| China is the birthplace of Chinese herbal medicine, we occupies the monopoly superiority on the traditional Chinese medicine resources. But in recent years, due to excessive pesticide residues and other reasons, the Chinese herbal medicine exported is seizing and holding in custody many times in Europe, the United States and other countries markets. The pesticide residue pollution has become a barrier to move toward the world for Chinese herbal medicine and Chinese patent medicine, also it is one of important and urgent problems in current traditional Chinese medicine production.The purpose of this paper is to research the method of the pesticide residue analysis in Chinese herbal medicine and its preparation, the actual content includes:Chapter 1:A brief introduction of basic knowledge of pesticides and the types of banned pesticides in Chinese herbal-medicine is presented. A review concerning the analysis and determination development of pesticide residues in samples, analytical present situation of pesticide residues in Chinese herbal medicine, as well as the existence question of pesticide residues in Chinese herbal medicine are presented. The paper identified its topic selection on the basis of this review.Chapter 2:A pretreatment conditions were optimized for the extraction and gas chromatography-electron capture detector (GC-ECD)screening of 5 pyrethroid pesticides from Chinese herbal medicines. Pesticide residues were extracted for 3 times from Chinese herbal medicines amples with 30mL mixture solvent of acetone-petroleum ether(1:4). Extract after concentrating was cleaned up with a mixture column by 120mL of ethyl acetate-petroleum ether (10:90) eluting, determined by GC-ECD. The limits of detection of 5 pyrethroid pesticides were range from 0.0001 to 0.0009μg/mL. The average recoveries were range from 72.91% to 96.71%, the RSD were range from 1.2% to 9.2%, the method met the requirements of pesticide analysis. Deltamethrin was mostly found in 5 pyrethroid pesticides with a maximum detection volume of 0.032mg/kg. Through detection, we found out pesticide residue existent in all 9 kinds of herds, except Fructus viticis and radix puerariae. A larger toxic solvents-ether was replaced in the method,2 kinds of pyrethroid pesticide were increased, the method was accurate and multi-residue.Chapter 3:A multiresidue analysis method based on matrix solid-phase dispersion (MSPD) was optimized by orthogonal experimental design for pretreatment conditions and GC-ECD screening simultaneously of organochlorine pesticides and pyrethroid pesticides, and the optimum conditions were using florisil and neutral alumina (1:1) mixture with a total of 3g as solid phase, elution solvent was acetone-n-hexane (3:7) 50mL,0.5 mL water was added. The limits of detection of 18 pesticides were range from 0.00003 to 0.002μg/mL, average recoveries were range from 73.31% to 137.34%, the RSD were range from 1.6% to 18.9%, the method met the requirements of pesticide analysis.9 kinds of Chinese herbal medicines were determined, organochlorine pesticides were detected in all samples, pyrethroid pesticides were detected in some samples. All detectable amount all didn't exceed the limited amount of Chinese Pharmacopoeia, but some was close to Pharmacopoeia requirements. Compared with the pharmacopoeia method, this method was simple, accurate and rapid, solvent consumption is small, the simultaneous determination of various types of pesticides were realized.Chapter 4:A multiresidue analysis method was optimized for pretreatment conditions and based on MSPD-GC-MS screening simultaneously of 25 kinds pesticides including organochlorine pesticides, organophosphorus pesticides, pyrethroid pesticides and pesticide containing nitrogen from Chinese patent medicines, an appropriate purification method was chose to determine all pesticides one time by GC-MS.First the sample joined 0.5mL water, and took florisil and neutral alumina (1:1) mixture with a total of 3g as solid phase, 50mL acetone-n-hexane (3:7) eluted, and then 15mL acetone-methanol (1:1) eluted, collected all the eluate, after concentrating and fixed constant volume, the sample was detected by GC-MS.The limits of detection of 25 pesticides were range from 0.00003 to 0.002μg/mL, average recoveries were range from 71.38% to 120.64%, the RSD were range from 3.1% to 17.8%, the method met the requirements of pesticide analysis. Each 5 batches of two kinds of Chinese patent medicines were detected, organochlorine pesticides were found in most of the batches, but the detectable amount was lower, and organophosphorus pesticide were not found, deltamethrin was mostly detected.In addition, metalaxyl was only detected from Nuanweishule tablets, and detectable amount was very low. This method was time-saving, simple, accurate and rapid, solvent consumption is small, the mass spectrum was more accurate.Chapter 5:A summary of the paper was presented, and forecasted the future trend. |
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