Simultaneous enantioselective determination of fenamiphos and its two metabolites in soil sample by CE

Abstract

The enantioseparation of fenamiphos and its two main metabolites (fenamiphos sulfoxide and fenamiphos sulfone) were simultaneously achieved by CE by using a dual CD system. A mixture of 25 mM carboxymethyl-beta-CD and 10 mM hydroxypropyl-alpha-CD was added to the acetic acid/ammonia (ionic strength=50 mM, pH 5) buffer and was suitable for the baseline resolution of all stereoisomers of analytes. A further addition of 5% methanol to the BGE increased significantly the resolution between the diastereoisomers of fenamiphos sulfoxide. An overimposed pressure (0.2 psi) was applied during the analysis in order to have better peak efficiencies and small run time. The composition of the sample solvent was found to be a crucial parameter. An amount of 15% MeOH added to the sample was a good alternative to ensure the total solubility of fenamiphos and the baseline separation of fenamiphos sulfoxide enantiomers. The extraction of pesticides from soil samples was also investigated. A methanolic extraction allowed recovering 50-75% of pesticides, which were detected by CE at the parts per million concentration level (3-100 mg/kg) with a good precision (5.1-13.2% RSD). This method was applied to soil samples and was found to be suitable to monitor the enantiomeric degradation of fenamiphos in environmental samples.

Enantiomeric Separation of Original Heterocyclic Organophosphorus Compounds in Supercritical Fluid Chromatography

“…Another example is that of modern insecticides derived from chemical warfare agents, as a wide array of them is based on a chiral phosphorus atom. Chiral separation for some of these P‐chiral pesticides was reported using either gas chromatography with cyclodextrin or amino‐acid stationary phases, reversed‐phase or normal‐phase liquid chromatography on Pirkle‐type or polysaccharide stationary phases or capillary electrophoresis with cyclodextrin chiral selectors in the buffer . Naubron et al reported on the normal‐phase HPLC enantioseparation of original P‐chiral phenylphosphine–borane complexes .…”

“…Chiral separation for some of these P-chiral pesticides was reported using either gas chromatography with cyclodextrin or amino-acid stationary phases, [6][7][8] reversed-phase or normalphase liquid chromatography on Pirkle-type or polysaccharide stationary phases [9][10][11][12][13] or capillary electrophoresis with cyclodextrin chiral selectors in the buffer. [14][15][16][17] Naubron et al reported on the normal-phase HPLC enantioseparation of original P-chiral phenylphosphine-borane complexes. 18 The separation was achieved on a cellulose tris-(p-methylbenzoate) stationary phase.…”

Enantiomeric separation of 1,3‐dimethylamylamine by capillary electrophoresis with indirect UV detection using a dual‐selector system

“…Up to date, only two papers focused on the enantiomeric separation of cationic compounds by CE employing the indirect UV-VIS detection have been published. Free amino-acids were enantioseparated with (-)-(18-crown-6)-tetracarboxylic acid as a CS when chrysoidine [34] and creatinine [35] were used as chromophoric additives.…”

PDMS microchip coated with polydopamine/gold nanoparticles hybrid for efficient electrophoresis separation of amino acids

“…The phenomenon can be explained by the fact that enhanced ionic strength of running buffer usually leads to a slower EOF, weaker adsorption of modifiers and an increased Joule heat (a source of band broadening and migration time reproducibility problems) [52], and accordingly induces a lower efficiency, sensitivity and stability [51]. Since ideal conditions must be a compromise between stable ionic strength and minimal Joule heating [53], 5.0 mM was selected as the optimum buffer concentration.…”