Study On The Determination Method Of Pesticide Residues In Fruits

Fruit is essential to our daily life food, it's contains many kinds of vitamin and trace elements which can prevent the body from some diseases. In recent years, the incidence of acute poisoning often was caused by pesticide residues exceeding at home and abroad, which are due to improper using of pesticides. As people's living standards improved, emphasis on food safety has increased. Therefore, the maximum residue limit of pesticide in fruits is increasingly more stringent.The pesticide testing program is also increasing. To break the trade barriers and expanding exports of fruits, the determination of multi-pesticiede residues in fruits is necessary by the advanced equipment.In this paper we established a new method to detect and measure 20 carbamate pesticide residues in fruit. In this method we used acetonitrile to extract and then purified with Carb/NH2 solid phase extraction column, and the targets were detected and measured by high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). In the concentration range from 0.005 mg/kg to 0.100 mg/kg, this method had a good linearity, the correlation coefficients were from 0.9917 to 0.9996. The method was accurate, sensitive and fast.The recoveries of these pesticides at three spiked levels ranged from 57.1% to 120.4% and the relative standard deviations ranged from 4.3% to 20.9%.Method of analysing the residues of eleven kinds of phenoxyacid herbicide residues in fruit has been established. In this method we used acetone-hexane to extract pesticides and derivatived them by butanol-sulfuric acid, then purified and analyzed them by automated online gel chromatography-gas chromatography/mass spectrometry (GPC-GC/MS).This method had a good linearity, the correlation coefficients were from 0.9987 to 0.9999 when the concentration of the 11 pesticides was from 0.010 mg/kg to 1.000 mg/kg. Recoveries from spiked samples rangeed from 65.7% to 111.5% and the relative standard deviations (RSD) were from 3.0% to 11.9%. All of this showed that this method was detection sensitivity and good at separation, recovery, reproducibility. It's satified with the demands of the limitation of pesticide residue analysis and the needs of real-time monitoring of pesticide residues.In this experiment we pre-treated the samples and optimized the conditions of apparatus. Used acetone-hexane (1+9, v/v) to extract and florisil solid phase extraction cartridges of comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry to detect and measure 34 kinds of organochlorine and pyrethroid pesticide residues was more effective and faster than traditional one-dimensional chromatography-mass spectrometry. This method had a good linearity for the targets, the correlation coefficients were from 0.9898 to 1.000 when the concentration of them was from 0.001 mg/kg to1.000 mg/kg. And the recoveries of the 34 pesticides was from 60.1% to115.0% with the relative standard deviation(RSD) from 2.5% to 13.7%, which was meet the requirement of pesticide residue analysis. The results of this method afforded an effective and accurate resort to detect and measure organochlorine and pyrethroid pesticide residues in fruit. It's helping to breakthrough the international trade barriers and expanding fruit exports.