Simple and ultrasensitive microplate method for spectrofluorimetric determination of trace resorcinol

• A new spectrofluorimetric method for the determination of resorcinol is presented.
• The method uses coumarin formation with methylacetoacetate.
• It is highly selective and specific for resorcinol.
• The method was validated on real samples (wastewater, cosmetics)

In this paper, a new spectrofluorimetric method is proposed for the fast, simple, and accurate determination of trace resorcinol in the microplate format (high-throughput screening). The analytical method is based on the formation of a coumarin derivative with methyl acetoacetate via a Pechmann condensation reaction. Experimental conditions have been optimized, and excellent analytical performances have been achieved with a limit of detection of 0.46 μg L− 1, a wide linear range between 1.5 and 1000 μg L− 1 and a relative standard deviation of 2.01% (n = 10).This method is remarkably specific for resorcinol compared to other phenols and hydroxyphenols and suffers from low interferences from other potential matrix components. The proposed protocol was finally applied and validated on real samples such as wastewater or pharmaceutical/cosmetic samples.