title: Stereoselective quantitation of mecoprop and dichlorprop in natural waters by supramolecular solvent-based microextraction, chiral liquid chromatography and tandem mass spectrometry.
abstract: Liquid chromatography (LC)/tandem mass spectrometry (MS/MS) after supramolecular solvent-based microextraction (SUSME) was firstly used in this work for the enantioselective determination of chiral pesticides in natural waters. The method developed for the quantitation of the R- and S-enantiomers of mecoprop (MCPP) and dichlorprop (DCPP) involved the extraction of the herbicides in a supramolecular solvent (SUPRAS) made up of reverse aggregates of dodecanoic acid (DoA), analyte re-extraction in acetate buffer (pH = 5.0), separation of the target enantiomers on a chiral column of permethylated α-cyclodextrin under isocratic conditions, and detection of the daughter ions (m/z = 140.9 and 160.6 for MCPP and DCPP, respectively) using a hybrid triple quadrupole mass spectrometer equipped with an electrospray source operating in the negative ion mode. Similar recoveries (ca. 75%) and actual concentration factors (ca. 94) were obtained for both phenoxypropanoic acids (PPAs). The quantitation limits were 1 ng L(-1) for R- and S-MCPP, and 4 ng L(-1) for R- and S-DCPP, and the precision, expressed as relative standard deviation (n = 6) was in the ranges 2.4-2.7% ([R-MCPP] = [S-MCPP] = 5 ng L(-1) and [R-DCPP] = [S-DCPP] = 15 ng L(-1)) and 1.6-1.8% (100 ng L(-1) of each enantiomer). The SUSME-LC-MS/MS method was successfully applied to the determination of the enantiomers of MCPP and DCPP in river and underground waters, fortified at concentrations between 15 and 180 ng L(-1) at variable enantiomeric ratios (ER = 1-9).
authors: Department of Analytical Chemistry, Institute of Fine Chemistry and Nanochemistry, University of Córdoba, Edificio Anexo Marie Curie, Campus de Rabanales, 14071 Córdoba, Spain.
authors: C
authors: C
authors: Caballo
authors: M D
authors: MD
authors: Sicilia
authors: S
authors: S
authors: Rubio
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000032:analysis / Q000302:isolation & purification; D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000032:analysis / Q000302:isolation & purification; D002853:Chromatography, Liquid / Q000191:economics / Q000379:methods; D060587:Groundwater / Q000032:analysis; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000191:economics / Q000379:methods*; D010575:Pesticides / Q000032:analysis* / Q000302:isolation & purification; D045483:Rivers / Q000737:chemistry; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry / Q000191:economics / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D010575:Pesticides; D014874:Water Pollutants, Chemical; D015084:2,4-Dichlorophenoxyacetic Acid; C008340:mecoprop; D008456:2-Methyl-4-chlorophenoxyacetic Acid; C010571:dichlorprop