SN/T 1627-2005Determination of merabolites of nitrofurans residues in animal origin food for import and export. HPLC-MS/MS (English PDF)

2.1 Method summary

The protein-bound nitrofuran metabolite (see Appendix A) is hydrolyzed and freed in an acidic environment with o-nitrobenzene After formaldehyde was derivatized, it was extracted with ethyl acetate. After purification and concentration, it was measured by a liquid chromatography mass spectrometer. Quantification by external standard method.

2.2 Reagents and materials

Unless otherwise specified, the reagents used were of analytical grade and the water was ultrapure water.

2.2.1 Acetonitrile. HPLC grade.

2.2.2 Methanol. HPLC grade.

2.2.3 Ethyl acetate. HPLC grade.

2.2.4 o-nitrobenzaldehyde.

2.2.5 Dimethyl sulfoxide.

2.2.6 anhydrous sodium sulfate. 650 ° C burning for 4h, cooled and stored in a closed container for use.

2.2.7 Hydrochloric acid solution. 0.125 mol/L.

2.2.8 Sodium hydroxide solution. 1 mol/L.

2.2.9 Sodium hydroxide solution. 0.1 mol/L.

2.2.10 Sodium chloride solution. 300g/L.

2.2.11 Hydrochloric acid solution. 1 mol/L.

2.2.12 Derivatization reagent. Weigh 100 mg of o-nitrobenzaldehyde in 12.5 mL of dimethyl sulfoxide, and use it now.

2.2.13 Constant volume solution. 0.1% aqueous acetic acid. acetonitrile. methanol 3.3.2 (volume fraction).

2.2.14 Nitrofuran metabolite standards. AOZ, AMOZ, AHD·HCl, SEM·HCl, purity >=99.0%.

2.2.15 Standard stock solution. weigh nitrofuran metabolite standard AOZ, AMOZ10.0mg, AHD·HCl

13.2mg, SEM·HCl 14.9mg (accurate to 0.1mg), dissolved in methanol and transferred to a 20mL volumetric flask, determined with methanol the solution was allowed to reach a mark, and the concentration of the solution was 0.5 mg/mL, and it was stored at 4 ° C or lower.

2.2.16 Standard intermediate solution. separately absorb 1.0 mL of each standard stock solution of four nitrofuran metabolites, and dilute to 50 mL with methanol.

The concentration was 10 µg/mL.

2.2.17 Standard working solution. Take 1.0 mL of standard intermediate solution, dilute to 100 mL with methanol, and the concentration is 0.1 µg/mL.

2.2.18 Calibration curve standard working solution. Dilute the standard working solution to the appropriate concentration to make the calibration curve, and prepare it when it is ready.

2.3 Instruments and equipment

2.3.1 Liquid chromatography mass spectrometer for secondary mass spectrometry analysis.

2.3.2 Electronic balance.

2.3.3 Ultrasonic cleaner.