Multi-residue determination of tetracyclines in foods of animal origin

Summary

Tetracyclines (TCs) antibiotics are produced by actinomycetes and all belong to hydrogenated and tetrabenzene ring derivatives in their chemical structure and have similar physicochemical properties. Source: Food Safety Monitoring Technology (Chemical Industry Press)

Operation method

High Performance Liquid Chromatography

Materials and Instruments

Animal Liver Kidney Muscle Tissue Fish Products Milk
Polypropylene Disodium ethylenediaminetetraacetate Methanol-water Methanol-ethyl acetate Acetonitrile Trifluoroacetic acid
Polypropylene centrifuge tubes Solid phase extraction columns High performance liquid chromatography Tandem mass spectrometry

Move

1. Extraction

Animal liver, kidney, muscle tissue, aquatic products: weigh 5 g of homogenized sample (accurate to 0.01 g), placed in a 50 mL polypropylene centrifuge tube, respectively, with about 20 mL, 20 mL, 1O mL, 0.1 mol/L EDTA-Mcllvaine buffer solution (0.1 mol/L. Weighing 60.5 g of disodium ethylene diamine tetraacetic acid in 1625mL Mcllvaine buffer solution to dissolve, shake well) low temperature ultrasonic extraction three times, 3000 r/min, 5 min centrifugation (temperature below 15 ℃), combined with the supernatant (pay attention to the temperature below 15 ℃). Mcllvaine buffer solution to dissolve, shake well) low-temperature ultrasonic extraction three times, 3000 r/min, 5 min centrifugation (temperature lower than 15 ℃), combined supernatant (pay attention to the control of the volume of the total extract does not exceed 50 mL), and fixed volume to 50 mL, mixing, 5000 r/min, centrifugation for 10 min (temperature lower than 15 ℃), filtration, and to be purified.

Milk: Weigh 5 g of mixed sample (accurate to 0.01 g), put it in a 50 mL polypropylene centrifuge tube, dissolve it with 0.1 mol/L EDTA-Mcllvaine buffer solution and make it volume to 50 mL, vortex mixing for 1 min, low-temperature ultrasonication for 10 min, cool it to 4 ℃, 5000 r/min, centrifugation for 10 min (the temperature is lower than 15 ℃), and then filter it to be purified. ℃), filter, and wait for purification. The sample was then filtered and allowed to be purified.

2. Purification

Accurately aspirate 10 mL of the extract at a rate of 1 drop/s through the Waters Oasis HLB (60 mg, 3 mL) solid phase extraction column, after the supernatant completely flowed out, the supernatant was drenched with 5 mL of water and 5 mL of methanol-water (5 + 95) in turn, and all the effluent was discarded. The column was dried under reduced pressure for 5 min and finally eluted with 10 mL of methanol-ethyl acetate (10 + 90). The eluate was blown nitrogen and concentrated to dryness (temperature less than 30 ℃), and the residue was dissolved with 1.0 mL of standard diluent, sonicated at low temperature for 5 min, and then passed through a 0.45 um filter membrane for determination by high performance liquid chromatography/tandem mass spectrometry (HPLC/MS).

3. 5HPLC measurement conditions

Column: Inertsi1 C8-3, 5 um, 150 mm×2.1 mm;

Mobile phase: methanol, acetonitrile, 0.01 mol/L trifluoroacetic acid, elution gradient is shown in Table 3-11 (column equilibration time 5 min);



Flow rate: 1.5 mL/min;

Column temperature: 30 ℃;

Injection volume: 30 uL.

4. HPLC-MS/MS measurement conditions

Column: Inertsil C8-3, 50 m, 150 mm × 2.1 mm;

Flow rate: 0.3 mL/ min;

Column temperature: 30 ℃;

Injection volume: 300 L;

Mobile phase: methanol + 0.01 mol/L trifluoroacetic acid.

Ionization mode: ESI+ ;

Mass spectral resolution: unit resolution;

Nebulizing gas (NEB): 6.0 L/min;

Curtain gas (CUR): 10.0 L/min;

Spraying voltage (IS): 4500 V;

Desolventization temperature (TEM): 500 Temperature of desolventization (TEM): 500 ℃ ;

Desolventizing airflow: 700 L/min;

Collision air (CAD): 6.0 L/min (nitrogen).

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