Determination of 5 Benzimidazole Drug Residues in Milk and Milk Powder by Liquid Chromatography Tandem Mass Spectrometry

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It is suitable for the determination of thiabendazole, albendazole, fenbendazole, oxfendazole and thiocarbamate residues in milk and milk powder by liquid chromatography-tandem mass spectrometry

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Milk and milk powder samples thiabendazole , albendazole , fenbendazole , oxfendazole , and phenylthio urethane residue by acetonitrile extraction, C _{18 is} solid-phase extraction (SPE), liquid chromatography - tandem mass spectrometry Measured by instrument and quantified by external standard method

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Acetonitrile, methanol : chromatographically pure; n-propanol, sodium bicarbonate (NaHCO ₃ ), sodium carbonate (Na ₂ CO ₃ ): analytically pure

Sodium bicarbonate solution: 0.

The purity of the standard materials of thiabendazole, albendazole, fenbendazole, oxfendazole and thiocarbamate are all ≥99%

Standard stock solution: 1.

Mixed standard stock solution: 100μg/mL

Matrix mixed standard working solution: According to the sensitivity of each standard and the linear range of the instrument, draw a quantitative mixed standard stock solution, use the blank sample extract to prepare a series of concentrated matrix mixed standard working solution, and prepare it on the same day

C ₁₈ solid phase extraction column: 500mg, 6mL

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Liquid chromatography-tandem quadrupole mass spectrometer, equipped with electrospray ion source; analytical balance: 0.

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(1) Sample preparation

Take about 500g of representative sample, mix well, put it into a clean container, seal it, and mark it

(2) Extraction

Milk sample: Weigh 10g milk sample, accurate to 0.
01g, and place it in a 100mL centrifuge tube with stopper
.
Add 30mL acetonitrile, vortex for 3min, sonicate for 30min, centrifuge at 4000r/min for 5min, take the supernatant and add 10mL n-propanol, remove the organic solvent by rotary evaporation in a 40℃ water bath, and dilute to 10mL with carbonate buffer solution
.

Milk powder sample: Weigh 12.
5g milk powder sample in a beaker, add an appropriate amount of 35～45℃ water to fully dissolve it, after cooling to room temperature, add water to 100g, mix well, accurately weigh 10g sample, accurate to 0.
01g , Placed in a 100mL centrifuge tube with stopper, and processed according to the above steps
.

(3) Purification

Pipette 5 mL of the extract and inject it into the pretreated C18 solid phase extraction column, adjust the flow rate to 1.
0 mL/min, rinse with 5 mL of water, discard all the effluent, and drain
.
Elute the test substance with 6 mL of acetonitrile, flow rate 1.
0 mL/min, blow dry with nitrogen in a 40℃ water bath, then dissolve it with methanol solution (1+4, v/v) and dilute to 1.
0 mL, pass through a 0.
2μm filter membrane, and supply Liquid chromatography-tandem mass spectrometry determination
.

Related Links: Determination of Benzimidazole Drugs-Gas Chromatography