Study On Pesticide Residue Detection And Risk Assessment Of 7 Genuine Medicinal Materials Produced In Sichuan

Pesticides are widely used in the cultivation of traditional Chinese medicine to ensure the yield and quality of products.The registration of pesticides in traditional Chinese medicines has not been paid enough attention,and there is no standard to comply with in planting and cultivation of traditional Chinese medicines when it comes to dealing with diseases and insect pests,which leads to the phenomenon of abuse of pesticides.In addition,the lack standards for pesticide residue limits in traditional Chinese medicine makes it difficult to effectively assess the residue situation.Advancing and guiding the standardization of cultivation in the origin through standards is a more effective measure at present.Thus,the development of testing methods,the selection of testing indicators,the formulation of reasonable limits are very important.At present,domestic pesticide risk assessment of Chinese medicinal materials has been preliminarily carried out,however the research on pesticide residue and risk assessment of many Chinese medicinal materials is insufficient,and some of them are even blank.Besides,the detection of pesticides is not specific and the types of prohibited pesticides tested are not complete.Therefore,this study takes 7 kinds of Sichuan genuine herbs including Alisma orientale,Gardenia jasminoides,Ophiopogon japonicus,Ligusticum chuanxiong,Salvia miltiorrhiza,Pinellia ternata and Houttuynia cordata as the research objects.Here,we have provided an effective technical support for the risk control of exogenous harmful residues and the revision of residue limit standards in traditional Chinese medicine through the following six aspects of research.1.Origin research and sample collectionBased on the genuine herbs produced in Sichuan,this study firstly selected 7representative medicinal materials through comprehensive consideration of the coverage of pesticides,the diversity of substrates,the advantages of market ownership,and the universality of clinical use through a large number of investigations on the production area in the early stage.In-depth investigation and collection of experimental samples are carried out in the genuine area to ensure the representativeness of the test data.2.Study on 143 pesticide residue detection methodsIn this study,143 national banned pesticides and commonly used pesticides were selected as the detection indicators.LC-MS/MS was established to detect 79 pesticides and GC-MS/MS to detect 71 pesticides.The analysis was carried out in multiple reaction monitoring(MRM)mode.Methods of the sample pretreatment and chromatographic conditions were optimized.The method verification results show that the recovery rates of 90.9% of pesticides were between 60% and 140%.The correlation coefficient(r)is greater than 0.99,and the detection limit of most pesticides of the methods is less than 0.01mg/kg,which meets the requirements of trace analysis and detection.Finally,a pesticide multi-residue detection method is established.Among them,the research content of Ophiopogon japonicus belongs to the drafting of the fifth method for the detection of pesticide residue in the four general rules 2341 of the Chinese Pharmacopoeia in 2020 edition.3.Sample testing and risk assessmentThis method was used to test 881 batches of samples of the above 7 kinds of medicinal materials.The results showed that the detection rate of pesticides of each variety was between 84.8% and 100%,and more than 20 kinds of pesticides were detected.Among the pesticides detected,some are pesticides used for planting pests and diseases,and some may be pesticides used in intercropping or rotation.Indicating the use of pesticides in the cultivation of 7 kinds of medicinal materials are more common.Among the commonly used pesticides,the detection rate of carbendazim,chlorpyrifos,and pyrethroids is relatively high,which is generally consistent with the pesticide usage habits in China.Carbofuran,phorate,fipronil,amithiophos and other banned pesticides have been detected from time to time,indicating that some Chinese medicinal materials production areas lack effective supervision on the use and residues of banned pesticides in the country.The point assessment model was used to conduct risk assessment on the pesticide residue detection results of 7 Sichuan genuine herbs.The results showed that only the Houttuynia cordata contained safety risks,and the risks of other varieties were within acceptable limits.Hydrocarbophos is a highly toxic pesticide.It is a broad-spectrum insecticide and acaricide.It has been banned from being used in the cultivation of traditional Chinese medicine by the state.Its residue in Houttuynia should be taken seriously.4.Research on the correlation between decoction pieces and pesticide residuesStatistical analysis shows that the detection results of carbendazim and carbofuran were significantly different between Pinelliae Rhizoma Praeparatum and Pinelliae Rhizoma Praeparatum cum Zingibere et Alumine,Pinelliae Rhizoma Praeparatum and Pinelliae Rhizoma Praeparatum cum Alumine in total of 217 batches,which may be related to the processing technology.We have conducted a more in-depth study on the correlation between the processing technology and the level of pesticide residue.5.Research on the transfer rate of pesticide residues in preparationsAccording to the detection results,the pesticide transfer rate of paclobutrazol in Ophiopogon japonicus,paclobutrazol and chlorpyrifos in Alisma orientale was outstanding,and the pesticide transfer rate was studied.Referring to the "Chinese Pharmacopoeia" 2020 edition,28 production process of preparations containing Ophiopogon japonicus and 60 preparations containing Alisma orientale to investigate the pesticide transfer rate.The LC-MS/MS method was used for analysis.The results showed that the metastasis rate of Paclobutrazol in Ophiopogon japonicus is 72%～103%,and the metastasis rate of paclobutrazol in Alisma orientalis is 38%～63%.At the same time,7 traditional Chinese medicine preparations containing Ophiopogon japonicus were tested.The samples all detected a certain amount of paclobutrazol.It is transferred to the preparation and finally enters the human body,which poses a certain safety hazard.The maximum transfer rate of chlorpyrifos in Alisma orientale is 10%.Although the transfer rate in preparations is not high,but chlorpyrifos is a poisoned pesticide.Besides,the residual amount in Alisma is up to 10mg/kg,and more than 50%of the preparations containing Alisma orientale are used as the original powder in the Chinese Pharmacopoeia 2020 edition.Therefore,it is recommended to complete the limit of chlorpyrifos in Chinese medicine as soon as possible.6.Research on the detection methods of various plant growth regulators in Ophiopogon japonicus.Based on the results of pesticide residue detection,Ophiopogon japonicus was selected as the research object to further explore the use and residues of plant growth regulators in the planting process.Using the LC-MS/MS method,a test for the simultaneous determination of 28 plant growth regulators was established.As a result,a total of 7 plant growth regulators were detected in 110 batches of samples,both in Sichuan and Zhejiang were detected.Among them,the detection rates of 4-nitrophenol sodium and paclobutrazol were 100% and 92.7%,which should be given great attention.In summary,this study was the first to establish a detection method for banned pesticide residues and applied it to 7 kinds of Sichuan genuine herbs;the first comprehensive testing and risk assessment of 7 kinds of Sichuan genuine herbs by 143 established pesticide residue detection methods,and mapped the current status of pesticide residues;the first statistical analysis of pesticide residues in different processed products of Pinellia ternata,and found a correlation between the processing process and pesticides;the first study on the the pesticide transfer rate of Ophiopogon japonicus and Alisma orientale research was carried out,and further explored the detection of paclobutrazol residues in preparations containing Ophiopogon japonicus;the first detection method for multiple plant growth regulators in Ophiopogon japonicus was established,and it was found that plant growth regulators were used during planting through a large number of sample screenings.This study conducted a whole chain analysis of pesticides from medicinal materials to decoction pieces,to preparations,and explored the patterns,risks and transfer rates of pesticide use to provide a reference for the standardized planting of Sichuan genuine herbs and provide new ideas for risk assessment of pesticides in traditional Chinese medicine.