Determination of 14 β-lactam veterinary drug residues in foodstuffs of animal origin

Summary

If veterinary drugs are used inappropriately or without a prescribed rest period, they can lead to excessive residues of veterinary drugs in animal foods, and the problem of veterinary drug residues in foods is becoming increasingly serious as human consumption of animal foods increases. The risk of veterinary drug residues to human health is related to different drug types and drug residue levels. Source: Food Safety Monitoring Technology (Chemical Industry Press)

Operation method

HPLC-MS/MS method

Materials and Instruments

Animal liver Kidney Muscle Egg Milk
Acetonitrile Sodium hydroxide Phosphate buffer
Chicken heart flasks Rotary evaporator Colorimetric tubes Vortex mixer Centrifuge tubes

Move

1. Extraction Animal liver, kidney and muscle tissues: weigh 5.0 g of crushed sample in a 50 mL centrifuge tube, add 15 mL of acetonitrile-water (15 + 2), homogenize and extract for 30 s, centrifuge at 4000 r/min for 5 min, and transfer the clear solution to a 50 mL colorimetric tube; take another centrifuge tube, add 10 mL of acetonitrile-water (15 + 2), and wash the head of the homogenizer for 10 s. Pound the precipitate in the centrifuge tube with a glass rod. Pound the precipitate in the centrifuge tube, add the above solution of washing homogenizer tip, shaking on a vortex mixer for 1 min, centrifuging at 4000 r/min for 5 min (centrifuge temperature 20 ℃), the supernatant was combined into a 50 mL cuvette, and then washed the tip of tip and extracted with 10 mL of acetonitrile-water (15 + 2) for one time, and then combined to 40 mL, and then 20 mL of the supernatant was taken into a 100 mL chicken-centered flask. Eggs: weigh 10.0 g of sample in a 50 mL centrifuge tube, add 15 mL acetonitrile-water (15 + 2), homogenize and extract for 30 s, centrifuge at 4000 r/min for 5 min, and transfer the clear solution to a 50 mL colorimetric tube; take another centrifuge tube, add 10 mL acetonitrile-water (15 + 2), and wash the homogenizer cutter head for 10 s; mash the precipitate in the centrifuge tube with a glass rod, and add it to the above solution. Wash the homogenizer tip solution, oscillate on a vortex mixer for 1 min, centrifuge at 4000 r/min for 5 min (centrifuge temperature 20 ℃), the supernatant was combined into a 50 mL colorimetric tube, and the tip was washed and extracted with 10 mL of acetonitrile-water (15 + 2) repeatedly, and then combined and fixed to 40 mL, and then 20 mL of the supernatant was taken to 100 mL chicken-centered bottles. Milk: Weigh 10.0 g of sample in a 50 mL centrifuge tube, add 20.0 mL of acetonitrile, homogenize and extract for 30 s, centrifuge at 4000 r/min for 5 min, and transfer the supernatant to a 50 mL colorimeter tube; take another centrifuge tube, add 10 mL of acetonitrile-water (15 + 2), and wash the homogenizer cutter head for 10 s; mash the precipitate in the centrifuge tube with a glass rod, and add the above homogenizer washing solution. Wash the homogenizer tip with 10 mL acetonitrile-water (15+2), add the above homogenizer tip washing solution, oscillate for 1 min in a vortex mixer, centrifuge for 5 min at 4000 r/min (centrifuge temperature: 20 ℃), and then add the supernatant into a 50 mL tube, and then wash the tip with 10 mL acetonitrile-water (15+2) and extract the supernatant, and then combine the two solutions to 50 mL, and then add 25 mL of supernatant into a 100 mL cocktail flask. The bottle was placed on a rotary evaporator (37 ℃ water bath) and evaporated until the acetonitrile was removed (4 mL of saturated sodium chloride solution may be added for samples prone to foaming). 2. Purification Immediately add 25 mL of phosphate buffer solution (pH 8.5) to the acetonitrile-removed vial, vortex and mix for 1 min, adjust the pH to 8.5 with 0.1 mol/L sodium hydroxide, and then pass through the pre-treated solid-phase extraction cartridge at a rate of 1 mL/min, firstly wash with 2 mL of phosphate buffer solution twice, and then wash with 1 mL of ultrapure water. The column was eluted with 3 mL acetonitrile (at a controlled rate of 1 mL/min). The eluate was blown dry under nitrogen at 45 ℃, and then fixed with 25 mmol/L phosphate buffer solution (pH 7.0) to 1 mL. After passing through a 0.45 um filter membrane, it was used for the determination by liquid chromatography-tandem mass spectrometry. 3. Determination conditions Chromatographic column: COSMOSILC18 column, 250 mm×4.6 mm, particle size 5 um; Mobile phase: acetonitrile for component B, 0.01 mol/L ammonium acetate for component A (pH adjusted to 4.5 by formic acid) with gradient elution; Flow rate: 1.0 mL/ min; Column temperature: 40 ℃; Injection volume: 10 uL.

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