A supersensitive fluorescent probe for biothiols by regulating the click reaction and its application in glutathione detection in food samples

Abstract

A new fluorescent molecular probe (NAM2) with extending conjugation system between the recognition group and naphthalimide fluorophore group was developed for selective and sensitive detection of biothiols. The conjugation system of a phenyl ring with the naphthalimide group improved the efficiency of photoinduced electron transfer (PET). The molecular probe showed a supersensitive “off-on’’ response to glutathione (GSH) and homocysteine (Hcy), and it allowed detecting GSH and Hcy linearly in a range of 0–3 μM with detection limits of 0.0011 μM and 0.0032 μM, respectively. Significantly, the new sensor was applied in accurate detection of GSH in vegetables and fruits with recoveries of 87.26–96.72% (RSDs<3.5%, n = 3), and it was validated by a phthalaldehyde-derivatisation method. The fluorescence spectrometry based on the sensor NAM2 is a high-quality and promising analytical tool for GSH analysis in food samples.