Sensitive and selective colorimetric sensing of acetone based on gold nanoparticles capped with l-cysteine

Au nanoparticles (AuNPs) are increasingly utilized as sensitive (bio) chemical probes due to their exceptional physicochemical properties and ease of functionalization. AuNPs, when functionalized with proper ligands, allow the development of highly selective colorimetric sensor. The aim of this paper was to discuss the usage of a reliable and sensitive colorimetric sensor, for sensing dissolved acetone based on the l-cysteine capped gold nanoparticles. The AuNPs were modified with l-cysteine through Au–S bonds. Acetone adsorbs on the surface of l-cysteine-AuNPs and induces the aggregation of AuNPs, due to the strong hydrogen-bonds formed between cysteine and acetone. Upon the addition of Acetone, the solution showed a color change from red to blue, which was also monitored by visible spectra. Under optimum conditions, acetone was detected at concentrations higher than 6.5 × 10−7 mol L−1, with a linear range from 1.0 × 10−6 to 6.1 × 10−5 mol L−1. The relative standard deviation for six replicates determinations of 2.0 × 10−5 mol L−1 of acetone was calculated to be 1.2 %.The selectivity was investigated by assaying some potentially interfering chemicals.