Study On Pesticide Residues In Chrysanthemum Morifolium Ramat

Traditional Chinese medicine is characteristic products in China to treat medical illness or improve health. Because of historical reasons and the irrational use, there are residues of pesticides in the soil and water. Consequently pesticides become increasingly important pollutants in Chinese herbal medicine. With health concerns, pesticide residue analysis in herbs has become increasingly important. Meanwhile, with China's entry into WTO and ever-increasing exports, Chinese medicine production has become a major industry for foreign exchange earning. But it is restricted by the problem of pesticide residues. Therefore, detection and control of the pesticide residues in Chinese herbal medicine are imperative.Flos Chrysanthemi is dried tau-inflorescences of Chrysanthemum morifolium Ramat.. It is mainly produced in Tongxiang, Haining and other places of Zhejiang province. Its processing method is drying after steaming or microwave drying. In cultivation process, Chrysanthemum will be attacked by aphids. Because of the irrational use of pesticides (used some strong toxic banned pesticides or excessive dosage pesticides) and the pesticide residues in soil and water, there maybe existed residual pesticides in Chrysanthemum also. In the use of Chrysanthemum,the methods used commonly are soaking, decocting and microwave extraction with water. With the acquisition of effective ingredients, harmful pesticides will also enter the extracts.Due to its oil-rich ingredients, it is difficult to apply common method for determining pesticide residues in Chrysanthemum. Thus, the analysis of pesticide residues has been considered to be a technical problem. Therefore, organic solvent extraction, GPC purification technology and GC-MS combined detection are used in this paper. A method for determining many kinds of pesticide residues was established and the residue in Chrysanthemum in different regions was investigated. The results showed that the average recoveries of this method are 63.75%～109.77% and it is effective for the determination of residual pesticides in Chrysanthemum. This method can also be used for determining the pesticide residues in other oil-rich Chinese medicine. Referenced to related standards, pesticide residues in tested Chrysanthemum samples were below Maximum Residue Limits (MRLs), and there was no significant difference among samples from different regions.Imidacloprid is a commonly used pesticide which can effectively prevent the invasion of aphis to Chrysanthemum. Until now there was no report about its degradation and residue dynamics. To understand its residue dynamics and evaluate the safety, the dynamics of degradation,half-life and final residue were explored using high performance liquid chromatography after spraying imidacloprid in Chrysanthemum. The HPLC analytical method was validated. The linear range was 10～400 ng and the average recovery was 87.49%. The degradation equation was C = 12.353e^-0.2554t with half-life(t_1/2) 2.71d. The results provided a scientific basis for ascertaining a reasonable time to pick its flowers.Study on pesticide residues in Chrysanthemum can be extended to other Chinese medicinal materials , fruits , vegetables, tea, etc. Nowadays, pollution-free cultivation of Chinese medicinal materials is promoted heavily. Under the limited conditions, it is a feasible method to effectively control pesticide residues in Chinese medicinal materials and to ensure the safety and quality of Chinese medicinal materials.