Turn-off fluorescent magnetic Mn-ZnS molecularly imprinted probe for the detection of chlorpyrifos in vegetable samples

A sensitive and efficient fluorescent sensor based on a magnetic manganese-doped zinc sulfide molecularly imprinted probe (Fe₃O₄/Mn-ZnS/MIP) was successfully developed for the detection of chlorpyrifos (CPF). The probe combined the advantages of magnetic separation, the fluorescence properties of Mn-ZnS, and the exceptional molecule recognition capabilities of molecularly imprinted polymers. The developed sensor exhibits selective binding to CPF, resulting in a quenching of fluorescence intensity of Fe₃O₄/Mn-ZnS/MIP by a photo-induced electron transfer mechanism. The sensor demonstrated a detection limit of 0.41 ng/mL within a linear range of 1-50 ng/mL. Further, the probe was effectively utilized to analyze vegetable samples (cabbage, and cauliflower), yielding recoveries of 97.10-102.15 %. The objective of this research is to contribute to the development of a highly effective fluorescence sensing system capable of detecting several dangerous substances, including chlorpyrifos.