min. The sensing sensitivity was based on the changes in optical absorption at 514 nm of the self-assembled monolayer (SAM) upon exposure to gas samples. It was found that the thin film exhibited a good sensitivity and reproducibility towards all vapor samples.