Determination of benzoylurea insecticides in food by pressurized liquid extraction and LC-MS.
A method based on pressurized liquid extraction and LC-MS/MS has been developed for determining nine benzoylureas (BUs) in fruit, vegetable, cereals, and animal products. Samples (5 g) were homogenized with diatomaceous earth and extracted in a 22 mL cell with 22 mL of ethyl acetate at 80 degrees C and 1500 psi. After solvent concentration and exchange to methanol, BUs were analyzed by LC-MS/MS using an IT mass analyzer, which achieved several transitions of precursor ions that increase selectivity providing identification. LOQs were between 0.002 and 0.01 mg/kg, which are equal or lower than maximum residue limits established by the Codex Alimentarius. Excellent linearity was achieved over a range of concentrations from 0.01 to 1 mg/kg with correlation coefficients 0.995-0.999 (n=7). Validation of the total method was performed by analyzing in quintuplicate seven different commodities (milk, eggs, meat, rice, lettuce, avocado, and lemon) at three concentration levels (0.01, 0.1, and 1 mg/kg). The recoveries ranged from 58 to 97% and the RSDs from 5 to 19% depending on the compound and the commodity. The combination of pressurized liquid extraction with LC-MS/MS provides a sensitive and selective method for the determination of BUs in food.
Brutti
Monia
M
Laboratori de Nutrició i Bromatologia, Facultat de Farmàcia, Universitat de València, Valencia, Spain.
Blasco
Cristina
C
Picó
Yolanda
Y
D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D005638:Fruit / Q000737:chemistry; D007306:Insecticides / Q000032:analysis*; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000379:methods*; D008460:Meat / Q000032:analysis; D008782:Methylurea Compounds / Q000032:analysis*; D015394:Molecular Structure; D010573:Pesticide Residues / Q000032:analysis; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D014675:Vegetables / Q000737:chemistry
D007306:Insecticides; D008782:Methylurea Compounds; D010573:Pesticide Residues; D012997:Solvents