Department of Applied Chemistry, Faculty of Science, University of Johannesburg, P.O. Box 17011, Doornfontein 2028, South Africa
Msagati, T.A.M., Department of Applied Chemistry, Faculty of Science, University of Johannesburg, P.O. Box 17011, Doornfontein 2028, South Africa; Mamba, B.B., Department of Applied Chemistry, Faculty of Science, University of Johannesburg, P.O. Box 17011, Doornfontein 2028, South Africa
The aim of this work was to develop a method for the determination of N-methyl carbamates in water involving hollow fibre supported liquid membrane (HFSLM) and solid phase extraction (SPE) as sample preparation methods. Four N-methyl carbamate pesticides, aldicarb, carbaryl, carbofuran and methiocarb sulfoxide, were simultaneously extracted and analysed by a liquid chromatograph with a diode array detector (LC-UV/DAD) and a liquid chromatograph coupled to a ion trap quadrupole mass spectrometer (LC-ESI-MS). The high performance liquid chromatography (HPLC) separation of carabamate extracts was performed on a C 18 column with water-acetonitrile as the mobile phase. The mass spectrometry analyses were carried out in the positive mode, operating under both the selected ion monitoring (SIM) and full scan modes. The solid phase recoveries of the extracts ranged between 8% and 98%, with aldicarb having the highest recoveries, followed by carbaryl, carbofuran and methiocarb had the lowest recovery. The HFSLM recovery ranged between 8% and 58% and the order of recovery was similar to the SPE trend. Factors controlling the efficiency of the HFSLM extraction such as sample pH, stripping phase pH, enrichment time, stirring speed as well as organic solvent used for entrapment of analytes, were optimised to achieve the highest enrichment factors. © 2012 Elsevier Ltd.
Aldicarb; Analytes; Carbaryl; Carbofurans; Diode array detectors; Enrichment factors; Hollow fibre; Ion traps; LC-ESI-MS; Liquid chromatography-Mass spectrometry; Mass spectrometry analysis; Methiocarb; Mobile phase; N-methyl carbamate; N-Methyl carbamate pesticides; Positive mode; Quadrupole mass spectrometer; Sample pH; Sample preparation methods; Scan mode; Selected ion monitoring; Solid-phase; Solid-phase extraction; Stirring speed; Supported liquid membrane; Acetonitrile; Chromatography; High performance liquid chromatography; Insecticides; Liquid membranes; Mass spectrometry; Organic solvents; Recovery; extraction method; liquid chromatography; mass spectrometry; membrane; pesticide residue; water pollution