title: Vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction with solidification of floating organic droplet combined with HPLC for the determination of neonicotinoid pesticides.
abstract: A microextraction procedure based on vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction with solidification of floating organic droplet (VSLLME-SFO) for preconcentration of neonicotinoid pesticides, including acetamiprid, clotianidin, nitenpyram, imidacloprid, and thiamethoxam, has been developed. In VSLLME-SFO process, the addition of surfactant (as an emulsifier), could be enhance the mass-transfer from the aqueous solution into the extraction solvent. The extraction solvent could be dispersed into the aqueous by vortex process. Other experimental parameters affected the extraction efficiency, including the kind and concentration of salt, concentration and volume of HCl, kind and concentration of surfactant and its volume, kind and volume of extraction solvent, vortex time and the centrifugation extraction time, were also optimized. The optimum extraction conditions of VSLLME-SFO were 10.00 mL of sample, 0.3% (w/v) Na2SO4, 50 µL of 0.050 mol L(-1) SDS, 1.0 mol L(-1) HCl (400 µL), 150 µL of octanol, vortex time 1 min and centrifugation time 10 min. The sediment phase was analyzed by subjecting it to HPLC using a mobile phase of 25% acetonitrile in water, at a flow rate of 1.0 mL min(-1), and photodiode array detection at 254 nm. Under the optimum extraction conditions, high enrichment factors (20-100 fold) and low limit of detection (0.1-0.5 μg L(-1)) could be obtained. This method provided high sensitivity, low toxic organic solvents used, and simplicity of the extraction processes. The proposed method was successfully applied in the analysis of neonicotinoids in fruit juice and water samples.
authors.affiliation: Creative Chemistry and Innovation Research Unit, Department of Chemistry, Faculty of Science, Mahasarakham University, Mahasarakham 44150, Thailand. Electronic address: jitlada_v@hotmail.com.
authors.forename: Jitlada
authors.initials: J
authors.lastname: Vichapong
authors.forename: Rodjana
authors.initials: R
authors.lastname: Burakham
authors.forename: Supalax
authors.initials: S
authors.lastname: Srijaranai
mesh_terms: D001628:Beverages / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D004655:Emulsions; D005618:Fresh Water / Q000737:chemistry*; D005638:Fruit / Q000737:chemistry*; D006146:Guanidines / Q000032:analysis; D006801:Humans; D007093:Imidazoles / Q000032:analysis; D059627:Liquid Phase Microextraction / Q000379:methods*; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000032:analysis; D010078:Oxazines / Q000032:analysis; D010575:Pesticides / Q000032:analysis*; D011725:Pyridines / Q000032:analysis; D012680:Sensitivity and Specificity; D013501:Surface-Active Agents / Q000737:chemistry; D000077922:Thiamethoxam; D013844:Thiazoles / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D004655:Emulsions; D006146:Guanidines; D007093:Imidazoles; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010078:Oxazines; D010575:Pesticides; D011725:Pyridines; D013501:Surface-Active Agents; D013844:Thiazoles; D014874:Water Pollutants, Chemical; C480342:clothianidin; C464843:nitenpyram; C082359:imidacloprid; C464485:acetamiprid; D000077922:Thiamethoxam
keywords: Extraction; HPLC; Neonicotinoids; Vortex-assisted surfactant-enhanced-emulsification liquid–liquid microextraction