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

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:

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

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,

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 [A1]: 15/3/2016 món ngon vị thuốc từ củ cải

/vfa.gov.vn/

Commented [A2]: Sở tài nguyên và môi trường Vĩnh Phúc

(2008) Thuốc bảo vệ thực vật và những tác động của 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,

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

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

Commented [A3]: S.K Roy, A.K Chakrabarti, in

Encyclopedia of Food Sciences and Nutrition (Second Edition), 2003

Commented [A4]: Seaman, Abby (2013-11-13) "Turnips

and Radishes" Integrated crop and pest management guidelines for commercial vegetable production Retrieved 2020-05-20

Commented [A5]: 15/3/2016 món ngon vị thuốc từ củ cải

/vfa.gov.vn/

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 4 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 và môi trường tỉnh vĩnh

phúc (2008 )thuốc bảo vệ thực vật và tác động của 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 được phép sử dụng, cấm sử dụng tại Việt Nam

Table 2.2: List number of common name and trade name for pesticides allowed

to be used and banned in Vietnam

Drugs used in agriculture

List of pesticides banned in Vietnam

Pesticides and forest

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, 3 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

2.2.5 Current situation of pesticide residues in vegetables

- Determined 790 samples of 52 units of safe vegetables business in the city,

Ho Chi Minh City Plant Protection Department detected 26 samples of pesticide

residue, accounting for 3.29% The inspection was conducted over the past 11

months Straw mushrooms Tra Vinh, celery, lettuce, broccoli (cauliflower),

amaranth, celery are kind of vegetables contain a high rate of pesticide residue

(3.94%) Including 5 green onion samples of Da Lat, 2 samples of morning glory

and choysum of Ho Chi Minh City, which over maximum residue level [5]

- 31/67 people in Hanoi were tested with blood levels of pesticides The

results were published by the Institute of Occupational Health and Environment

(Ministry of Health) when conducting random tests at a class of the Center for

Community Learning of communes and towns from 4 suburban districts of Hanoi

including Soc Son, Dong Anh, Me Linh and Hoai Duc 31 people at risk (having

pesticides stored in the blood); one person at risk (more dangerous than risk)[6]

- More than 221 types of pesticides are found in vegetables, of which nearly

half exceeds the maximum allowed or banned concentrations For the past 10 years,

countries like Australia, the US, Japan and the EU have rejected 483 Vietnamese

vegetable products worth more than US $ 1 billion, according to Dr Hong Minh,

the reason that Vietnamese agricultural products are less exported is that farmers

apply fertilizers and pesticides in excess of the permitted level Enterprises do not

implement or not follow standards such as VIETGAP, Global GAP[7]

- In recent years, the authorities took 7593 samples of vegetables and found

393 samples contaminated with banned substances, pesticide residues exceeding the

permitted limit (accounting for 5.17%) This shows that the level of violation

detection is still high, not meeting people's expectations People are not really

assured about food safety is also understandable If the manufacturer does not

comply with the principles of the use of plant protection products, there is a risk of

unsafe products [8]

Commented [A9]: Danchi (2006) rau xạch thừa thuốc trừ

sâu

Commented [A10]: Danchi (31/07/2018) Quá nửa số

người xét nghiệm bị nhiễm thuốc trừ sâu trong máu

Commented [A11]: Trung kiên 30/4/2017 Nông sản xuất

khẩu "gặp khó" vì tồn dư thuốc bảo vệ thực vật

Commented [A12]: Diệu thu (09/06/2016) Hơn 5% lượng

rau bán trên thị trường nhiễm chất cấm

- In Ho Chi Minh City, in the first six months of 2009, more than 2,200

samples of vegetables and fruits were tested in three wholesale markets (Binh Dien,

Hoc Mon and Thu Duc) with 50 positive samples (2.4%), 1.3% higher than the

same period in 2008 In Binh Duong, analyzing nearly 310 samples of vegetables

taken from markets, production areas and collective kitchens in the first eight

months of 2009, nearly 80 samples had residues of plant protection drugs[9]

2.2.6 Food poisoning situation due to pesticides

- According to a survey of the Department of Preventive Medicine and

Environment of Vietnam, more than 5000 cases of toxic chemical pesticides are

hospitalized every year and more than 300 deaths The harmful effects of plant

protection drugs on the human body and the surrounding environment occur when

the drug is used not in compliance with the prescribed standards [10]

- On 14/11, Xuan Non Kindergarten's collective kitchen organized cooking

for 796 lunches and snacks at 14:00 pm on the same day Lunch menu includes:

Sausage, Beef with Wine Sauce, Rancid street, Duong Chau fried rice, Mixed

boiled vegetables, orange juice Afternoon meal includes yogurt, cakes After

finished lunch there were 3 teachers and nearly 200 students were admitted to Dong

Anh General Hospital and North Thang Long Hospital with the symptoms of

abdominal pain, vomiting, diarrhea, headache and fever [11]

2.3 Carbaryl

Carbaryl (1-naphthyl methylcarbamate) is a chemical in the carbamate group

used primarily as a pesticide It is a white crystalline solid commonly sold under the

brand name Sevin, a trademark of the Bayer Company Union carbide discovered

carbaryl and introduced it to the market in 1958 Bayer purchased Aventis

CropScience in 2002, a company that includes the union carbide pesticide activities

It remains the third most widely used insecticide in the United States for home

gardens, commercial agriculture and forest protection and rangeland About 11

million kg were applied in U.S agricultural crops in 1976

Commented [A13]: Công An Ninh Thuận ( 2009), Hơn hai

triệu người ăn rau bẩn

Commented [A14]: Nguyễn Thị Thanh Huyền 01/11/2010

Tác hại của thuốc hóa chất bảo vệ thực vật đối với sức khỏe con người và môi trường

Carbaryl have chemical formula is C12H11NO2, molar mass is 201.225

g·mol−1, melting point at 142 °C (288 °F; 415 K), the solubility in water very low

(0.01% at 20°C)

Figure 2.1 structure formula of Carbaryl

Carbaryl is the active ingredient in Carylderm shampoos used to combat

head lice until the infestation is removed [12] Although approved for over 100

crops in the US, Carbaryl is illegal in the UK, Austria, Denmark, Sweden, Iran,

Germany and Angola [13]

The Acceptable Daily Intake for carbaryl (ADI) is 0.008mg/kg of body

weight For mice, the average lethal dose LD50 = 250-850mg/kg, the average lethal

concentration LC50 = 0.005 - 0.023mg/kg The Maximum Residue Level content in

beets is 0.1mg/kg

- Application of carbaryl[19]

• Carbaryl is used to control a wide range of pests, including beetles,

cockroaches, ants, ticks and mosquitoes

• Carbaryl products can be made in the form of dust, absorbent powders,

liquid concentrates, granules

• Carbaryl products are used on fruits, vegetables, rangeland, lawns,

ornamental plants, trees, and building foundations

- Effect of carbaryl to health

• Early symptoms associated with Carbaryl exposure may include headache,

muscle weakness, nausea, stomach cramps, sweating, and restlessness The effects

of carbaryl on human health and the environment depend on the amount of Carbaryl

Commented [A15]: Robert L Metcalf “côn trùng Control”

trong Bách khoa toàn thư Ullmann của Hóa học công nghiệp”Wiley-VCH, Weinheim, 2002 doi : 10,1002 / 14356007.a14_263

Commented [A16]: Dữ liệu nguy hiểm về thuốc trừ sâu

Carbaryl được lưu trữ ngày 11 tháng 5 năm 2010, tại Wayback Machine

Commented [A17]: 2003 NPIC national pesticide inf

center

present and the length and frequency of exposure The reaction also depends on the

health of each person or certain environmental factors

Greater exposure to Carbaryl can lead to mydriasis, tearing, excessive

salivation, runny nose, vomiting, diarrhea, muscle twitching, and coordination

problems Severe poisoning can lead to convulsions, coma and death

• Carbaryl is practically non-toxic to birds such as ducks, quails, geese and

pheasants [20]

• Carbaryl ranges from toxic to extremely toxic to some fish [20]

Carbaryl is highly toxic to beneficial insects and bees are likely to be

impacted if they are located in the application site Bee kill incidents have been

reported; however, except for a single use of carbaryl on asparagus, a specific use

could not be implicated While concern has been raised regarding the use of

carbaryl to thin fruit in orchards, a field study of this use indicated that carbaryl did

not impact bee mortality and/or behavior [21]

- Maximum residue limit of carbaryl [15]

- Maximum Residue Level - MRL is the maximum content of a pesticide

residue in a food (unit: mg/kg of food)

- Acceptable Daily Intake – ADI is the daily intake of a chemical throughout

life without harm to human health (unit: mg/kg body weight)

Table 2.3: MRL and ADI of Carbaryl in some vegetables

Commented [A18]: A World Compendium: The Pesticide

Manual, 12th ed.; Tomlin, C D S., Ed.; British Crop Protection Council: Farnham, Surrey, UK, 2000; pp 67-68

Commented [A19]: 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 (RED)

http://cascade.epa.gov/RightSite/getcontent/Tempfile.pdf?D MW_OBJECTID=090007d480153434&DMW_FORMAT=p

df (accessed Oct 2003)

Commented [A20]: 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)

Commented [A21]: Theo thông tư số 50-2016 TT/BYT

về Quy định giới hạn tối đa dư lượng thuốc bảo vệ thực vật trong thực phẩm

2.4 Current methods for determination of Carbaryl in vegetable

2.4.1 Traditional methods

Some traditional methods are used to determine pesticide residues in fruits

and vegetables such as: Liquid–Liquid Extraction, Microwave Assisted Extraction,

Solid Phase Extraction, Supercritical Extraction Most of which take a long time

Liquid–liquid extraction, also known like solvent extraction and

partitioning, is a method to separate compounds or metal complexes, based on their

relative solubility in two different immiscible liquids Then transfer the analyze

from one solvent to the second insoluble solvent with the first solvent, recovered the

solvent and obtained the analyze Depending on the chemical analyze, select an

appropriate solvent to avoid loss analyze Attention should be paid to factors that

affect the extraction process: solubility of the analyze in the solvent, temperature,

the other solutes In addition, selecting the right solvent will help remove some of

the impurities in the sample It is possible to use a number of auxiliary physical

agents such as mechanical shaking, super-speed agitation, ultrasonic waves, etc For

highly impurities samples, it is possible to coordinate with other cleaning processes

[22]

Solid phase extraction is a collection technique where compounds dissolved

or suspended in a liquid mixture are separated from other compounds in the mixture

according to their physical and chemical properties In analytical lab, using solid

phase extraction to concentrate and purify samples for analysis Solid phase extracts

can be used to isolate analyses of hold from a variety of matrices, including blood,

water, beverages, soil and animal tissue Although this method have cost is low,

accuracy is quite high but it Incomplete removal of the interferences and high

variability in the results observed [23]

2.4.2 QUECHERS method [24]

The QUECHERS method it means quick, easy, cheap, effective, rugged and

safe It was expanded by Michelangelo Anastassiades in the years 2001 and 2002

The first time, the methodology was developed for the analysis of veterinary drugs

Commented [A22]: Berk, Zeki (2013) "Food Process

Engineering and Technology (Second Edition)" Advances in Molecular Toxicology, 2014 ISBN 978-0-12-415923-5

Commented [A23]: Journal of Chromatography A

Volume 856, Issues 1–2, 24 September 1999, Pages 3-54

https://doi.org/10.1016/S0021-9673(99)00832-8

in animal tissues but after know its great potential in the extraction of polar and

particularly basic compounds it was also tested on pesticide residue analysis in plant

material like fruits, vegetables in currently, QUECHERS technique is the basis for

widely recognized testing methods in the world such as AOAC 2010 (2001.07), EN

15662 and is being applied in the large and modern laboratories in our country [25]

A simple, quick and cheap method to determine pesticide residues in fruits and

vegetables is introduced The procedure involves extracting an initial phase of 10 g

of the sample with 10 ml of acetonitrile, followed by a liquid-liquid partition

formed by adding 4 g of anhydrous MgSO4 plus 1 g of NaCl The removal of

residual water and cleaning is carried out simultaneously using a fast procedure

called dispersed solid phase (dispersion-SPE), in which 150 mg of anhydrous

MgSO4 and secondary amine absorbent (PSA) 25 mg is simply mixed with 1 ml of

acetonitrile extract Dispersion-SPE with PSA effectively eliminates many polar

matrix components, such as organic acids, certain polar pigments and sugars, to

some degree from food extracts Gas chromatography mass spectrometry (GC/MS)

is then used for quantitative analysis and confirmation of GC-amenable pesticides

A recovery of 85 to 101% (mainly> 95%) and repeatability <5% were achieved for

a range of enhanced pesticides, including basic and polar compounds such as

Methamidophos, Acephate, Omethoate, Imazalil and Thiabendazole Using this

method, a single chemist can prepare a batch of 6 previously shredded samples in

<30 minutes with about 1 dollar (US) of material per sample

2.5 Liquid chromatography tandem mass spectrometry (LC-MS/MS)

Mass spectrometry liquid chromatography (LC-MS) is an analytical chemical

technique that combines the physical separation of liquid chromatography (or

HPLC) with the ability to analyze the mass of mass spectrometry (MS)

Chromatography combined - MS systems are popular in chemical analysis

because the individual capabilities of each technique are enhanced synergistically

Although this method is newly introduced, it is widely applied to analysis of

pesticides, 23 especially Carbamate group The method has many advantages such

Commented [A24]: Michelangelo Anastassiades, 2003)

as high selectivity, low detection limit, fast analysis time, and high efficiency Simultaneous quantification of substances with the same retention time

solvents must be pure solvents used for HPLC All reagents used for sample preparation and buffering phase must be of analytical reagent

- Pump

Pump is an important part of the HPLC system High pressure pumps are used

to push the solvent through the stationary phase The smaller the particle size of the stationary phase, the higher the pump pressure can withstand The requirement for HPLC pumps is to create a constant, stable mobile phase current Current HPLC pumps can offer flow rates of 0.1-10ml/min with fluctuations not more than 1%, maximum pressure up to 5000psi

- Injector

There are 2 ways to get a sample into the column: by manual injection and autosamper Programize from sample injection volume, sample change time, sample entry wash time, sample injection temperature, sample injection pressure

- HPLC column

Figure 2.4: LC columns 50 × 2 mm

Columns are usually made of polished stainless steel, are between 50 and 300

mm long and have an internal diameter of between 2 and 5mm They are commonly filled with a stationary phase with a particle size of 3–10µm

- Detector

The detector for HPLC are very diverse, common types of detector such as UV-VIS, fluorescence, thermal conductivity, mass-spectrometric detector Retention time and pick area are important measurement parameters for chromatography

- Data Collection Devices

The Data Collection Devices has the ability to draw graphs, determine retention time, peak area, save determination methods, and can use the recorder to control and make program for chromatographic process

- Static phase make chemically bonded to substrate - 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 chromatographic systems that easily to dissolved by the mobile phase, so it is easy to lose the mobile phase during analysis process and cause contamination for analyze

- Due to the stationary phase of liquid-liquid chromatography that dissolves easily in the mobile phase So, cannot be applied solvent gradient elution method Therefore, it interested in this type of bonded phase chromatography and most

of the column types used that have structure as: Surface of silica - SiO2 particles (these particles have a diameter of 3.5 or 10µm) have been alkylated, not polarized, the most common type is –C18H37

2.5.2 Mass spectrometry detector

Mass spectrometry is a method of studying substances by measuring and analyzing the exact molecular weight of such substances based on the movement of atomic or molecular ions in a given electric or magnetic field The mass and area ratio (m/z) has a great influence on this movement of ions If know the ion area, it is easy to determine its mass