The Application Of Electrospunpolymer Nanofibers For Determination Of Organophosphorus、Pyrethroid Pesticides Residues

The pesticides in atmosphere, soil, waters, organism and food cause lots of negative influences on humanity. It is urgent to reduce the negative effects not only by means of researching efficient, low toxcity, and low persistant pesticides and improving spraying technology, but also developing cheap, rapidly, low organic solvents sample pre-treatment and high sensitive determination methods. It can provide stronggurantee for food and environment security of humanity.We investigated preliminarily polystyrene nanofibers as solid extraction materials. Polystyene nanofibers facilitate weak polarity bing able to absorb pesticides through the solubility in different solvents. Parameters influencing performane of fiber, such as packing amount(at least2.0mg), extracted times(at least3times), and velocity (0.5mL/min) can be determined initially through pre-test of extracting methidathion solution(1mL,5mg/L,17.5%methonal) by tiny nanofiber column.Electrospunpolymer nanofibers were used in the determination of five organophosphorus residues by HPLC. A high performance liquid chromatography (HPLC) was developed for the determination of five organophosphorus pesticides with UV detector, including methidathion, Malathion, phoxim, profenofos and chlorpyrios, in cabbage samples. An electrospunpolymer nanofiber loaded into a tiny tip was used for solid phase extraction materials due to its less fiber amount but large surface areas as well as strong absorption ability. The five organophosphorus pesticides in cabbage samples were directly extracted with the fiber and eluted by methanol. Parameters of influencing the performance of the fiber, such as extracted times, extracted solutions, elutions and pH were investigated. Under the optimized conditions, the maximun absorption capacities of the fiber for methidathion, Malathion, phoxim, profenofos, and chlorpyrios were2.9,3.5,5.6,3.7, 7.8μg/mg, respectively. The five organophosphorus pesticides of three concentration standard solutions were extracted by nanofibers, and the extraction recoveries were68%-97%with RSDs of1.6%-4.7%. The calibration curves showedgood linearity in the concentration range of0.05-10for methidathion,0.5-10for Malathion and0.1-10for rest of analytes. The limit of detection ranged from0.02to0.1mg/kg for five organophosphorus pesticides. The spiked recoveries were in the range of65%-93%with RSDs of1.6%-4.0%. The method was effective, simple and sensitive for detection multiple organophosphorus pesticides. The result also indicated that, compared with usual liquid-liquid extraction and solid phase extraction, the present method offers the advantages low consumption of organic solvent and less harm to environment and humanity.Electrospunpolymer nanofibers were used as materials of solid phase extraction for determination of five pyrethroid pesticides bygas chromatography. The pyrethroid pesticides in tea sample were directly extracted with the fiber, and the target compounds were monitored by agas chromatography with electron capture detector. Parameters of influencing the performance of the fiber were investigated. Under the optimized conditions, the maximun absorption capacities of the fiber for bifenthrin, permethrin, fenvalerate, deltamethrin, and fenpropathrin were7.8、7.5、7.2、6.6、7.0μg/mg, respectively. The five pyrethroids of three concentration standard solutions were extracted by nanofibers. The extraction recoveries were65.5%-89.0%, RSD1.2%-3.0%. Tea samples sprayed five pesticides were determined with above method and then the extraction recoveries were61.3%-87.1%, RSD0.9%-2.8%. The limits of detection (LODs) were in the rang of1.0×10-4-1.0×10-2mg/kg. Compared to C18sorbent, this method has been used for detection of multiple pyrethroid pesticides in tea samples, and proved to be cheap, simple and used less organic solvent.