Simultaneous determination of enantiomers of carfentrazone‐ethyl and its metabolite in eight matrices using high‐performance liquid chromatography with tandem mass spectrometry

Abstract

A reversed-phase simultaneous determination method for the enantiomers of carfentrazone-ethyl and its metabolite carfentrazone in agricultural and environmental samples was established using high-performance liquid chromatography-tandem mass spectrometry. A complete enantioseparation of carfentrazone-ethyl and its chiral metabolite carfentrazone enantiomers was obtained using a chiral column. The absolute configuration and specific optical rotation of carfentrazone-ethyl and carfentrazone enantiomers were first confirmed as peaks 1, 2, 3, and 4: S-(+)-carfentrazone, R-(-)-carfentrazone, S-(-)-carfentrazone-ethyl, and R-(+)-carfentrazone-ethyl, respectively. The specificity, matrix effect, linearity, precision, accuracy, and stability were surveyed to evaluate the feasibility of the method. The mean recovery was in the range of 77.5-102.8% with relative standard deviations of 0.4-9.8% for the samples. The limits of detection of the enantiomers were evaluated as 0.7 to 6.0 μg/kg, and the limits of quantification were 2.5 to 20 μg/kg. The stereoselective degradation of carfentrazone-ethyl and carfentrazone in rice plant was investigated, and there was no clear enantioselectivity for carfentrazone-ethyl. As for carfentrazone, the enantiomer fractions value reached 0.85 at 7 days after spraying. The developed method was simple and reliable enough for the corresponding risk assessment of carfentrazone-ethyl and its metabolite enantiomers in crop plants, cereal grains, and soil samples.

Stereoselective degradation behaviour of carfentrazone-ethyl and its metabolite carfentrazone in soils

“…The injection volume and column temperature were 5 mL and 35 C, respectively. Gradient elution was adopted and the elution order of four compounds was S-(+)-carfentrazone, R-(À)-carfentrazone, S-(À)-carfentrazone-ethyl and R-(+)-carfentrazoneethyl, respectively 22 An electronic spray ion source with positive ion (ESI+) ionization in the MRM mode. The capillary voltage was 4.5 kV.…”

“…Correspondingly, the quantitative ion pair of carfentrazone was m/z 401.00 > 383.90, while the qualitative ion pair was m/z 401.00 > 365.90 and m/z 401.00 > 345.85. 22 2.7 Method validation 2.7.1 Standard curves. Individual standard solutions (1000 mg L À1 ) in methanol of carfentrazone-ethyl and carfentrazone enantiomer were diluted to serial concentrations (5, 10, 50, 100, 500 and 1000 mg L À1 ) of mixed standard solutions with methanol.…”

Enantioselective residue analysis of oxathiapiprolin and its metabolite in tea and other crops by ultra‐high performance liquid chromatography–tandem mass spectrometry

“…Furthermore, oxathiapiprolin has one asymmetric carbon center and consists of two enantiomers, as shown in Figure 1; at present, it is not clear which enantiomer is the active one. Although, there have been many reports on the analysis of chiral pesticide residues [4,5,[33][34][35][36][37], there have been no reports on the differences between enan-tiomers during residual analysis or studies of dissipation behavior, or on the enantioselective analysis for oxathiapiprolin residues in different samples. Thus, it is critical to consider the behaviors carefully and to establish a method for residue analysis of oxathiapiprolin enantiomers.…”

Comparative analysis of nucleosides, nucleobases, and amino acids in different parts of Angelicae Sinensis Radix by ultra high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry

“…The matrix effect was evaluated using the slope ratio of calibration curves of standards in solvent and matrix‐matched solutions . The matrix does not suppress or enhance the response of the MS when the slope ratio was 1, otherwise denote ionization suppression (< 1) or enhancement (> 1) .…”

“…Chemical standards including thymine (1), thymidine (2), 2 ′ -deoxyuridine (3), 2 ′ -deoxyguanosine (4), guanine (5), cytidine (6), 2 ′ -deoxycytidine (7), cytidine-5 ′ -monophosphate (8), leucine (9), phenylalanine (10), tryptophan (11), γaminobutyric acid (12), methionine (13), proline (14), valine (15), tyrosine (16), alanine (17), hydroxyproline (18), gluta-F I G U R E 2 Chemical structures of the 21 nucleosides, nucleobases and amino acids mate (19), glutamine (20), and asparagine (21) were all purchased from Sigma (St. Louis, MO, USA). The purity of each reference compound was over 98% determined by HPLC analysis.…”