An HBT-based "off-on" fluorescent probe for direct detection of methyl parathion in environmental water and Chinese medicine samples.

In this work, a simple and effective fluorescent probe (P1) was designed and synthesized using 2-(2'-hydroxyphenyl)benzothiazole (HBT) as the fluorescent core and an oxime group as the recognition site. The structure of P1 was well characterized and its direct detection performance for methyl parathion (MP) was investigated by fluorescence spectroscopy. The results showed that P1 displayed an "off-on" response to MP in aqueous solution with good selectivity and anti-interference ability, a wide linear range (0-40 µM), a low detection limit (1.69 µM) and a fast response time (<5 min). Besides, the practical detection of MP in environmental water and Chinese medicine (chrysanthemum) samples also showed good recoveries (93.5-101.2%) with relative standard deviations (RSD) less than 3%. Furthermore, P1-loaded test strips were manufactured and realized the visual detection of MP under 365 nm UV light.