title: Combination of graphene oxide-based solid phase extraction and electro membrane extraction for the preconcentration of chlorophenoxy acid herbicides in environmental samples.
abstract: Combination of different extraction methods is an interesting and debatable work in the field of sample preparation. In the current study, for the first time, solid phase extraction combined with electro membrane extraction (SPE-EME) was developed for ultra-preconcentration and determination of chlorophenoxy acid herbicides in environmental samples using capillary electrophoresis (CE). In the mentioned method, first, a 100mL of chlorophenoxy acid herbicides (2-methyl-4-chlorophenoxyacetic acid (MCPA), 2-(2,4-dichlorophenoxy) propanoic acid (2,4-DP) and 2-(4-chloro-2-methylphenoxy) propanoic acid (MCPP)) was passed through a column of graphene oxide as a solid phase, and then the adsorbed herbicides were eluted by 4.0mL of 8% acetic acid (HOAC) in methanol. Then, the elution solvent was evaporated and the herbicides residue was dissolved in 4.0mL of double distilled water (pH 9.0). Afterwards, the herbicides in 4.0mL of the aqueous solution were transferred to an EME glass vial. In the EME step, the herbicides were extracted from the sample solution into the basic acceptor solution (pH 13.0) under electrical potential, which was held inside the lumen of the fiber with 1-octanol as the supported liquid membrane (SLM). Under the optimized conditions, high enrichment factors were obtained in the range of 1950-2000. The limits of quantification (LOQs) and method detection limits (MDLs) were obtained in the range of 1.0-1.5 and 0.3-0.5ngmL(-1), respectively. Finally, the performance of the present method was evaluated for extraction and determination of chlorophenoxy acid herbicides in environmental samples.
authors.affiliation: Department of Chemistry, Faculty of Sciences, Shahid Beheshti University, G.C., PO Box 193965 4716, Evin, Tehran, Iran.
authors.forename: Hadi
authors.initials: H
authors.lastname: Tabani
authors.forename: Ali Reza
authors.initials: AR
authors.lastname: Fakhari
authors.forename: Abolfath
authors.initials: A
authors.lastname: Shahsavani
authors.forename: Mohammad
authors.initials: M
authors.lastname: Behbahani
authors.forename: Mani
authors.initials: M
authors.lastname: Salarian
authors.forename: Akbar
authors.initials: A
authors.lastname: Bagheri
authors.forename: Saeed
authors.initials: S
authors.lastname: Nojavan
mesh_terms: D020003:1-Octanol / Q000737:chemistry; D019075:Electrophoresis, Capillary; D006108:Graphite / Q000737:chemistry*; D006540:Herbicides / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D010642:Phenoxyacetates / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*; D015203:Reproducibility of Results; D012107:Research Design; D045483:Rivers / Q000737:chemistry; D052616:Solid Phase Extraction / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D006540:Herbicides; D008567:Membranes, Artificial; D010642:Phenoxyacetates; D014874:Water Pollutants, Chemical; D006108:Graphite; D020003:1-Octanol
keywords: Capillary electrophoresis; Chlorophenoxy acid herbicides; Electro membrane extraction; Experimental design; Solid phase extraction