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 DETERMINATION OF PESTICIDE RESIDUES IN TEA Supervisor(s) 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 3 and there is always one parent ion and 3 daughter ions in accordance with criteria of 2002/657/EC. From the results survey above, it shown that the method of determined 3 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 3 active substances in tea. Keywords: GC-MS, tea, Chlorpyrifos, α-Endosulfan, Bifenthrin Number of pages: 51 Date of submission: 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 agro- forestry-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. Introduction about tea.
Growth of tea. Benefits of tea. Plant protection drugs. Important roles of plant protection drugs.
Some plant protection drugs used for tea. Maximum allowed residue. Some methods for determination pesticide in tea. Traditional method: Quantitative analysis method (Ministry of Agriculture and Rural Development (2013).
Gas chromatography - mass spectrometry GC-MS. Structure of GC-MS system. MATERIALS, EQUIPMENT AND METHODS. Chemical and Equipment.
Preparation of sample and standard. Conditions to run the machine GC/MS. Sample injection order. Evaluation of this method.
RESULTS AND DISCUSSION. Limit of detection and limit of quantification. 40 iii LIST OF TABLES Table 3.1a: Concentration and spiked samples 10ppm (µl) to prepare the sample as a calibration curve .1b: Concentration and spiked samples 10ppm (µl), 2ppm (µl) to prepare for tea sample .1a: Limit of Detection and Quantification .1b: The result of reliability evaluation of LOD value .2: The result of concentration, peak area and the correlation coefficient of linear value .3: The result of the repeatability and the recovery .4: The result of the reproducibility. 38 iv LIST OF FIGURES Figure 3.2: GC-MS equipment .1a: Chromatography of Chlorpyrifos .1b: Calibration curve of Chropyrifos.2a: Chromatography of α-endosulfan .2b: Calibration curve of α-endosulfan .3a: Chromatography of Bifenthrin .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 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 1 they are also a serious source of pollution.
The health of consumers needs to be at the forefront, so there must be measures to reduce the excess of plant protection drugs in food products in general and tea products in particular. At the same time must control the amount of unsafe tea in the country and export. Because of economy, they control with high concentration of pesticide to kill/prevent insects. Even spraying one or two days they harvest leaves tea.
This bring harmful to our health. There are many methods to determine pesticide in vegetables or tea such as traditional methods, QUECHERS method, etc. The limitation of all these methods could not determine very low concentration of pestcides. Therefore, in this study, I propose the subject “Study on a highly sensitive method for determination of pesticide residues in tea by gas spectrometry (GC/MS)” because 3 substances of type Chlorpytifos, α- Endosulfan, Bifenthrin are three of the banned substances of the Ministry of Health [1].
This is because it will bring great benefits to farmers in terms of knowledge as well as economy, prevent signs of mistakes and offer effective and highly applicable methods food toxin analysis. In fact, there are now scientists who have methods of analysis on each crop but because of the regional characteristics as well as the variety and care of different types, the specificity of each method when apply on specific conditions is not high. Research’s objective 2 The objective of my research to evaluate a sensitive and accurate method based on: limit of detection (LOD), limit of quantification (LOQ), linearity, repeatability (Sr), recovery (%R), and reproducibility. Research question Why choose gas spectrometry (GC/MS) method to analyze pesticide residues in tea? How to confirm validity of the method? 1.Limitations Due to constraints of time and sample responsiveness, the sample size is limited.
So, certain factors could not be studied in depth. 3 PART II DOCUMENT REVIEW 2. Introduction about tea 2. Growth of tea The product of my optimal method research is tea.
The tea tree, Camellia sinensis, is a plant whose leaves and buds are used to produce tea. The name sinensis means "Chinese" in Latin. Old scientific nomenclatures include Thea bohea and Thea viridis. The growth cycle of tea tree consists of three main stages: The first is the young tree stage, the tea plants from planting to maturity need time from 3 to 4 years.
After that, there is a big tea period, which lasts from 20 to 30 years depending on the variety, soil and climate of each region, this is the period of tea with the highest productivity. At this stage, old tea trees, few buds, giving low productivity, more fruit, to overcome need to rejuvenate young trees, if done well, the tea tree can prolong life for about 5 years. Nomally, when harvesting tea, in the spring crop can be harvested 2 times. Summer and autumn are suitable for the plants to grow therefore they can be harvested once a month.
By winter, the plants are hard to grow, so they can only be harvested once every 3 months [2]. The chemistry composition of tea Chemistry compounds of tea are not simple. There are thousand chemical components contain in tea leaves/buds. When tea leaves are processed, the chemical compounds within them break down, form complexes with one another 4 and form new compounds.
Here are some basic chemical components of tea leaves such as: Polyphenols, Amino Acids, Enzymes, Pigments, Carbohydrates, Methylxanthines, Minerals, Volatile. Benefits of tea Tea is known as one of the healthiest beverages in the world. It’s loaded with antioxidants that have many health benefits. Drinking tea can improve and maintain health because it contains antioxidants.
In addition, tea also helps improve memory, blood pressure is kept stable, blood sugar levels are adjusted, and weight loss. In addition, tea also helps to keep your liver healthy, restore health, prevent disease and have a healthy skin. Especially drinking tea can prevent cardiovascular diseases and reduce the likelihood of stroke [5]. Plant protection drugs 2.
Important roles of plant protection drugs Pesticides means the common name for chemical products used in agriculture and forestry for the purpose of preventing, preventing and eliminating objects harmful to plants, agro-forestry products or for regulating, Stimulating growth for plants from field to storage [6]. The benefits that plant protection drugs bring to farmers are not small, however, tea growers aim to increase tea production, eliminate pests and diseases that damage crops, so they are increasingly using a large number of the chemical plant protection drug is toxic due to the large market demand, coupled with the increasing price of the finished tea.