Enantioselective Analysis and Degradation Studies of Isocarbophos in Soils by Chiral Liquid Chromatography–Tandem Mass Spectrometry

Abstract

An enantioselective method is presented for the determination of isocarbophos in soil by liquid chromatography coupled with tandem mass spectrometry. The pesticide residues in soil samples were extracted with acetonitrile, and complete enantioseparation was obtained on an amylose tris(3,5-dimethylphenylcarbamate) chiral column using acetonitrile/2 mM ammonium acetate solution containing 0.1% formic acid (60:40, v/v) as the mobile phase. The absolute configuration of isocarbophos enantiomers was determined by the combination of experimental and calculated electronic circular dichroism spectra. The method was utilized to investigate the degradation of isocarbophos in soils (Changchun, Hangzhou, and Zhengzhou) under sterilized or native conditions. Isocarbophos enantiomers were configurationally stable in the selected soils, and the pesticide degradation was not enantioselective in the sterilized condition. The degradation behavior of rac-isocarbophos was different under native conditions, with no enantioselectivity in the Changchun soil and with the S-(+)-isocarbophos enriched in the Hangzhou and Zhengzhou soils.

Enantioselective determination of acaricide etoxazole in orange pulp, peel, and whole orange by chiral liquid chromatography with tandem mass spectrometry

“…The determination of the absolute configuration (AC) of chiral molecules is also an important aspect of chiral analysis . The rapid development of computerized time‐dependent density functional theory (TDDFT) has allowed the widespread application of chiroptical methods, such as vibrational circular dichroism and electronic circular dichroism (ECD), for the determination of the ACs of chiral molecules .…”

Simultaneous enantioselective determination of isocarbophos and its main metabolite isocarbophos oxon in rice, soil, and water by chiral liquid chromatography and tandem mass spectrometry

“…ICPO had already been metabolized from ICP after 6‐h soil incubation in this experiment. As is known from previous work , the AC of ( R )‐(−) and ( S )‐(+) would not be transformed into each other during the metabolization of ICP to ICPO. In other words, ( R )‐(−)‐ICP would metabolize to ( R )‐(−)‐ICPO and ( S )‐(+)‐ICP would metabolize to ( S )‐(+)‐ICPO.…”

“…According to previous studies , enantioselective chromatographic separation of ICP was performed on a Daicel Chiralpak AD‐RH column with a mobile phase of acetonitrile and 0.1% formic acid solution (60:40, v/v) and a column temperature of 30°C. In the present study concerning ICPO, four different chiral columns were selected to systematically explore the influence of the chiral stationary phase on the enantioseparation by HPLC–MS/MS.…”

“…Assignment of the AC is an important aspect for understanding the biochemical processing of chiral compounds .The AC of ICP enantiomers has been established by comparing the signs of the experimental ECD to that of the calculated spectra according to previous research . So the enantiomers were assigned as ( R )‐(−)‐ICP and ( S )‐(+)‐ICP in Fig.…”

“…As is well known, matrix interference usually makes identification by HPLC difficult, HPLC–MS/MS, which allows for a relatively simple sample preparation procedure, gives high sensitivity and specificity and plays a major role in substance confirmation . Recently, enantioseparation of ICP in soil was performed by HPLC–MS/MS using an amylose tris(3,5‐dimethylphenylcarbamate) chiral column . However, to the best of our knowledge, there is no report on simultaneous enantioselective determination of ICP and its main metabolite ICPO in rice, soil, and water.…”