Study on a highly sensitive method for determination of pesticide resieues in tra

Le Huong Ly THAI NGUYEN UNIVERSITY OF AGRICULTURAL AND FORESTRY ADVANED EDUCATION PROGRAM    BACHELOR THESIS STUDY ON A HIGHLY SENSITIVE METHOD FOR DETERMINATION OF PESTICIDE RESIDUES IN TEA BY GAS[.]

THAI NGUYEN UNIVERSITY OF AGRICULTURAL AND FORESTRY ADVANED EDUCATION PROGRAM ……    …… BACHELOR THESIS STUDY ON A HIGHLY SENSITIVE METHOD FOR DETERMINATION OF PESTICIDE RESIDUES IN TEA BY GAS SPECTROMETRY (GC/MS) Full Name : LE HUONG LY Study Mode : Full time Major : Food Technology Falculty : Advance Education Program Batch : 2016 - 2020 Supervisor : Dr Vu Thi Hanh Thai Nguyen, 8-2020 Thai Nguyen University of Agriculture and Forestry Degree Program Engineer of Food Technology Student name Le Huong Ly Student ID DTN 1653170006 Thesis Title STUDY ON A HIGHLY SENSITIVE METHOD FOR Supervisor(s) DETERMINATION OF PESTICIDE RESIDUES IN TEA Dr Vu Thi Hanh - Thai Nguyen University of Agriculture and Forestry, Vietnam Supervisor’s signature Abstract: Using your high sensitivity to analyze the three chemical compounds in tea simultaneously: Chlorpyrifos, α-Endosulfan, Bifenthrin The reality of the method is that many substances can be analyzed at the same time, with low concentration and detection limit and low quantitative limit The value of standard addition at the detection limit is 10µg/kg with S/N greater than and there is always one parent ion and daughter ions in accordance with criteria of 2002/657/EC From the results survey above, it shown that the method of determined active substances by gas chromatography system of mass spectrometry GC-MS with the following results: LOD of the analysis method of is 10µg/kg, limited limit amount (LOQ) equals 30µg/kg The average recoveries of analyte were in the range of 95-105% with linear regression coefficient r2≥0.998 and the variation is less than 10% From the above analysis results, it can be confirmed this method is fast, accurate and reliable for analyzing active substances in tea Keywords: GC-MS, tea, Chlorpyrifos, α-Endosulfan, Bifenthrin Number of pages: Date of submission: 51 17/08/2020 ACKNOWLEDGMENTS In fact, there is no success that is not associated with the support or help of more or less, directly or indirectly from others To complete this thesis, firstly, I would like to express my sincere thanks and deep gratitude to the University Administrations, the leaders of the Faculty of Biotechnology - Food Technology, the lecturers of the Advanced Education Program Office, TUAF helped and gave me useful advices during the course of my thesis And especially, I would like to sincerely thank Dr Vu Thi Hanh paid attention to helping and enthusiastically guiding me to successfully complete this thesis I would like to express my deep thanks to The center for technical services and professional training in agroforestry-fishery quality - Thai Nguyen, of Thai Nguyen Department of Agriculture, Forestry and Fishery Quality Assurance (Code: VILAS 1098; Location: Dong Quang ward, Thai Nguyen city, Thai Nguyen province), the staffs working in the center paid attention and helped Due to limited reasoning, practical experience and limited time, the report can not avoid shortcomings, I look forward to receiving your comments so that I can learn more and complete the report and achieve the best results Once again, I would like to sincerely thank and wish all the best for the health and the success in your noble career We wish our university achieved more success in education and more development Sincerely, Le Huong Ly i TABLE OF CONTENT ACKNOWLEDGMENTS i TABLE OF CONTENT ii LIST OF TABLES iv LIST OF FIGURES v LIST OF ABBREVIATIONS vi PART I INTRODUCTION 1 Overview 1.1 Rerseach rationale 1.2 Research’s objective 1.3 Research question 1.4 Limitations PART II DOCUMENT REVIEW 2.1 Introduction about tea 2.1.1 Growth of tea 2.1.3 Benefits of tea 2.2 Plant protection drugs 2.2.1 Important roles of plant protection drugs 2.2.2 Some plant protection drugs used for tea 2.2.3 Maximum allowed residue 2.3 Some methods for determination pesticide in tea 10 2.3.1 Traditional method: Quantitative analysis method (Ministry of Agriculture and Rural Development (2013) 10 2.3.2 QUECHERS method 11 2.4 Gas chromatography - mass spectrometry GC-MS 13 2.4.1 Principle 14 2.4.2 Structure of GC-MS system 15 PART MATERIALS, EQUIPMENT AND METHODS 19 ii 3.1 Research scope 19 3.2 Research contents 19 3.3 Chemical and Equipment 19 3.3.1 Chemicals 19 3.3.2 Equiment 19 3.4 Methods 20 3.4.1 Preparation of sample and standard 20 3.4.2 Conditions to run the machine GC/MS 24 3.4.3 Sample injection order 26 3.4.4 Evaluation of this method 28 PART IV RESULTS AND DISCUSSION 32 4.1 Limit of detection and limit of quantification 32 4.2 Linearity: 33 4.3 Repeatability - Recovery 36 4.4 Reproducibility: 37 PART V CONCLUSION 39 REFERENCE 40 iii LIST OF TABLES Table 3.4.1a: Concentration and spiked samples 10ppm (µl) to prepare the sample as a calibration curve 22 Table 3.4.1b: Concentration and spiked samples 10ppm (µl), 2ppm (µl) to prepare for tea sample 23 Table 3.4.2: MS condition 26 Table 4.1a: Limit of Detection and Quantification 33 Table 4.1b: The result of reliability evaluation of LOD value 33 Table 4.2: The result of concentration, peak area and the correlation coefficient of linear value 34 Table 4.3: The result of the repeatability and the recovery 37 Table 4.4: The result of the reproducibility 38 iv LIST OF FIGURES Figure 3.3.2: GC-MS equipment 20 Figure 4.2.1a: Chromatography of Chlorpyrifos 34 Figure 4.2.1b: Calibration curve of Chropyrifos 35 Figure 4.2.2a: Chromatography of α-endosulfan 35 Figure 4.2.2b: Calibration curve of α-endosulfan 35 Figure 4.2.3a: Chromatography of Bifenthrin 36 Figure 4.2.3b: Calibration curve of Bifenthrin 36 v LIST OF ABBREVIATIONS %R : Recovery ACN : Acetonitril ADI : Acceptable Daily Intake AOAC : Assosiation of Official Analytical BYT : Ministry of Health Cd : Cadimi Code : Plant protection drug code CODEX : The International Food Standardization Committee EMRL : Extraneous Maximum Residue Limit ERG : Eagle Rock Global EU : European Union FDA : Food and Drug Administration GC/MS : Gas Chromatography - Mass Spectrometry HPLC : High performance liquid chromatography IEC : International Electrotechnical Commission IP : Identification point LD : Lethal Dose LOD : Limit of detection LOQ : Limit of quantification MeOH : Methanol MgSO4 : Magnesium sulfate MRLs : Maximum residue Limits Pb : Lead PE : Petrolium ether ppb : Part per billion ppm : Part per million vi PSA : Prostate- Specific Antigen QUECHERS : Quick, Easy, Cheap, Effective, Rugged and Safe RSD : Relative Standard Deviation S/N : Signal to noise ration Sr : Repeatability TCVN : Vietnamese Quality TUAF : Thai Nguyen University of Agriculture and Forestry USCG : United States Coast Guard Vitamin A : Retinol Vitamin B1 : Thiamine Vitamin B2 : Riboflavin Vitamin B3 : Niacin, Vitamin PP Vitamin C : Acid Ascorbic WHO : World Health Organization vii PART I INTRODUCTION Overview 1.1.Rerseach rationale Vietnam is a developing country, and it is inevitable that the agricultural sector will account for a high proportion in the economic sector Therefore, the use of plant protection chemicals to prevent pests, diseases, insects, mice, termites, etc It was clearly that there are many benefits of using pesticides bring things for different types of agricultural products At present, it is estimated that up to 200 out of 5000 pesticides directly harm human health However, how to make farmers spray at the right dose and safety for themselves and users is another important story Currently, there are many rumors about the quality of agricultural products and plants sprayed with pesticide doses, affecting consumers' health and safety, making buyers confused about their choices But the correct use also depends on the level of knowledge of people in each region Therefore, it is necessary to strictly control the use of safe and effective plant protection drugs to minimize the harmful effects on human health and the ecological environment This is a matter of current concern Current urgent work is to control the level of pesticide residues in food in general and tea in particular Tea is a common industrial crop in the community, so tea farmers often use pesticides as a treatment for pest control and increase productivity Residues of plant protection drugs in crops are not necessary, but