Determination Of Organophosphorus Pesticides In Fish Tissue By Microextraction Techniques

The organophosphorus pesticides(OPPs) have been widely used in China due to their low price and effective ability to kill pets. However, along with the benefits we have, the use of OPPs in agricultural and plant protection practices have caused extensive environmental pollution which might pose a potential risk for human health. The pollution of pestcides residues have been a serious problem in many aspects of daily life. How to control and monitor the pollution of pesticides has becoming a big issue, also aroused attentions of each governments.Both liquid-phase microextraction (LPME) and solid-phase microextraction (SPME) are novel sample pretreatment techniques developed in nineties of last century. Both of these two techniques are simple, fast and inexpensive, and combine extraction and concentration into one step. They are solvent-free or use very little solvent, which addresses the requirements of environmentally friendly pretreatment technology. In this study, LPME and SPME techniques were used for the determination of OPPs in fish tissue.Firstly, the method for the determination of OPPs in fish tissue by hollow fiber LPME technique was developed. Many parameters such as the types of hollow fibers, the extraction solvent and its solvent volume, agitation speed and extraction time were optimized. The obtained optimum experimental conditions were: extraction solvent: 30μL o-xylene extraction solvent, agitation speed: 500rpm, extraction time:30min, and then the extract was injected for GC-MS analysis. The method evaluation results showed that good linearity were observed in the range of 20-500 ng/g, limits of detection (LODs) were in the range of 2.11-4.54 ng/g, and the repeatability(expressed as R.S.D)were less than 19%.Further more, the method for determination of OPPs in fish tissue by SPME technique were also established. The effects of the types of fibers, the pH of the sample solution, extraction time, stirring rates and desorption temperature were investigated. Under the optimum experimental conditions (PDMS fiber, extraction time:45min, stirring rate:1500rpm, desorption time:3min), the linear range, recovery and repeatability of the method were showed satisfactory results. Compared with the traditional method for the determination of OPPs, the two methods built up in this study are much simpler, since the new methods eliminated the step of Gel Permeation Chromatography (GPC), which not only saves the cost, but also shorten the analytical cycles and meet the requirements of daily detection of OPPs in fish tissue.