Coumarin 153, a solvatochromic fluorescent probe, for analyzing the biodiesel blends derived from various feedstocks

Biodiesel is renewable energy source an alternative to conventional fossil fuels. The primary concern lies in detecting alcohol content in biodiesel, which can either be intentionally added by adulterants or remain in trace amounts from the refining process of biodiesel synthesis. In order to regulate the quality of biodiesel production, it is crucial to develop an analytical method for monitoring alcohol content in biodiesel. Present study identified Coumarin 153 (C-153) with outstanding solvatochromic characteristics in multiple biodiesel feedstocks (soybean, canola, sesame, and corn). Based on our spectroscopic investigations, this alcohol (methanol, ethanol, and propanol) sensing method has proven to be rapid, sensitive, ratiometric, and visually discernible, and the detection limit for ethanol in soybean biodiesel could reach 0.23 % v/v. The percentage of alcohol (0-100 % v/v) in the biodiesel determines significant changes in the lifetime values of the C-153 from 5.1 ns to 0.35 ns. Moreover, we depict explicit solvation models (ethanol) and implicit solvation models (biodiesel) from quantum chemical calculations to explain the experimental results. Based on our study, C-153 with alcohol sensing capabilities seems to have potential applications in biodiesel analysis. The present results will inspire future efforts to simplify and optimize the detection of alcohol in biodiesel by using optical methods.