Modification of AOAC multiresidue method for determination of synthetic pyrethroid residues in fruits, vegetables, and grains. Part I: Acetonitrile extraction system and optimization of florisil cleanup and gas chromatography.
We present a multiresidue method for determination of synthetic pyrethroids in fruits, vegetables, and grains. The method is a modification of AOAC Method 970.52. Residues are extracted with acetonitrile (for fruits and vegetables) or acetonitrile-water (2 + 1) (for grains) and then transferred to hexane. Coextractives are removed by acetonitrile partitioning and open-column chromatography with deactivated Florisil. The final extract is analyzed by gas chromatography with electron capture detection (GC-ECD). An HP-17 wide-bore column is used to determine the individual isomeric contents of each insecticide. The method was used to recover 8 pyrethroids (biphenthrin, fenpropathrin, cyhalothrin, permethrin, cypermethrin, fluvalinate, fenvalerate, and deltamethrin) spiked at 0.01-4.0 mg/kg in 20 crops (apple, pear, peach, banana, grape, strawberry, potato, tomato, cucumber, pepper, cabbage, carrot, celery, polished rice, wheat, green gram, buckwheat, sorghum, maize, and barley). Recoveries of the 8 pyrethroid insecticides in 6 crops ranged from 83.8 to 112.8%, with a coefficient of variation (CV) of 2.00 to 12.09% for the narrow-bore capillary GC (n = 6) and from 82.8 to 106.4%, CV = 2.93-12.19%, for the wide-bore capillary GC (n = 6). The minimum detectable levels of 0.004-0.028 mg/kg (for fruits and vegetables) or 0.01-0.08 mg/kg (for grains) for the 8 pyrethroids are easy to detect.
Pang
G F
GF
Qinhuangdao Import and Export Commodity Inspection Bureau, Hebei, People's Republic of China.
Chao
Y Z
YZ
Fan
C L
CL
Zhang
J J
JJ
Li
X M
XM
Zhao
T S
TS
D000097:Acetonitriles; D002849:Chromatography, Gas / Q000379:methods*; D002523:Edible Grain / Q000737:chemistry; D005504:Food Analysis; D005506:Food Contamination; D005638:Fruit / Q000737:chemistry; D007306:Insecticides / Q000032:analysis*; D017633:Magnesium Silicates; D010573:Pesticide Residues / Q000032:analysis*; D011722:Pyrethrins / Q000032:analysis*; D014675:Vegetables / Q000737:chemistry
D000097:Acetonitriles; D007306:Insecticides; D017633:Magnesium Silicates; D010573:Pesticide Residues; D011722:Pyrethrins; C005013:Florisil; C032159:acetonitrile