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1.
Determination of multi-component residues of carbamate pesticides in meat, eggs and dairy foods
Carbamate pesticides (NMCs) following the organophosphorus a pesticide after emergence, mainly aldicarb, A Naiwei , carbofuran , metolcarb, isoprocarb the like
.
Due to the instability of NMCs and high temperature decomposition, high performance liquid chromatography has become the main and commonly used method for detecting NMCs (according to GB/T5009.
1.
Principle
The sample is extracted, purified, concentrated, constant volume, filtered by a microporous membrane, and then injected.
The sample is separated by reversed-phase high performance liquid chromatography and detected by an ultraviolet detector.
The sample is qualitatively based on the retention time of the chromatographic peak and quantified by an external standard method
.
Calculate as follows:
Where x——the content of each pesticide in the sample, mg/kg
m 1 ——the quality of each pesticide in the tested sample solution, ng
m——Sample mass, g
V 1 ——Injection volume of test solution, uL
V 2 ——The final constant volume of the sample, mL
2.
Chromatographic conditions
Chromatographic column: AltimaC 18 column (250mm×4.
6mm); mobile phase: methanol +water (60+40); flow rate 0.
5mL/min; column temperature: 30°C; UV detection wavelength: 210nm
.
3.
Tips
(1) This method is suitable for the determination of aldicarb, sulfacarb, carbofuran, carbaryl, and isoprocarb residues in meat, eggs and dairy foods
.
(2) The detection limits were aldicarb 9.
8ug / kg, metolcarb 7.
8ug / kg, carbofuran 7.
3ug / kg, carbaryl 3.
2ug / kg, isoprocarb 13.
3ug / kg
.
3.
Determination of 500 pesticides and related chemical residues in fruits and vegetables
"GB/T19648-2006 Determination of 500 Pesticides and Related Chemical Residues in Fruits and Vegetables" stipulates the use of gas chromatography-mass spectrometry
.
1.
Principle
The sample was extracted with acetonitrile homogenate, after salting out and centrifugation, the supernatant was taken, purified by solid phase extraction column, and acetonitrile + toluene (3+1) was used to elute pesticides and related chemicals.
After solvent exchange, gas chromatography-mass spectrometry was used Instrument detection
.
The measurement result can be automatically calculated by the computer according to the internal standard, or it can be calculated by the following formula:
In the formula, X——the residual amount of the tested substance in the sample, mg/kg
p 1 ——The concentration of the analyte in the standard working solution of the matrix, ug/mL
A 1 ——The chromatographic peak area of the test substance in the sample solution
A 2 ——The chromatographic peak area of the analyte in the matrix standard working solution
p 2 ——concentration of internal standard substance in sample solution, ug/mL
p 3 ——Concentration of internal standard substance in matrix standard working solution, ug/mL
A 3 ——The chromatographic peak area of the internal standard substance in the matrix standard working solution
A 4 ——The chromatographic peak area of the internal standard substance in the sample solution
V——The final constant volume of the sample solution, mL
m——the mass of the test solution represented by the sample solution, g
2.
Tips
(1) This standard applies to the determination of 500 pesticides and related chemical residues in apples, citrus, grapes, cabbage, celery, and tomatoes
(2) The detection limit of this standard method is 0.
Related Links: Determination of Multi-residue Organophosphorus Pesticides in Fruits, Vegetables and Cereals
