Comparing toxicity and biodegradation of racemic glufosinate and L-glufosinate in green algae Scenedesmus obliquus.

Glufosinate-ammonium, a widely used chiral herbicide, has become the focus of attention because of its toxicity toward non-target organisms and its degradation behavior in the environment. With the introduction of L-glufosinate-ammonium products, the toxicity and environmental behavior of rac-glufosinate-ammonium and L-glufosinate-ammonium have become the subject of increasing interest. The overall goal of this study was to investigate the differences in toxicity and biodegradation of rac-glufosinate-ammonium and L-glufosinate-ammonium in an aquatic organism, Scenedesmus obliquus.

Dissipation Dynamics, Terminal Residues and Dietary Risk Assessment of Two Isomers of Dimethacarb in Rice by HPLC-MS/MS.

Dimethacarb is a carbamate insecticide developed in China that contains 3,5-dimethylphenyl methylcarbamate (XMC) and 3,4-dimethylphenyl methylcarbamate (MPMC) isomers. Dimethacarb has been registered for use in rice in China, but no residue or degradation of dimethacarb in rice has been reported and the maximum residue limits (MRLs) for rice have not been established. A versatile high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed with modified QuEChERS sample preparation to determine two isomers of dimethacarb in rice.

Enantioselective Analysis and Degradation Studies of Four Stereoisomers of Difenoconazole in Citrus by Chiral Liquid Chromatography-Tandem Mass Spectrometry.

Four difenoconazole stereoisomers were well separated on a Superchiral S-OX column. The absolute configurations of the four stereoisomers of difenoconazole eluted in an orderly fashion with the chiral column were confirmed as (2,4), (2,4), (2,4), and (2,4)-difenoconazole, respectively, by single-crystal X-ray diffraction. For the first time, a simple and efficient trace detection method for the determination of residues of the four stereoisomers of difenoconazole in a plant sample by HPLC-MS/MS was developed.