title: Online microchannel preconcentrator for carbofuran detection.
abstract: A simple and rapid online microchannel preconcentrator coupled with an amperometric detection for the analysis of carbofuran using polyethylene glycol coated onto magnetic particle (PEG-magnetic particles) sorbents was developed. This simple-to-prepare microchannel preconcentrator used an external magnet to retain the PEG-magnetic particle sorbents inside the microchannel. Under optimum conditions, the system provided two linear ranges, from 0.01 to 10.0 mg L(-1) and from 10.0 to 130.0 mg L(-1) with a limit of detection of 8.7 ± 0.1 μg L(-1). The microchannel preconcentrator provided very good stability; it can be used for up to 326 consecutive injections of 5.0 mg L(-1) carbofuran with a relative standard deviation of less than 3%. The developed system provided a good microchannel-to-microchannel and a good electrode-to-electrode reproducibility (n = 6, %RSD < 1). It also provided an excellent selectivity when it was tested with two other carbamate pesticides, carbaryl and methomyl, with a 43 and 256 times higher detection sensitivity for carbofuran, respectively. The developed system was successfully applied to detect carbofuran in surface water samples obtained near vegetable plantation areas. The concentrations of carbofuran in these samples were found to be in the range of non-detectable to 0.047 ± 0.001 mg L(-1). The developed system is easy to operate and easy to couple with other analytical instruments and it could be easily adapted for the analysis of other polar organic contaminants.
authors.affiliation: Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Charinrat
authors.initials: C
authors.lastname: Siritham
authors.forename: Chongdee
authors.initials: C
authors.lastname: Thammakhet
authors.forename: Panote
authors.initials: P
authors.lastname: Thavarungkul
authors.forename: Proespichaya
authors.initials: P
authors.lastname: Kanatharana
mesh_terms: D012721:Carbaryl / Q000032:analysis; D002235:Carbofuran / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D060328:Magnetic Phenomena; D008724:Methomyl / Q000032:analysis; D009862:Online Systems / Q000295:instrumentation*; D010575:Pesticides / Q000032:analysis*; D011092:Polyethylene Glycols / Q000737:chemistry; D012680:Sensitivity and Specificity; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D010575:Pesticides; D014874:Water Pollutants, Chemical; D008724:Methomyl; D011092:Polyethylene Glycols; D012721:Carbaryl; D002235:Carbofuran