(Luận văn thạc sĩ) study on a highly sensitive method for analyzing carbaryl residues in white radish by liquid chromatography tandem mass spectrometry

THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY TRAN THI YEN STUDY ON A HIGHLY SENSITIVE METHOD FOR ANALYZING CARBARYL RESIDUES IN WHITE RADISH BY LIQUID CHROMATOGRAPHY TANDEM MASS SPECTROMETRY (LC-MS /MS) BACHELOR THESIS Study Mode: Full-time Major: Food technology Faculty: Advanced Education Program Office Batch: 2016-2020 Thai Nguyen, 2020 ii ACKNOWLEDGEMENT This work would not have been possible without the support of Thai Nguyen university of Agriculture and Forestry, advanced education program office, lecturers of food technology and biotechnology faculty for their sincere guidance I received to improve my practical as well as laboratory skills First of all, I would especially like to thank Dr Vu Thi Hanh as my teacher and mentor, She had supported to me by showing different method of information collection about the study She helped all time when we needed and she gave right direction toward completion of project Second, I would like to thanks to to Mr Nguyen Xuan Thanh as a person in charge of Laboratory and all members of The center for Technical Services and Professional Training in Agroforestry –Fishery Quality – Thai Nguyen Each member in lab has provided me extensive material and professional guidance and taught me a great deal about both scientific research and life in general Finally, thanks to my parent and my friends, who provide unending inspiration For giving me encouragement, enthusiasm and invaluable assistance Sincerely, Tran Thi Yen PART I INTRODUCTION 1.1 Research rationale As we know that, Radish is one of agricultural products that bring a lot of nutritional value, providing foods, medicine for people etc Currently, there are two main types of Radish that used commonly which are white and red Radish In Vietnam, Radish is also used to treat coughs, sore throats, acne, water supply, digestive aid [1] Radish brings a lot of economic value as well as utility to people, Commented [A1]: 15/3/2016 ngon vị thuốc từ củ cải /vfa.gov.vn/ so the demand for product quality has to be increasingly raised In order to meet that demand, exporters will introduce measures such as intensive crop enhancement, seed improvement and one of the indispensable measures is used plant protection drugs Plant protection drugs are considered to be an effective weapon of human in preventing pests and protecting plants[2] Besides the advantages of protecting, increasing crop yields, pesticides also cause many other harmful effects such as environmental pollution, poisoning to humans and cattle, increasing production costs, and most is leaving residues in agricultural products that affect the quality of agricultural products and consumer health From the benefits that radish brings and to ensure the health and safety for consumers We propose a project: “Study on a highly sensitive method for analyzing Carbaryl residues in white Radish by Liquid Chromatography tandem Mass Spectrometry (LC-MS /MS)” 1.2 Research’s objective The objective for this study is evaluate the sensitive and accurate method based on: Linearity, Repeatability, Recovery, Reproducibility, Limit of detection (LOD), Limit of quantification (LOQ) 1.3 Research question - Why choose Liquid Chromatography tandem mass spectrometry method to analyze pesticide residues in white radish? - How to confirm validity of the method? Commented [A2]: Sở tài nguyên môi trường Vĩnh Phúc (2008) Thuốc bảo vệ thực vật tác động chúng 1.4 Limitations Due to constraints of time and sample responsiveness, the sample size is limited So, certain factors could not be studied in depth PART II LITERATURE REVIEW 2.1 Radishes Radish (scientific name: Raphanus sativus L) is an annual vegetable belonging to the family Cruciferae, and is a traditionally important vegetable in many countries The enlarged root and hypocotyl of radish are consumed mainly as a salted vegetable, and also eaten fresh as grated radish, garnish and salad The young leaves and seedlings known as ‘kaiware’ are also eaten [16] Classified by scientific name as follows: Plantae Angiosperms, Magnoliopsida, Brassicales, Commented [A3]: S.K Roy, A.K Chakrabarti, in Encyclopedia of Food Sciences and Nutrition (Second Edition), 2003 Brassicaceae, Raphanus, R sativus Currently, Radish is grown and used around the world has spicy taste, tubers up to 40cm long, leaves clustered in the ground Radish is a year-round vegetable that can be harvested after 45-55 days of cultivation [17] Radish is a common vegetable in many regions, can be combined with other foods to make delicious Commented [A4]: Seaman, Abby (2013-11-13) "Turnips and Radishes" Integrated crop and pest management guidelines for commercial vegetable production Retrieved 2020-05-20 food According to the Hai Thuong book: "Radish has a sweet taste, slightly bitter, non-toxic, relieved sputum, destroy stasis pine except dysentery"[1] 2.1.2 Chemical composition and nutritional value According to modern medicine, in 100g of radish contain 1.4g protid, 3.7g glucide, 1.5g cellulose, 40 mg calcium, 41 mg phosphorus; 1.1 mg of iron; 0.06 mg of vitamin B1, 0.06 mg of vitamin B2, 0.5 mg of vitamin PP, 30 mg of vitamin C Table 2.1: Nutritional value per 100g radish Components Energy Contents 18 kcal Carbohydrates 4.1 g Sugar 2.5 g Dietary fiber 1.6 g Fat 0.1 g Protein 0.68 g Commented [A5]: 15/3/2016 ngon vị thuốc từ củ cải /vfa.gov.vn/ Components Contents Vitamins Thiamine 0.012 mg Riboflavin 0.039 mg Niacin 0.254 mg Pantothenic acid (B5) 0.165 mg Vitamin B6 0.071 mg Vitamin C 14.8 mg Minerals Calcium Iron 25 mg 0.34 mg Magnesium 10 mg Manganese 0.069 mg Phosphorus 20 mg Potassium 227 mg 2.1.3 Benefits of Radish [3] - Pain reduction Spicy taste has in Radish helped antibacterial, active tendon, effective analgesic In the winter, if you pain muscular aches or joint pains, you can take radish into cloth bag, and then cover on your pain skin - Good for liver, prevent cardiovascular disease Radish contain Betaine bioactive, supports healthy liver function When the liver is properly, fat is broken down effectively, which helps to lose weight and prevent fatigue and nausea Betaine, a nutrient found in beets, helps reduce plasma homocysteine This is a risk factor for cardiovascular disease - Good for the brain A study at Wake Forest University has shown that the high amount of nitrate in radish can increase blood flow to the brain, thereby improving mental function, enhancing brain and even protecting cells brain in many years Commented [A6]: 6/7/2016 tac dung cua cu cai - Prevent anemia The natural Vitamin B12 in Radish helps promote absorption of iron, involved in the synthesis of Hemoglobin, so the increased amount of Oxygen Hemoglobin that good for the body, prevent anemia - Good for the skin Radish leaves contain vitamins A and C, especially vitamin C content higher than other vegetables, so it helps the body prevent skin aging, prevent the formation of dark spots, keep skin white and soft Addition, we can use Radish paste to clean our face - Good for heart Radishes are a good source for Anthocyanins that keep our hearts functioning properly, reducing the risk of cardiovascular diseases Addition, Radish are high on Vitamin C, Folic acid, and Flavonoids also 2.2 Plant protection products 2.2.1 Definition Plant protection drugs are toxic compounds of natural origin or synthetic chemicals used in agriculture to prevent pests for plants and agricultural products on fields and gardens, it can be called plant protection products or pesticides [2] 2.2.2 Classification [2] Plant protection drugs can be divided into main groups: - Chlorine group: Are Chlorine derivatives of some organic compounds such as Diphenyletane, Cyclodiene, Benzene and Hexane This group includes Organic compounds that very stable in the natural environment and have a long half-life Representatives of this group are Aldrin, Dieldrin, Heptachlo, Lindan, Methoxychlor - Organophosphorus group: The most of compounds are esters, which are organic derivatives of phosphoric acid This group has a shorter half-life than organic chlorine and more widely for used It affects the nerves of insects by preventing formation of Cholinestaza Enzyme, which causes the nerve to function Commented [A7]: Sở tài nguyên môi trường tỉnh vĩnh phúc (2008 )thuốc bảo vệ thực vật tác động chúng poorly, weakening muscles, causing dizziness and death This group includes some compounds such as Parathion, Malathion, Diclovos, Clopyrifos - Carbamates group: Organic derivatives of Carbamic acid, including less stable chemicals in the natural environment, but also highly toxic to humans and animals When we used, they act directly on the Enzyme Cholinestraza of the nervous system and have toxic quite the same Organophosphate group mechanism Representing for this group as Carbofuran, Carbaryl, Carbosulfan, Isoprocarb, Methomyl, etc - Pyrethroids: These are natural-derived insecticides, mixtures of different esters with complex structures separated from flowers of certain daisy varieties Representatives of this group include Cypermethrin, Permethrin, Fenvalarate, Deltamethrin, etc In addition, there are some other groups such as: Inorganic insecticides, biological insecticides derived from Bacteria, Fungi, Viruses (Fungicides, Bacteria ), Inorganic compounds (compounds of Copper, Mercury) 2.2.3 List of pesticides allowed to be used and banned in Vietnam.[4] According to Circular No 10/2019/TT Ministry of Agriculture and Rural Development about promulgating the list of pesticides allowed to be used and banned in Vietnam Commented [A8]: Theo thông tư số 10/2019/TT BNNPTNT ban hành danh mục thuốc BVTV phép sử dụng, cấm sử dụng Việt Nam Table 2.2: List number of common name and trade name for pesticides allowed to be used and banned in Vietnam Type of pesticides Number of Common name Number of Trade name Drugs used in agriculture Pesticides 850 1757 Fungicide 563 1191 Herbicide 253 659 Regicide 26 Growth regulating drugs 52 148 Insect attractant 8 Snailicide 33 153 Auxiliary substances 25 Insecticide 15 25 Preservatives Warehouse disinfectant: 10 Medicine used for golf Herbicide 1 Regulating drug 1 Seed treatment drugs Pesticides 14 Fungicides 10 11 Agricultural preservatives 1 List of pesticides banned in Vietnam Pesticides and forest 23 product preservative Fungicides Rat poison Silicide - List of pesticides allowed to be used in Vietnam 2.2.4 Effect of pesticide to health [4] Most pesticides are toxic to humans and animals at difference levels - Acute toxins: Below the lethal dose, they are not capable of causing death, gradually resolved and excreted - Chronic toxins: Ability to accumulate in the body for a long time because they are very durable, hard to be resolved and excreted Plant protection drugs can penetrate into human and animal body through many different ways, main routes: respiratory, digestive and direct contact Human exposure to pesticides may be acute or chronic poisoning, depending on the extent of the drug's effect - Acute intoxication: According to health experts, when poisoning in acute form, patients will have noticeable symptoms such as vomiting, headache, dizziness, sweating if heavier than substance toxicity will be metabolized through the liver, causing neurological disorders, insomnia, poor memory, blurred vision, hearing loss, body weakness, in women prone to miscarriage, premature birth, causing congenital malformations in a child, cancer fatigue, skin itching, headache, hoarseness, nausea, dizziness, dizziness, insomnia, increased salivation, watery eyes, if serious can lead to death - Chronic poisoning: Stimulates cancer cells to grow, cause birth defects, deformities, impaired memory and concentration, serious weakness, affecting the nervous system and brain The Poison Control Center at Bach Mai Hospital also points to signs of pesticide poisoning manifested in the digestive tract such as nausea, intense diarrhea neurological manifestations such as drowsiness, coma, convulsions, muscle paralysis, even hypotension, respiratory failure, and this is the direct cause of death in plant protection drug poisoning In addition, people may urinary problems, cholinergic syndrome has seen in the poisoning of organic phosphorus pesticides, carbamates With this syndrome, people or children will vomit, complain of shortness of breath, chest pain, sweat, body tremor or seizures 24 - Dilute stock standard solution (10 ppm): Combine 0.1 ml of stock standard into a 10ml volumetric flask Add ACN up to the mark, store in freezer, solution can storage for year - Working standard solution (1ppm) Take 1ml of 10ppm standard solution and dilute to volume with ACN in a 10ml volumetric flask The solution can store at to °C and stable for about months - Internal standard stock solution (TPP)1000ppm Weigh 10 mg TPP into a 10ml volumetric flask Dilute by ACN up to the mark Store in freezer, solution can storage for year - Dilute stock internal standard solution TPP (20ppm) Take 200µl of stock TPP 1000ppm and dilute to volume with ACN in a 10ml volumetric flask Shake well, keep to until cool and store in freezer, solution can be storage for year - Internal standard working solution (TPP) 2ppm Take 1µl TPP 20ppm and dilute to volume with ACN into a 10ml volumetric flask, and then shake well, keep for until cool This solution can store at to 8°C and storage about months - Prepare mobile phase solvent Channel A: 0.1% HCOOH solution in distill water: Absorb 1ml of HCOOH in a 100ml volumetric flask and add distill water, then mix and ultrasound Channel B: MeOH Quality of sufficient purity that is free of interfering compounds in LC-MS/MS prepared in mobile phase solution 3.5.2 Evaluate the sensitive and accurate of method [15] * Linearity - Determine the linear range by survey different concentrations Determine the linearity and trueness, the experiments are carried out on a series of standard solutions prepared on the blank sample matrix Commented [A25]: VIỆN KIỂM NGHIỆM AN TOÀN VỆ SINH THỰC PHẨM QUỐC GIA THẨM ĐỊNH PHƯƠNG PHÁP TRONG PHÂN TÍCH HĨA HỌC VÀ VI SINH VẬT DS Trần cao sơn 25 - Calculating the standard curve by the first regression line ensures that the linearity of the regression line not less than 0.99 Table 3.1: Concentration of the calibration curve Carbaryl (µg/kg) 20 60 100 200 300 TPP (µl) 100 100 100 100 100 1:9ACN/H2O 880 840 800 700 600 * Repeatability Repeated analysis of 10 spiked samples on white radish samples background at concentrations of 100μg/kg; 200µg/kg; 300µg/kg; 30µg/kg After obtained the result, calculate the standard deviation (s ) Using the formula: s : Repeatability standard deviation x : The result obtained on the i sample x: Average value of the test results, x = Σxi/n n: Number of testing samples Table 3.2: Maximum relative Standard deviation for repeatability depend on concentration range (AOAC) [15, 26] Analyte ratio Unit CV% -4 10 10-5 10-6 100 ppm 10 ppm ppm 5.3 7.3 11 10-7 10-8 100 ppb 10 ppb 15 21 10-9 ppb 30 Commented [A26]: AOAC Official Method 2007.01 Pesticide Residues in Foods by Acetonitrile Extraction and Partitioning with Magnesium Sulfate 26 * Recovery Arranging experiments at concentrations of 30µg/kg, 100µg/kg; 200µg/kg; 300µg/kg for radish samples Carried out this experiment for 10 times at each concentration above on the same test In case if using spike sample, must be test the "blank sample" (Unspike - a sample used as a spike but without add standard solution), parallel with the spike sample The result is subtracted from average blank sample value Calculate the recovery from the results obtained, using the formula: Rm = X / X Spike Rm: Recovery average X: The average value of the test results X = Σxi-xuns/n xuns: Average value of unspike samples XSpike: The concentration of spike samples Table 3.3: Recovery that accept at different concentrations (AOAC) [15, 26] n Analyzed ratio Unit Recovery [%] 10-4 100 ppm 90-107 10-5 10 ppm 80-110 10-6 ppm 80-110 10-7 100 ppb 80-110 10-8 10 ppb 60-115 10-9 ppb 40-120 * Reproducibility At least two members participated Each people analyzed 10 times spike samples on a blank samples background at the same concentration, on the same or different days Then calculate the repeatability standard deviation between two people Calculate the standard deviation of reproducibility: 27  (ai − bi ) sR = 2k - ai, bi are the i measured value of two members - k is the number of repetitions after eliminating the values of large deviations Table 3.4: Maximum relative standard deviation for reproducibility follow each concentration range (AOAC) [15, 26] Analyzed ratio Unit CV% 10 -4 100 ppm 8.0 10 -5 10 ppm 11.2 10 -6 ppm 15.9 10 -7 100 ppb 22.4 10-8 10 ppb 31.7 10-9 ppb 44.8 * Limit of detection (LOD) and Limit of quantification (LOQ) The calibration curve construction was carried out on a blank basis in the range of Carbaryl concentration of 10-400 (µg/kg) with 100µl TPP of 2ppm concentration The equation for the calibration curve is expressed as y = ax + b LOD and LOQ were calculated by repeated analysis of 5-10 times spike samples at low concentrations and calculated by the formula: LOD = × SD and LOQ = 10 × SD Where SD is the standard deviation when analyzing standardized samples at low concentrations when obtain the signal to noise ratio (S/N ≥3) S is height of signal; N is noise of sample matrix (it can be seen in figure 3.1) 28 Figure 3.1: Determine LOD base on S/N ratio 3.5.3 LC-MS/MS analysis Chromatography separation was performed with column Phenomenex C (3µm pore size, x 150mm) and protection column of the same type Linear gradient elution by Channel A contains 0.1% formic acid in distilled water, channel B is MeOH in 18 at 0.4ml/min was performed at 30ºC An injection volume of 10µl was used An infusion experiment was performed for Carbaryl to optimize the transition conditions for an MRM analysis in the electrospray ionization (ESI) positive ionization mode The condition MRM-MS measurements in the experiment for optimizing the LC separation as follows: drying gas (N2), drying temperature 450ºC and 0,4ml/min gas flow Sample inject were follow: Inject standard solutions, blank samples, and then control samples 29 PART RESULT AND DISCUSTION 4.1 Optimize the conditions for LC-MS/MS Table 4.1: Optimization of the mobile phase composition in gradient elution reversed-phase HPLC Time (Min) 0.50 5.00 6.00 7.00 12.00 14.30 Flow rate (ml/min) 0.4 0.4 0.4 0.4 0.4 0.4 0.4 %A %B 70 70 30 15 5 30 30 70 85 95 95 95 Maximum pressure (PSi) 50 50 50 50 50 50 50 After optimization of the mobile phase composition in gradient elution reversedphase HPLC, the result shown in table 4.1, Chromatographic separasion was performed in phenomenex C18 column (3µm pore size, 2mm x 150mm) Linear gradient elution by 0-100% MeOH containing 0.1% Fomic acid in 18 at 0.4 ml/min was perform at 30ºC with injection volume is 10µl Table 4.2: Optimal MRM-MS/MS conversion conditions for Carbaryl analysis Analyte Mother Daugter peak (m/z) peak (m/z) Carbaryl 201.1 145.1 Retention time (min) 3.49 127.1 TPP 327.1 159.1 3.82 After infusion to optimise MS/MS conditions, table 4.2 shown that Carbaryl gives daugters peak having hight intensity (145.1m/z and 127.1m/z ) and TPP 30 was ionized 159.1(m/z) Figure 4.1 was demonstrated that Carbaryl and TPP were run out at 3.5 min, 3.82 respectively Therefor Carbaryl was ionized successfully Figure 4.1: Standard peak of Carbaryl and TPP in chromatography analysis 4.2 Linearity Table 4.3 Peak area results were obtained in carbaryl analysis Analyte conc (µg/kg) IS conc (µl) Analyte peak area e IS peak area (e ) Ratio analyte peak/IS peak 20 100 1.87 2.90 0.65 60 100 4.93 2.64 1.87 100 100 8.69 2.79 3.1 200 100 15.6 2.74 5.7 300 100 22.6 2.66 8.5 Standard calibration curve was performed by blank sample matrix (sample does not contain pesticide need to analysis) Prepare standard of Carbaryl at 20300µg/kg concentration On this method, TPP will be used as internal standard TPP have chemical and physical properties that relatively similar with Carbaryl Observed in Figure 4.2, the linear correlation of Carbaryl between 20 and 300µg/kg with a coefficient of correlation (r) = 0.999 Analyte peak/ IS peak 31 y = 0.0277x + 0.2001 R² = 0.9994 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 Analyte conc/IS conc Figure 4.2: Calibration curves of Carbaryl 4.3 Limit of detection and limit of quantification Determine the LOD and LOQ procedure by add standard at low concentration into the samples does not contain the chemical that need to analysis On this experiment, we added standard at 50µg/kg concentration, and then parameter the signal to noise ratio (S/N), if S/N ≥ 3, calculate the standard deviation to determine the LOD and LOQ Considering the result on table showed that LOD is 9.81µg/kg and LOQ is 32.71µg/kg To confirm the LOD and LOQ value for this method, we analyzed 10 times reduplicate on blank samples added standard at LOD threshold (10 ppb) See the results on table 3, it can be seen that Carbaryl gives a mother peak and daughter peaks that have S/N ≥ (The results similar with AOAC at survey concentration) So that, can be confirmed that LOD is 10 ppb are acceptable for this method 32 Table 4.4: Limit of Detection and Quantification for Carbaryl analysis n=10 Signal to noise 50µg/kg ratio (S/N) 100.6 48.50 66.5 49.50 93.1 47.90 87.5 48.80 121.5 52.50 197 51.60 166.2 45.50 155.6 56.60 212.1 51.10 10 163.2 46.20 SD 3,27 CV (%) 6,57 LOD (µg/kg) 9,81 LOQ (µg/kg) 32,71 Table 4.5: The result of reliability evaluation of LOD value in Carbaryl analysis at 10ppb concentration (n) Samples S/N ratio S/N ≥ 3 10 498.7 326 443.2 437.6 367.3 236.8 685.7 366.7 515 546.9 ≥3 ≥3 ≥3 ≥3 ≥3 ≥3 ≥3 ≥3 ≥3 ≥3 33 ion, m/z 202>127.1 202>145.1 4.4 Recovery and repeatability Under the optimal LC-MS/MS conditions in table 4.2, we performed the experiment at difference concentration (30µg/kg, 100µg/kg, 200µg/kg, 300µg/kg) Each experiments performed for 10 times on the same samples does not contain the chemical that need to analysis The recovery (R%) was determined by the reality result of Carbaryl after analysis and initial concentration was added Considering the result in table 4.6 that the recovery of Carbaryl at each concentration were higher than 100% In addition, the coefficient of variance bigger than 10 From the result above, it clear that the optimal LC-MS/MS conditions were accurately and suitable for this method Table 4.6: Recovery and repeatability in Carbaryl analyze Samples 30 µg/kg 10 Average SD R% CV% 27,8 30,15 32,1 31,4 30,45 33,0 32,05 31,95 32,3 29,25 31,05 1,61 103,4 5,19 100µg/kg 200µg/kg 300µg/kg 105 110 105 102 109 105 110 105 103 109 106,3 2,95 106,30 2,77 203 195 212 203 209 200 212 203 195 200 203,56 6,18 101,60 3,04 305 307 312 307 309 300 303 307 310 311 307,10 3,70 102,37 1,20 4.5 Reproducibility In this experiment we analyzed at concentration of 30µg/kg on blank background matrix samples Each people performed this experiment repeat 10 times, compare the results between two members and then calculated the CV and 34 SD for the method Observation the results in table 4, it’s conclude that the CV= 4.28 % and SD = 1.32 (the result are similar with AOAC at the same concentration) [27] Table 4.7: The result obtained from analysis Carbaryl at concentration of 30 µg/kg between members n Member Member 27,8 30,94 30,15 32,35 32,1 30,4 31,4 30,4 30,45 29,2 33,01 29,65 32,05 31,05 31,96 31,65 32,3 30,25 10 29,25 29,7 Average 31,045 30,56 CV(%) 4,27 SD 1,32 35 PART V CONCLUSION From the results above, it shown that the method for determined the active substance Carbaryl by liquid chromatography tandem mass spectrometry LC-MS/ MS with the following results: Limit of detection for this method is 10µg/kg, Limits of quantitation were demonstrated to be ≥30µg/kg The average recoveries of pesticide were in the range of 100 –110% with linear regression coefficient r ≥0.99 and the variation is less than 10% From the above analysis results, it can be confirmed that method is fast, sensitive, accurate and reliable for analyzing the active substance Carbaryl in white radish 36 REFEREENCES I Vietnamese references 15/3/2016 medicinal delicious dish from radish Vinh Phuc resource base and environment (2008) Plant protection drugs and their effects 6/7/2016 the benefits of radish According to Circular No 10/2019 / TT BNNPTNT promulgating the list of pesticides allowed and banned to use in Vietnam Danchi (2006) vegetables with excess pesticides Danchi (31/07/2018) More than half of people tested were infected with pesticides in their blood Trung Kien30/4/2017 Agricultural production for export " difficulty" because of residues of plant protection drugs Dieu Thu (09/06/2016) More than 5% of the vegetables sold on the market are contaminated with banned substances Ninh Thuan Police (2009), More than two million people eat dirty vegetables 10 Nguyễn Thị Thanh Huyền 01/11/2010 The harmful effects of plant protection drugs to human health and the environment 11 Van Hai (17/01/2018) Nearly 200 children in Hanoi suffered from food poisoning 12 Robert L Metcalf “Insect Control” Encyclopedia Ullmann for Chemical industry”Wiley-VCH, Weinheim, 2002 13 The Hazard data in pesticide Carbaryl was archived on May 11, 2010, Wayback Machine 14 Circular No 50-2016 TT/BYT on Regulations on maximum limit of pesticide residues 37 15 Tran Cao Son, National Institute of Food Safety and Hygiene Evaluation of methods in chemical and microbiological analysis II English references 16 S.K Roy, A.K Chakrabarti, in Encyclopedia of Food Sciences and Nutrition (Second Edition), 2003 17 Seaman, Abby (2013-11-13) "Turnips and Radishes" Integrated crop and pest management guidelines for commercial vegetable production Retrieved 2020-05-20 18 2003 NPIC national pesticide information center 19 A World Compendium: The Pesticide Manual, 12th ed.; Tomlin, C D S., Ed.; British Crop Protection Council: Farnham, Surrey, UK, 2000; pp 67-68 20 Oct 2003, U.S Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division.Revised EFED Risk Assessment of Carbaryl in Support of the Reregistration Eligibility Decision 21 R David Jones, Ph.D., Senior Agronomist Thomas Steeger, Ph.D., Senior Biologist March 18, 2003 Revised EFED Risk Assessment of Carbaryl in Support of the Reregistration Eligibility Decision (RED) 22 Berk, Zeki (2013) "Food Process Engineering and Technology (Second Edition)" Advances in Molecular Toxicology 23 Journal of Chromatography a volume 856, Issues 1–2, 24 September 1999, Pages 3-54 24 Quechers Methodology: AOAC Method Q-sep™ Packets cat 26237 and 26238 25 Michelangelo Anastassiades, 2003 26 AOAC Official Method 2007.01 Pesticide Residues in Foods by Acetonitrile Extraction and Partitioning with Magnesium Sulfate 38 ... ensure the health and safety for consumers We propose a project: ? ?Study on a highly sensitive method for analyzing Carbaryl residues in white Radish by Liquid Chromatography tandem Mass Spectrometry. .. Therefor Carbaryl was ionized successfully Figure 4.1: Standard peak of Carbaryl and TPP in chromatography analysis 4.2 Linearity Table 4.3 Peak area results were obtained in carbaryl analysis Analyte... bonded phase chromatography In fact, bonded phase chromatography has been found to have more advantages than liquid- liquid phase chromatography for some reasons: - Stationary phase in liquid- liquid