Development of a fast, simple, and sensitive colorimetric method to determine benzothiazole based on the plasmonic response of gold nanoparticles

In this article, for the first time, benzothiazole (BT) was determined using a simple, fast, and sensitive colorimetric method. This method was based on the surface plasmon resonance (SPR) property of gold nanoparticles (AuNPs) and interaction between BT and gold nanoparticles. The addition of BT leads to AuNPs aggregation with red-to-blue color shifts. TEM analysis demonstrated aggregation of gold nanoparticles at the presence of BT. The effective parameters in the SPR such as solution pH, concentration of AuNPs, standing time, electrolyte concentration, and coexisting substances were studied and optimized. Under the optimum conditions, this method exhibited a linear range from 10 to 200 ng mL(-1) (R-2 = 0.996), with a detection limit of 1 ng mL(-1). Relative standard deviations (RSD) for 40.0 and 140.0 ng mL(-1) of BT were 2.5 and 1.5%, respectively. Possible mechanism for the SPR changes of AuNPs in the presence of BT was discussed. Moreover, the cost-effective colorimetric method has successfully been applied for the analysis of various real samples.