Cobalt/Aluminum layered double hydroxide intercalated with rice straw based-biochar for recognizing organophosphates in cereal crops

Abstract

Herein, rice straw-based biochar was intercalated with Co/Al-LDH (LDH-Biochar) using a green technique based on the co-precipitation method. LDH-Biochar was further evaluated for the naked eye detection and spectrofluorimetric analysis of dibutyl phosphate (DBP), diphenyl phosphate (DPP), and diethyl chlorophosphate (DCP), which are extensively used as pesticides and flame retardants. The material inherited a fluorescent signal with a maximum at 570 nm (λ_exc = 520 nm) from the precursor ‘biochar’ and porous interactive surface from the precursor ‘LDH.’ It showed selective quenching for the organophosphates, i.e., DBP, DPP, and DCP, with a detection limit of 1.39 μM, 1.17 μM, and 1.29 μM, respectively, and the probe showed good response within the linear range of 1.9–25.3 μM. Furthermore, the method was successfully implemented to extract the organophosphates from wheat, corn, and pearl millet with recoveries in the range of 97.49–101.35 % (RSD; 0.27–3.22 %), 97.08–99.91 % (RSD; 0.27–3.17 %), and 98.18–103.54 % (RSD; 0.19–4.76 %), respectively. The outcome of this research is thus expected to help develop LDH-Biochar as a multi-analyte sensor for organophosphates (DBP, DPP, and DCP), which are extensively used as pesticides and flame retardants.