Nghiên cứu xác định dư lượng thuốc trừ sâu nhóm lân hữu cơ và cúc tổng hợp trong một số rau quả tươi tại tp cao lãnh, tỉnh đồng tháp bằng phương pháp sắc ký khí ghép khối phổ (GC MS)















TP.CAO LÃNH, 










, 2014




















Chuyên ngành : Hóa phân tích
















             PGS. TS.
 
trong 
Em 
-    

Em 



Sau cùng  
  này!.







- ADI (Acceptable Daily Intake): 
- 
- CI (chemical ionization trên GC/MS
- DSPE (Dispersed Solid Phase Extraction
- ECD (Electron Capture detector
- EI (Electron Ionization
- FID (Flame Ionization detector
- GC (Gas chromatography
- HPLC (High Performance Liquid Chromatography
cao.
- LD
50
(Letal Dois) : 
- LC
50
(Letal Concentration): 
- LOD (Limit of detection
- LOQ (Limit of Quantification
- MRL (Maximum Residue Level): 
- MS (Mass Spectrometry
- NPD (Nitrogen Phosphorous detector): 
Phospho
- QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe): Nhanh, d,
r, hiu qu, nh, và an toàn.
- RF (Fluorescence
- RSD (Relative Standard Deviation

- SEC (Size Exclusion
- SD (Standard Deviation
- 
- UV- 




 

 
 

 
 
2
)
: 

anh



 
Bang 3.11: 
 
 
 
 
 

 3.17: 



 GC/MS



.5:
Hình 1.6.
Hình 1.7. 
 Khong tuyn tính và khong làm
vic

Hình 1.9: ng chun trên n m
thc

Hình 1.10: ng chun s dg ch ni
chun

Hình 1.11: Mi quan h gia LOD, LOQ và khong tuyn
tính
Hình 2.1: 



a peak diazinone






 3.10:
Hinh 3.11:
Hinh 3.12:
Hình 3.13:
Hình 3.14: ngót
Hình 3.15:

1



chia rau 
  

Rau 


hàng ngày qua rau   

rau 


bón.
     B  T       rau





           

        
.[20]


             cho phép là
6,44% trong   trong  trong  
trong 

2

 [20]
 
(BVTV) 
[8]
các             






Các t         
(GC/    ghép   (GC/MS, GC/
UV- ghép 
(LC/MS, LC/
b




(MS) 




p 
lý do trên chúng : xác

rau T Cao Lãnh, 

3
 
.
chúng 
-         và
.
- 

-TTS 
và 
-
- 

- 

- 

-  phân tích 
      rau     

.







4

1

1.1. GII THIU V THUC BO V THC VT
 [3]
1.1.1.1. Thuc bo v thc vt:
- Thuc bo v thc vt (sn phc) : là nhng ch phm
có ngun gc hóa cht, thc vng vt, vi sinh vt và các ch phm khác
 phòng tr sinh vt gây hi tài nguyên thc vt. Gm các ch phm
 phòng tr sinh vt gây hi tài nguyên thc vt; các ch phu
ng thc vt; cht làm rng hay khô lá; các ch phm có tác dng
i hoc thu hút các loi sinh vt gây hi tài nguyên thc v tiêu
dit.
-  

- 

ng thuc bo v thc vt (BVTV):

             
              

BVTV.

ADI 
h là mg/kg

1.1.1.4. Gii hn tng (MRL) thuc bo v thc vt:
- 


5


(1)
BM ng trung bình/
F  trung bình/i/ngày
ADI 
ngày 


1.1.2. Phân loi thuc bo v thc vt: [3]
:



cô
 








(Acricide hay Miticide):




.

6



        

1.1.2.2. 



 

              
th
 


     




 
 

1.1.2.3. 


+   



7
+  

+ 
 
.
1.1 c [3]
1.1.3.1. c tính: là kh c  sinh vt 
mng nhnh ca ch
1.1.3.2.  c: là biu hin m cc, là
   sinh v
ác ch c khác nhau và
 c biu th là miligam chc trên kilogam tr 
(mg/kg) hoc µg/mg vi nhng vt nh c biu th qua liu
gây cht trung bình (Letal Dois  LD
50
) hoc n gây cht trung bình
(Letal Concentration  LC
50

ng thuc ít nht có th gây cht 50% s
cá th vt thí nghic tính bng mg/kg, nên các loi thuc BVTV có
LD
50
hoc LC
50
càng th cao càng cao.
1.2. : [3]
          
             bamat


chúng 


GC/MS).

8
1.2.1. Nhóm lân h [3]
1.2.1.1:







  

- Lân h  ch thng: malathion, dimethoate, acephate,


- Lân ha gc phenyl: parathion ethyl, profenofos, fenitrothion,
prothiofos, isof

.1 :
.1: To và dung môi hòa tan
  [15], [17]
Tên



Dung môi
hòa tan
Chlorfenvinphos

- Tan trong H
2
O: 145
mg/L (23
o
C).
- Tan trong acetone,
ethanol, propylen glycol.
Chlorpyrifos-Ethyl

- Tan trong H
2
O: 2 mg/l
(25
o

C).
- Tan trong isooctane:
79% w/w; methanol: 43%
w/w
- Tan nhanh trong các
P
R - O
R - O
O  (hay S  
2
, Cl)
O (hay S)

9
dung môi h
Chlorpyrifos-methyl

- Tan trong H
2
O: 5 mg/l
(25
o
C).
- Tan trong isooctane:
79% w/w; methanol: 43%
w/w
- Tan nhanh trong các
dung môi h
Diazinone

- Tan trong H
2
O: 0,004%
(20
o
C).
- Hòa tan trong alcohol,
ether, petrolium ether,
cyclohexane, benzene,
hydrocarbons.
Disulfoton

- Không tan trong H
2
O.
- Tan trong các dung môi
h

1.2.1.2. m chung:



       



1.2.1.3.  ng:

      


    


10




cholinesterase (


vong.
1.2.2. Nhóm cúc tng hp (Pyrethroid): [3]
1.2.2.1
Nhóm cúc tng hp (Pyrethroid) là hn hp ca các este có cu trúc
ng phân quang hc ca mt gc axit, 1 hoc 2 nguyên t i
xng vi mt g u có cha mt hoc không cha nguyên t cacbon
i xng. Các hp chc tng hp da trên các hp cht t
nhiên có trong cây cúc sát trùng.
Da vào tính bn vi vi ta chia nhóm pyrethroid
thành 3 nhóm:
+ Không bn vi ánh sáng: allethrin, resmethrin
i bn vi ánh sáng: deltamethrin, permethrin, fenvalerat
+ Bn vi ánh sáng: cypermethrin, bifethrin, cyhalothrin, cyfluthrin
Mt s hp cht nhóm cúc tng hp nghiên c c trình
bày trong bng 1.2:

11
1.2: To và dung môi hòa tan
  [15], [17]

Tên



Dung môi
hòa tan
Cypermenthrine

- Không tan trong H
2
O.
- Tan trong MeOH,
acetone, xylene, CH
2
Cl
2
.
Cyfluthrin

- Tan trong H
2
O: 1-2 x
10
-6
g/L (20
o
C).
- Tan trong các dung môi
h
Permethrine

- Tan trong H
2
O: < 1
mg/L
- Tan trong các dung môi
h tr ethylene
glycol.
Phenothrine

- Không tan trong H
2
O.
- Tan trong acetone,
xylene.

m chung:
Nhóm cúc tng hp có nhi sôi cao, áp sup, ít phân cc tan
tt trong dung môi h
Thuc tr sâu nhóm cúc tng hp có ph tác dng rng dic các
loi côn trùng có cánh bng ti c không tác dng
thm sâu và ni hp, ngoài ra nhóm cúc tng hp còn có tác di.

12
 c ca thui vi côn trùng ph thuc vào tính phân cc và cu
tng phân quang hc, nó có tính quynh hiu lc ca thuc m
là s i thành phn hoá hc có trong chúng, vì nhóm cúc tng hp là
hn hp ca các este có cng phân quang hc khác nhau mng
phân có hot tính sinh hc rt khác nhau nên ving phân này ra
i k thu phân gii cao.

 ng:




h
.
 ng vt máu nóng nhóm cúc tng hp b phân hu và thi
ra bên ngoài nên không gây tích lu .
1.3 C KÝ [1], [2]
1.3.1. Khái nim Phân loi sc ký :



         -  
- 
    

/

 


13


(Liquid Chromatography- Chromatography- GC).
1.3
 


0

2
, N
2
,




 


1.3.3. Cu to máy s
              
mang, , 


1.1 GC/MS

14

1.3.3.1. Khí mang (Carrier gas): 
khí Helium

          

: B

1.3:

    g    
       
     c   
  
tiêm
: 

1.3):

1.4: 




15

 c, 

dòng và không chia dòng.
-           

              

-  Mc
tiêm vào bung tiêm nóng (nhi bung tiêm ph  toàn b dung
d cu th 10
0
C- 30
0
C so vi nhi sôi

c to hiu ng dung môi (solvent effect) nhm gi các cht
nm  u ct mà không di chuyn trong thu vào ct (t 30- 60
giây). Sau thc m ra và quá trình phân tích
bu cùng vi nhi cng th tích mu không quá 2 µL
c tiêm vào bu tránh nhim bn các b phn khác.
1.3oven)



: 
1.3

-
 



Hình 1.6. Cu to ct s


16
1.3u dò khi ph (MS Detector)

Hình 1.7. Cu to u dò khi ph
         -   


 
ABCDE + e  [ABCDE]
+.

+ 2e

[ABCDE]
+.
 [ABC]
+
+ [DE]
.
[ABC]
+
 [AB]
+
+ C

[AB]
+
 [A]
+
+ B

[ABC]
+
, [AB]
+
, [A]
+

 80eV,
.



- ectron impact - 

 
         200±0.25
o
C. Các electron va
  trung hoà  trung
 


17
- - CI): Ion hóa hóa
h  
 trung hòa thành ion phân 

2
, CH
4
, H
2
O, CH
3
OH, NH
3

nh
d hóa
.


Phân t khí
Tác nhân ion d
H
2

CH
4

H
2
O
CH
3
OH
i-C
4
H
10

NH
3

(CH
3
)
2
CO
H
3
+

CH
4
+
,CH
3
+
, CH
5
+
, C
2
H
5
+
, C
3
H
7
+

H
+
, (H
2
O)n
H
+
, (CH
3

OH)n
C
4
H
9
+
, C
3
H
3
+

H
+
, (NH
3
)n
(CH
3
)
2
CO
+

Ion hóa  ion d  ra theo các b sau:
c1: phân t trung hòa (CH4) va chm vi dòng electron mang 
lng cao tr thành ngun ion.
CH
4
+ e  CH

4
+.
+ 2e
CH
4
+.
+ CH
4
 CH
5
+
+ CH
3
+

CH
4
+.
 CH
3
+
+ H
CH
4
+.
 CH
2
+.
+ H
2

CH
3
+
+ CH
4
 C
2
H
5
+
+ H
2

CH
2
+.
+ CH
4
 C
2
H
4
+.
+ H
2

CH
2
+.

+ CH
4
 C
2
H
3
+
+ H
2
+ H
C
2
H
3
+
+ CH
4
 C
3
H
5
+
+ H
2

c2: các ion du này va chm vi phân t mu dng khí
CH
5
+
+ MH  CH

4
+ MH
2
+
(MH là mu cht)
CH
3
+
+ MH  CH
4
+ M
+

CH
4
+.
+ MH  CH
4
+ MH
+.

18
1.4. NG THUC BVTV
1.4.1. Cách ly mng. [5]

:
1.4: 




rau 

 





lách
 









Nhóm rau 5



t và làm sch mu:
t tách mu: [4], [12], [13], [14], [16], [18]
a. Chit bng dung môi.
           

             
du



19



           
4
hay
Na
2
SO
4





b. Chit phân tán pha rn (Matrix Solid Phase Dispersion
Extraction).

u sau khi
x
18
, C
8

      




     asy, Cheap, Effective,
Rugged, and Safe)


,






4
