Sàn giao dịch phế liệu online
Mô hình kinh tế tuần hoàn

Since 2007

Phân loại thuốc BVTV

  • Thread starter minhngu1988
  • Ngày gửi
M

minhngu1988

Guest
An toàn hóa chất | an toàn lao động | Sự cố tràn dầu | Bộ ứng cứu tràn đổ 25L
Chào tất cả ace! :005:
Số là em đang làm cái luận văn tốt nghiệp, đề tài "Khảo sát hiện trạng sử dụng nông dược trên lúa vụ Đông Xuân"
Em đi pv các pác nông dân rồi (100 bác), giờ về thì GVHD kêu em phân loại thuốc BVTV để chạy SPSS, em phỏng vấn mấy bác nông dân chỉ được những cái tên như: trừ sâu: Abathai, Abagrow...., trừ cỏ có: sofix, topshot...., trừ bệnh thì Anvil, Annongvil...
Kết quả là em chỉ thu được những cái tên thương phẩm, nếu chịu khó tra danh mục thì chỉ được hoạt chất là cùng :30::30:. Nhưng GVHD của em "khuyến khích" :gunsmilie: em phân loại theo gốc Clo hữu cơ, Lân hữu cơ, Cacbamate, Cúc tổng hợp...
Em ko có cách nào để tiếp tục khâu thống kê hết.
Có ai có tài liệu hay thông tin gì về vấn đê thì xin chỉ dạy.
Em xin chân thành cảm ơn. !!!!!!!!!!
 

huunam

Cây công nghiệp
Tham gia
30/8/09
Bài viết
379
Cảm xúc
8
An toàn hóa chất | an toàn lao động | Sự cố tràn dầu | Bộ ứng cứu tràn đổ 25L
Chào tất cả ace! :005:
Số là em đang làm cái luận văn tốt nghiệp, đề tài "Khảo sát hiện trạng sử dụng nông dược trên lúa vụ Đông Xuân"
Em đi pv các pác nông dân rồi (100 bác), giờ về thì GVHD kêu em phân loại thuốc BVTV để chạy SPSS, em phỏng vấn mấy bác nông dân chỉ được những cái tên như: trừ sâu: Abathai, Abagrow...., trừ cỏ có: sofix, topshot...., trừ bệnh thì Anvil, Annongvil...
Kết quả là em chỉ thu được những cái tên thương phẩm, nếu chịu khó tra danh mục thì chỉ được hoạt chất là cùng :30::30:. Nhưng GVHD của em "khuyến khích" :gunsmilie: em phân loại theo gốc Clo hữu cơ, Lân hữu cơ, Cacbamate, Cúc tổng hợp...
Em ko có cách nào để tiếp tục khâu thống kê hết.
Có ai có tài liệu hay thông tin gì về vấn đê thì xin chỉ dạy.
Em xin chân thành cảm ơn. !!!!!!!!!!

Phân loại để làm gì vậy? Mục đích cho việc phân loại này để làm gi?,... Việc phân loại theo gốc Clo hữu cơ, lân,.. chỉ là một cách phân loại tổng hợp thống kê có thể để đánh giá,...
Nhưng luận văn của bạn chỉ dừng lại Khảo sát hiện trạng sử dụng nông dược trên lúa vụ Đông Xuân (Cho vùng nào hay khu vực nào?) đâu nhất thiết phải phân loại theo mấy thành phần này vì hàm lượng, liều lương nó đã có định sẵn. Nếu bạn muốn đánh giá tình hình hiện trạng sử dụng thuốc BVTV trên đồng ruộng thì đến khu vực đó có thể tiến hành lập phiếu khảo sát từ nông dân, đại lý, nhà phân phối, Công ty sản xuất... để từ trên cơ sở đó Chạy SPSS tổng hơp đánh giá hiện trạng sử dụng nông dược cũng như các vấn đề khác có liên quan đến, hàm lượng, tải lượng dư thừa các gốc hóa chất...
Trên cơ sở đó mà chúng ta có thể đưa ra các dự đoán phòng ngừa, năng chặn,... và đề ra các giải pháp cơ sở điển hình cho việc kiểm soát ô nhiễm đất khu vực đó.
Việc đánh giá hiện trang sử dụng thuốc BVTV cho một vùng bạn có thể liên hệ các phòng nông nghiệp,... các hợp tác xã khuyến nông, hay các marketing, họ có sẽ nắm rất rõ các chi tiêu doanh số bán trong quý,...

........
 

black_jack

Mầm xanh
Tham gia
24/11/09
Bài viết
19
Cảm xúc
0
An toàn hóa chất | an toàn lao động | Sự cố tràn dầu | Bộ ứng cứu tràn đổ 25L
mình có một ít tài liệu về phân tích thuốc bảo vệ thực vật bằng phương pháp GC bà con tham khảo và đóng góp nha

:telephone:ENDOSULFAN 213
6. ************YTICAL METHODS
The purpose of this chapter is to describe the ************ytical methods that are available for detecting,
measuring, and/or monitoring endosulfan, its metabolites, and other biomarkers of exposure and effect to
endosulfan. The intent is not to provide an exhaustive list of ************ytical methods. Rather, the intention is
to identify well-established methods that are used as the standard methods of ************ysis. Many of the
************ytical methods used for environmental samples are the methods approved by federal agencies and
organizations such as EPA and the National Institute for Occupational Safety and Health (NIOSH). Other
methods presented in this chapter are those that are approved by groups such as the Association of
Official ************ytical Chemists (AOAC) and the American Public Health Association (APHA).
Additionally, ************ytical methods are included that modify previously used methods to obtain lower
detection limits and/or to improve accuracy and precision.
6.1 BIOLOGICAL SAMPLES
Endosulfan in its pure form is a crystalline substance consisting of α- and β-isomers in the ratio of
approximately 7:3. It is an organochlorine pesticide, and ************ysis of biological and environmental
samples for endosulfan commonly results in the detection of other organochlorine pesticides and
polychlorinated biphenyls. These can interfere with the determination of endosulfan unless adequate
cleaning and separation techniques are used. Detection of low levels of endosulfan typically involves
extraction of samples with organic solvents, a clean-up step to remove lipids and other materials that may
interfere with ************ysis, high-resolution gas chromatography (HRGC) to separate endosulfan from other
compounds in the extract, and confirmation of endosulfan by electron capture detector (ECD) or mass
spectroscopy (MS). Method blanks and control samples should be used to verify method performance
and to ensure that the reagents and glassware are not introducing contaminants that might interfere with
the determination of endosulfan isomers or endosulfan sulfate.
The method of choice for the determination of α- and β-endosulfan in blood, urine, liver, kidney, brain,
and adipose tissue is gas chromatography equipped with an electron capture detector (GC/ECD)
(Coutselinis et al. 1976; Demeter and Heyndrickx 1979; Demeter et al. 1977; Le Bel and Williams 1986).
This is because GC/ECD is relatively inexpensive, simple to operate, and offers a high sensitivity for
halogens (Griffith and Blanke 1974). After fractionation of adipose tissue extracts using gel permeation
chromatography, detection limits of low-ppb (1.2 ng/g) were achieved for endosulfan and other
chlorinated pesticides using GC/ECD (Le Bel and Williams 1986).
ENDOSULFAN 214
6. ************YTICAL METHODS
A new technique has been developed to ************yze α- and β-endosulfan concentrations in human urine
(Vidal et al. 1998). Samples are mixed with a buffer solution and then passed through solid phase
extraction cartridges for ************ysis using gas chromatography-tandem mass spectrometry (GC-MS-MS).
β-Endosulfan has also been measured in hand rinsings using GC/ECD (Kazen et al. 1974). Sample
preparation involves hand rinses with hexane followed by concentration, fractionation, and clean-up with
Florisil®. Sensitivity, recovery, and precision data were not reported.
Positive identification of low-ppb (μg/L) levels of endosulfan in human blood has been achieved by GC
equipped with a microcoulometric detector (GC/MC) (Griffith and Blanke 1974). Although GC/MC is
specific and nearly as sensitive as GC/ECD for detecting endosulfan in blood, GC/MC is more difficult to
operate. Both isomers of endosulfan can be measured in blood using a method described by Guardino et
al. (1996). According to the authors, endosulfan can be recovered and measured with an approximate
limit of quantitation (LOQ) of 0.2 μg/L (sub-ppb).
GC/MS has been employed by Demeter et al. (1978) to quantitatively detect low-ppb levels of α- and
β-endosulfan in human serum, urine, and liver. This technique could not separate α- and β-isomers, and
limited sensitivity confined its use to toxicological ************ysis following exposures to high levels of
endosulfan. More recently, Le Bel and Williams (1986) and Williams et al. (1988) employed GC/MS to
confirm qualitatively the presence of α-endosulfan in adipose tissue previously ************yzed quantitatively by
GC/ECD. These studies indicate that GC/MS is not as sensitive as GC/ECD. Mariani et al. (1995) have
used GC in conjunction with negative ion chemical ionization mass spectrometry to determine alpha- and
beta-endosulfan in plasma and brain samples with limits of detection reported to be 5 ppb in each matrix.
Details of commonly used ************ytical methods for several types of biological media are presented in
Table 6-1.
6.2 ENVIRONMENTAL SAMPLES
Reliable ************ysis of endosulfan residue concentrations in environmental samples usually involves
detection of the α- and β-isomers plus endosulfan sulfate (a degradation product of endosulfan). GC/ECD
has been the most widely used ************ytical technique for determining low-ppb to parts-per-trillion (ppt)
levels of α- and β-endosulfan and endosulfan sulfate in air, water, waste water, sediment, soil, fish, and
various foods (Bennett et al. 1997; Chopra and Mahfouz 1977a; EPA 1988a, 1997a, 1997b, 1997c,
1992a; FDA 1994; Fisk 1986; Fukuhara et al. 1977; Giabbai et al. 1983; Goebel et al. 1982; Kutz et al.
ENDOSULFAN 215
6. ************YTICAL METHODS
Table 6-1. ************ytical Methods for Determining Endosulfan in Biological Samples
Sample matrix Preparation method
************ytical
method
Sample detection
limit
Percent
recovery Reference
Blood Acidification of blood sample and
extraction with ether; evaporation
of extract to dryness and
dissolution of residue in hexane
GC/ECD No data 65–68 Coutselinis et al. 1976
Blood Addition of H2SO4 to blood
sample, extraction with hexane,
acetone (9:1) and extract
concentration
GC/MC 10–20 μg/L (ppb) 50 Griffith and Blanke 1974
Blood Homogenization of sample
followed by extraction with
methanol and centrifugation;
isolation of pesticides using SPE
GC/ECD Approximately
0.2 μg/L (ppb)
No data Guardino et al. 1996
Blood (serum)
and urine
Extraction of sample with benzene
and concentration; clean-up using
HPLC
GC/MS Low/μg/L (ppb) levels 99–103%
(generally
1–14% RSD;
worst for
serum)
Demeter et al. 1978
Plasma, brain
(alpha and beta)
Brain: homogenization with
ethanol, centrifugation, phase
separation and evaporation of
ethanol and addition of internal
stardard. Plasma: extraction with
hexane and then as for brain
samples
GC/NICI MS 5 ng/mL for plasma
(ppb); 5 ng/g (ppb) for
brain; 8–31% RSD
85–93 Mariani et al. 1995
Liver, kidney, and
brain
Homogenization and addition of
hexane to tissue sample;
evaporation of extract to dryness;
dissolution of residue in hexane
GC/ECD No data 65–68 Coutselinis et al. 1976
ENDOSULFAN 216
6. ************YTICAL METHODS
Table 6-1. ************ytical Methods for Determining Endosulfan in Biological Samples (continued)
Sample matrix Preparation method
************ytical
method
Sample detection
limit
Percent
recovery Reference
Liver Addition of water to sample
followed by homogenization;
extraction with benzene, clean-up
on silica column and HPLC
GC/ECD No data No data Demeter and Heyndrickx
1979
Liver Addition of water to sample
followed by homogenization an
dextraction with benzene; cleanup
extract on HPLC
GC/MS Low μg/L (ppb) levels No data Demeter et al. 1978
Adipose tissue Addition of acetone: hexane
(15:88) to tissue followed by
homogenization; clean-up extract
on gel permeation and Florisil®
columns
GC/ECD and
GC/MS
0.0012 μg/L (ppb) 96.5 (at 0.01
μg/L)
Le Bel and Williams 1986
Hand rinsings Rinsing of hands twice with
hexane; solvent volume reduction;
fractionation and clean-up on
Florisal®
GC/ECD No data No data Kazen et al. 1974
ECD = electron capture detector; GC = gas chromatography; HPLC = high-performance liquid chromatography; MC = microcoulometric detector; MS = mass
spectrometry; NICI = negative ion chemical ionization; RSD = relative standard deviation; SPE = solid phase extraction
ENDOSULFAN 217
6. ************YTICAL METHODS
1976; Marsden et al. 1986; Mitchell 1976; Musial et al. 1976; Noroozian et al. 1987; Pokharker and
Dethe 1981; Woodrow et al. 1986; Zoun et al. 1987). Both GC and high performance liquid
chromatography (HPLC) have been used to separate endosulfan and its major metabolites endosulfan
ether, endosulfan sulfate, endosulfan lactone, and endosulfan diol (Kaur et al. 1997).
Solid phase micro extraction (SPME) is a techniques in which a silica fiber coated with a thin film of
polymer is brought into contact with an aqueous matrix where the organics in solution partition onto the
fiber. The fiber is subsequently placed into the injector of a GC where the heat causes the release of
************yte onto the column. This has been applied to endosulfan (α- and β-) and endosulfan sulfate in water
with limits of detection of less than 0.3 μg/L reported (Magdic and Pawliszyn 1996).
Measurements of endosulfan in air are made on samples forced through a collection device. The sample
is extracted with an organic solvent, followed by clean-up using column chromatography. GC, GC/MS,
and GC/ECD have been used to ************yze endosulfan in air samples. Method TO-4 (EPA 1988a) uses the
adsorption of the pesticides onto polyurethane foam in a high-volume sampler with subsequent extraction
and ************ysis using GC/ECD. Sensitivities on the order of 1 ng/m3 were reported. Kutz et al. (1976) used
a polyethylene glycol impinger for sample collection of ambient air from several sites throughout the U.S.
Extraction and clean-up were followed by quantitative ************ysis by GC/ECD. The lower limit of detection
using this method was 0.001–0.01 μg/m3.
GC/ECD or a halogen-specific detector (HSD) (Method 8080) is the technique recommended by EPA's
Office of Solid Waste and Emergency Response for determining α- and β-endosulfan and endosulfan
sulfate in water and waste water at low-ppb levels (EPA 1986a). At these low concentrations,
identification of endosulfan residues can be hampered by the presence of a variety of other pesticides.
Consequently, sample clean-up on a Florisil® column is usually required prior to ************ysis (EPA 1986a).
Methods 508, 508.1, and 525.2 (EPA 1997a, 1997b, 1997c) are applicable to drinking water and groundwater
and can determine α- and β-endosulfan and endosulfan sulphate at concentrations as low as 7 ppt
using liquid solid extraction (LSE) and GC/ECD.
GC/ECD and GC/MS (EPA Method 608) are the methods recommended for determining α-endosulfan,
β-endosulfan, and endosulfan sulfate in municipal and industrial discharges (EPA 1991a). Sample cleanup
on Florisil® column and an elemental sulfur removal procedure are used to reduce or eliminate
interferences. Sensitivity is in the sub-ppb range. Recoveries and precision are good.
ENDOSULFAN 218
6. ************YTICAL METHODS
A procedure has been developed for the ************ysis of α- and β-endosulfan and endosulfan sulfate in fish,
water, and sediments (Chau and Terry 1972; Musial et al. 1976). This procedure involves the acetylation
of endosulfan residues into their diacetates and subsequent quantification by GC/ECD. Detection limits
of low-ppb levels of endosulfan were reported. This approach is rapid and simple, and minimum sample
preparation is required (Chau and Terry 1972; Musial et al. 1976).
Numerous methods have also been reported for foods, including milk (Bennett et al. 1997), chili fruits
(Pokharkar and Dethe 1981), fruits and vegetables (Mitchell 1976), and the multiresidue methods for fatty
and non-fatty foods (fruits, vegetables, seeds, dairy, eggs, meats) published by FDA (FDA 1994). Limits
of detection are generally in the sub-ppm to ppb range.
Dreher and Podratzki (1988) developed an enzyme immunoassay technique for detecting endosulfan and
its degradation products (i.e., endosulfan diol, endosulfan sulfate, endosulfan ether, and endosulfan
lactone) in aqueous media. The enzyme immunoassay technique is based on detecting antibodies raised
against the diol of endosulfan by immunizing rabbits with an endosulfan-hemocyanin conjugate. Minor
problems were encountered with coupling of the detecting enzyme (peroxidase) to the conjugate and with
cross-reactivity with the pesticide endrin. Although the enzyme immunoassay technique does not require
sample extraction, and it is rapid and inexpensive, it is not yet in common use in environmental residue
************ysis. A detection limit of 3 μg/endosulfan/L of sample was achieved (Dreher and Podratzki 1988;
Frevert et al. 1988). Immunoassays have also been reported for endosulfan (both isomers), endosulfan
sulfate, and endosulfan diol in water and soil (Lee et al. 1997a, 1997b) with limits of detection reported to
be 0.2 μg/L for water and 20 μg/kg in soil. Details of commonly used ************ytical methods for various
environmental media are presented in Table 6-2.
6.3 ADEQUACY OF THE DATABASE
Section 104(i)(5) of CERCLA, as amended, directs the Administrator of ATSDR (in consultation with the
Administrator of EPA and agencies and programs of the Public Health Service) to assess whether
adequate information on the health effects of endosulfan available. Where adequate information is not
available, ATSDR, in conjunction with the National Toxicology Program (NTP), is required to assure the
initiation of a program of research designed to determine the health effects (and techniques for developing
methods to determine such health effects) of endosulfan.
ENDOSULFAN 219
6. ************YTICAL METHODS
Table 6-2. ************ytical Methods for Determining Endosulfan in Environmental Samples
Sample matrix Preparation method
************ytical
method
Sample detection
limit Percent recovery Reference
Air Pumping of air through glass fiber filter and
polyurethane foam plugs for collection;
extraction of plugs with petroleum ether and
filters with dichloromethane followed by
hexane reflux; clean-up on either Florisil/
alumina or silicic acid column
GC and GC/MS No data No data Bidleman 1981
Air Collection on polyethylene glycol impinger
and extraction with hexane; clean-up on
Florisil column
GC/ECD 0.001–0.01 μg/m3 No data Kutz et al. 1976
Air Collection of pesticide onto polyurethane
foam using high volume sampler; extraction
of PUF using 5% ether in hexane; extract
volume reduction; column clean-up
GC/ECD Approximately 1 ng/m3 >75% EPA 1988a
(Method TO-4)
Drinking water Extraction of water with methylene chloride,
removal of water from extract, volume
reduction to 5 mL after solvent exchange to
methyl-t-butyl ether
GC/ECD α-endosulfan:
0.015 μg/L (ppb);
β-endosulfan:
0.024 μg/L; endosulfan
sulfate: 0.015 μg/L
α: 87 (10% RSD)
β: 92 (11% RSD)
sulfate: 102 (15% RSD)
EPA 1997d
(Method 508)
Drinking water Extraction of water using C18 extraction
disks (LSE); elution using ethyl acetate and
methylene chloride; volume reduction
GC/ECD < 0.007 μg/L (α, β, and
sulfate)
88–106, (12–29% RSD) at
0.03 μg/L
EPA 1997e
(Method 508.1)
Drinking water Extraction of sample using LSE; solvent
elution; volume reduction
GC/MS 0.07 to 0.11 μg/L using
ITMS (α, β, and sulfate)
116–128 EPA 1997f
(Method 525.2)
Water Passage of samples through XAD-4 resin
column and extraction with methylene
chloride; clean-up extract with HPLC
GC/ECD 0.00001 μg/L 65.5 (at 0.01 μg/L Woodrow et al.
1986
Water Extraction of sample with methylene
chloride
GC/MS 10 μg/L 87 (α-endosulfan);
107 (β-endosulfan II);
71 (endosulfan sulfate)
Eichelberger et
al. 1983
ENDOSULFAN 220
6. ************YTICAL METHODS
Table 6-2. ************ytical Methods for Determining Endosulfan in Environmental Samples (continued)
Sample matrix Preparation method
************ytical
method
Sample detection
limit Percent recovery Reference
Water Extract ion of sample with toluene GC/ECD 0.5 μg/L (α-endosulfan);
0.5 μg/L
(β-endosulfan); 25 μg/L
(endosulfan sulfate)
99 (α-endosulfan);
99 (β-endosulfan); no data
(endosulfan sulfate)
Zoun et al. 1987
Water Adjustment of pH of sample to near neutral
and extraction with methylene chloride;
volume reduction; clean-up sample on
Florisil column
GC/ECD 0.5 μg/L (α-endosulfan);
0.1 μg/L
(β-endosulfan);
0.1 μg/L (endosulfan
sulfate)
No data Marsden et al.
1986
Water Development of antibodies against the diol
of endosulfan and its degradation products
EIA 3 μg/L No data Dreher and
Podratzki 1988;
Frevert et al.
1988
Water SPME of water; thermal transfer to GC GC/ECD α: 0.3 μg/L (ppb)
β: 0.4 μg/L (ppb)
Sulfate: 0.05 μg/L (ppb)
No data Magdic and
Pawliszyn 1996
Water, soil ************ysis of water directly; extraction of soil
with methanol followed by dilution of extract
with water
Immunoassay
(Total
endosulfan
including
endosulfan
sulfate and
endosulfan diol)
water: 0.2 μg/L (ppb)
soil: 20 μg/kg (ppb)
No data Lee et al. 1997a,
1997b
Water; waste
water
Extraction of sample with methylene
chloride and clean-up on Florisil column
GC/ECD 0.49 μg/L (α-endosulfan);
6.1 μg/L
(β-endosulfan); 2.7 μg/l
(endosulfan sulfate)
No data EPA 1986c
(Method 8080)
Municipal and
industrial
discharge
Extraction of sample with methylene
chloride; water removal; exchange to
hexane; volume reduction; clean-up on
Florisil column and removal of elemental
sulfur
GC/ECD;
GC/MS
0.014 μg/L (α-endosulfan);
0.004 μg/L
(β-endosulfan);
0.066 μg/L (endosulfan
sulfate)
97 (α-endosulfan);
93 (β-endosulfan);
89 (endosulfan sulfate)
EPA 1991b
(Method 608)
ENDOSULFAN 221
6. ************YTICAL METHODS
Table 6-2. ************ytical Methods for Determining Endosulfan in Environmental Samples (continued)
Sample matrix Preparation method
************ytical
method
Sample detection
limit Percent recovery Reference
Municipal and
industrial
wastewater;
sludge
Extraction with methylene chloride or
acetonitrile and methylene chloride
(depending on solids content); volume
reduction and clean-up using GPC, column
chromatography, or SPE; sulfur removal if
needed
GC/ECD α: 11 ng/L
β: 8 ng/L
sulfate: 7 ng/L
18–158 EPA 1992a
(Method 1656)
Water; fish Extraction of sample with organic solvents;
derivatize to the diacetate and ************yze
GC/ECD 0.005 μg/L 60–65 Chau and Terry
1972
Fish Grinding of sample and extraction with
toluene; clean-up extract on alumina column
GC/ECD 0.005 μg/L (α-endosulfan);
0.005 μg/L
(β-endosulfan);
0.025 μg/L (endosulfan
sulfate)
84 (α-endosulfan);
79 (β-endosulfan);
86 (endosulfan sulfate)
Zoun et al. 1987
Sediment Extraction of sample with organic solvent;
derivatize extract to the diacetate
GC/ECD 0.005–0.01 μg/g (ppm) No data Musial et al.
1976
Sediment; soil Extract of sample with methylene chloride:
acetone (1:1); clean-up extract using Florisil
column
GC/ECD 0.002 μg/g (ppm)
(α-endosulfan);
0.004 μg/g (β-endosulfan);
0.004 μg/g
(endosulfan sulfate)
No data Marsden et al.
1986
Non-fatty foods
(<2% fat, >
75% water)
Extraction with acetone and removal of
water with Hydromatrix; cleanup using
Florisil
GC/ECD No data >85% (α, β, sulfate) FDA 1994
(PAM Method
302)
Non-fatty foods
(<2% fat, <75%
water)
Extraction with acetonitrile, partition into
petroleum ether; cleanup using Florisil
GC/ECD No data >85% (α, β, sulfate) FDA 1994
(PAM Method
303)
Fatty foods
(>2% fat)
Extraction of fat using sodium sulfate,
petroleum ether, by filtering, or by solvents;
cleanup using solvent partitioning, Florisil
GC/ECD No data >85% (α, β, sulfate) FDA 1994
(PAM Method
304)
ENDOSULFAN 222
6. ************YTICAL METHODS
Table 6-2. ************ytical Methods for Determining Endosulfan in Environmental Samples (continued)
Sample matrix Preparation method
************ytical
method
Sample detection
limit Percent recovery Reference
Milk Extraction of milk with ethanol-ethyl acetate
(9: 95, v/v) with sodium sulfate;
centrifugation and volume reduction
GC/ELCD α: 0.9 μg/kg (ppb)
β: 0.9 μg/kg
Sulfate: 1.8 μg/kg
α: 90 (5% RSD)
β: 91 (11% RSD)
Sulfate: 88 (11% RSD)
Bennett et al.
1997
Chili fruits Homogenization of sample with
benzene:isopropanol (3:1); clean-up extract
using carbon:celite (1:1)
GC/ECD 0.005 μg per
sample
96.4 (α-endosulfan);
97 (β-endosulfan);
96.2 (endosulfan sulfate)
Pokharkar and
Dethe 1981
Fruits;
vegetables
Homogenization of sample with acetonitrile
and clean-up on Florisil column
GC/ECD <1 ppm (mg/kg) 101.5–103.6 (α-endosulfan);
100–102 (β-endosulfan);
92.9 (endosulfan
sulfate)
Mitchell 1976
GC = gas chromatography; ECD = electron capture detector; EIA = enzyme-immunoassay; GPC = gel permeation chromatography; HPLC = high-performance liquid chromatography;
ITMS = ion trap mass spectrometer; LSE = liquid solid extraction; MS = mass spectrometry; RSD = relative standard deviation; SPE = solid phase extraction
ENDOSULFAN 223
6. ************YTICAL METHODS
The following categories of possible data needs have been identified by a joint team of scientists from
ATSDR, NTP, and EPA. They are defined as substance-specific informational needs that if met would
reduce the uncertainties of human health assessment. This definition should not be interpreted to mean
that all data needs discussed in this section must be filled. In the future, the identified data needs will be
evaluated and prioritized, and a substance-specific research agenda will be proposed.
6.3.1 Identification of Data Needs
Methods for Determining Biomarkers of Exposure and Effect. GC/ECD, GC/MS, and
GC/MC are ************ytical techniques used for measuring endosulfan in blood, urine, hand rinses, and various
biological tissues and excreta at low- and sub-ppb levels (Coutselinis et al. 1976; Demeter and
Heyndrickx 1978; Demeter et al. 1977; Griffith and Blanke 1974; Guardino et al. 1996; Kazen et al.
1974; Le Bel and Williams 1986; Mariani et al. 1995; Williams et al. 1988). These techniques are
sensitive for measuring background levels of endosulfan in the population and levels of endosulfan at
which health effects might begin to occur. However, it should be noted that because endosulfan is used in
tobacco farming, background levels of endosulfan in the population may vary considerably, especially
between smokers and nonsmokers (Coleman and Dolinger 1982; WHO 1984). Although accurate and
reliable methods are available for ************ysis of endosulfan in biological tissues and fluids, insufficient data
have been collected using these techniques to correlate the concentrations of endosulfan in biological
materials with environmental exposure and health effects (see Chapter 2).
Sensitive, reliable biochemical assays have been used for measuring changes in enzyme activities (e.g.,
aminopyrine-N-demethylase, aniline hydroxylase) as an indication of exposure to endosulfan in animals
(Agarwal et al. 1978). Decreased red blood cells, hemoglobin, and IgG and IgM levels have also been
detected in animals following exposure to endosulfan (Banerjee and Hussain 1986, 1987; Das and Garg
1981; Hoechst 1985a; Siddiqui et al. 1987b). While well documented methods exist to monitor these
parameters, they are not specific for endosulfan exposure (see Chapter 2). However, if used in
combination with measurements of endosulfan and its metabolites in biological tissues and excreta, one or
more of these enzymatic and blood changes may prove to be useful biomarkers of exposure and effect.
There is a need for further research to correlate specific levels of endosulfan in biological media with
known biochemical changes that occur on exposure to endosulfan.
Methods for Determining Parent Compounds and Degradation Products in Environmental
Media. GC/ECD is the most prevalent ************ytical method for measuring low levels of α- and
ENDOSULFAN 224
6. ************YTICAL METHODS
β-endosulfan and endosulfan sulfate in water, waste water, soil, sediment, and foods (Bennett et al. 1997;
Chopra and Mahfouz 1977a; EPA 1986a, 1988a, 1991a, 1992; FDA 1994; Fisk 1986; Fukuhara et
al. 1977; Giabbai et al. 1983; Goebel et al. 1982; Kutz et al. 1976; Marsden et al. 1986; Mitchell 1976;
Noroozian et al. 1987; Pokharker and Dethe 1981; Woodrow et al. 1986; Zoun et al. 1987). This
technique is sensitive for measuring background levels of endosulfan in foods and water (media of most
concern for potential human exposure to endosulfan) and levels of endosulfan at which health effects
might begin to occur. The chronic oral MRL is 0.002 mg/kg/day, which translates to a required LOD of
0.07 mg/L, and these methods easily meet that need. GC/ECD or HSD is the method (Method 8080)
recommended by EPA (1986a) for detecting α- and β-endosulfan and endosulfan sulfate in water and
waste water at low-ppb levels. GC/ECD has also been used to detect low-ppb levels of α- and
β-endosulfan and endosulfan sulfate in foodstuffs, soil, and sediment.
An enzyme immunoassay technique has been employed for measuring endosulfan and its degradation
products (i.e., endosulfan diol, endosulfan sulfate, endosulfan ether, and endosulfan lactone) in water at
3 ppb (Chau and Terry 1972; Musial et al. 1976). However, this technique is not currently in use in
environmental residue ************ysis. Further research into this technique could produce a rapid, reliable, and
sensitive method for identifying contaminated areas posing a risk to human health. No additional
methods for detecting endosulfan in environmental media appear to be necessary at this time. However,
methods for the determination of endosulfan degradation products are needed.
6.3.2 Ongoing Studies
Researchers at the University of Florida Department of Food Science and Nutrition are evaluating the use
of liquid solid extraction for the determination of endosulfan and other pesticides in seawater and fish
(FEDRIP 1999). At the U.S. Department of Agriculture in Beltsville, Maryland, scientists are studying
the transport, deposition, and degradation of pesticides, including endosulfan. They stress the importance
of measuring both the α-and β-isomers because of the transformations (FEDRIP 1999). A technique
using solid phase extraction to sample water for endosulfan concentrations is being developed by the
University of Florida (FEDRIP 1999). The storage stability and transportability of endosulfan absorbed
by the disks will be studied to determine ************ytical efficiency. The Eastern Regional Research Center in
Wyndmoor Pennsylvania is developing advanced technologies for the ************ysis of endosulfan in meat,
poultry and eggs (FEDRIP 1999). This technique will include the use of a supercritical fluid extractor in
order to reduce the amount of organic solvent use and to speed up extraction times.
 

Grac đô thị không rác

Chủ đề mới

Thành viên trực tuyến

Không có thành viên trực tuyến.

Thống kê diễn đàn

Chủ đề
10,833
Bài viết
42,126
Thành viên
31,234
Thành viên mới nhất
khachmua