title: Development of a simple combining apparatus to perform a magnetic stirring-assisted dispersive liquid-liquid microextraction and its application for the analysis of carbamate and organophosphorus pesticides in tea drinks.
abstract: This study introduced a simple combining apparatus for performing a magnetic stirring-assisted dispersive liquid-liquid microextraction (MSA-DLLME) for the detection of trace carbamate and organophosphorus pesticides in tea drinks coupled with high performance liquid chromatography. The simple combining apparatus was made up of a sample vial and a cut plastic dropper. The bulb end of the cut plastic dropper was inserted into the neck of the sample vial and the open tip end of the plastic dropper was then cut to an appropriate length. The combining apparatus made was then used to perform the MSA-DLLME. In this experiment, 1-octanol was injected into the tea drink sample solution and the extraction process accelerated by magnetic agitation. The sample solution turned clear and separated into two layers after leaving it alone for several minutes. The cut plastic dropper was gently put down into the sample vial, and then the liquid level of the sample solution elevated up to the tip of the plastic dropper for the collection of low-density extractant. Finally, the collected extractant was drawn out by a microsyringe and injected into the high performance liquid chromatography-diode-array detector for analysis. A series of extraction parameters were investigated and optimized. Under the most favorable conditions, high enrichment factors were obtained for carbofuran, carbaryl and isocarbophos (between 130 and 185). The limits of detection (S/N=3) were in the range of 0.13-0.61 μg L(-1), and the relative standard deviation varied below 7.8% (n=5). Additionally, good recoveries were obtained between 79.4% and 114.4% in the three tea drinks. The simple combining apparatus utilized in this MSA-DLLME method was shown to be economical, fast, and convenient for the collection of low density extractant.
authors.affiliation: Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Institute of Environmental Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, China.
authors.forename: Xiuhong
authors.initials: X
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Cheng
authors.forename: Hongbin
authors.initials: H
authors.lastname: Zhou
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Cheng
mesh_terms: D002219:Carbamates / Q000032:analysis*; D055590:Electromagnetic Phenomena; D059627:Liquid Phase Microextraction / Q000295:instrumentation / Q000379:methods*; D009943:Organophosphorus Compounds / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D013662:Tea / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D002219:Carbamates; D009943:Organophosphorus Compounds; D010575:Pesticides; D013662:Tea; D014874:Water Pollutants, Chemical
keywords: Carbamate and organophosphorus pesticides; Combining apparatus; High performance liquid chromatography; Magnetic stirring-assisted dispersive liquid–liquid microextraction; Tea drinks