National Standards of the People's Republic of China National Standards
Determination of oxytetracycline, tetracycline and chlortetracycline residues in livestock and poultry meat GB/T 14931.1-94
(High Performance Liquid Chromatography)
Method for determination of oxytetracyline tetracyline and
Chlortetracycline residues in meat (HPLC)
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1 Theme content and scope of application This standard specifies the detection methods for terramycin, tetracycline and chlortetracycline residues in livestock and poultry meat.
This standard applies to the determination of terramycin, tetracycline and chlortetracycline residues in various edible livestock and poultry meat. The lowest detected concentrations were: 0.15, 0.20, 0.65 mg/kg.
Principle 2 Samples were extracted, filtered directly on the microporous membrane, and separated by reversed-phase chromatography. The detection was performed by a UV detector and compared with the standard. The order of the peaks was oxytetracycline, tetracycline, and chlortetracycline. Standard addition quantification.
3 Reagents
3.1 Acetonitrile (Analytical Pure).
3.2 0.01 mol/L sodium dihydrogen phosphate solution: Weigh 1.56 g (±0.01g) sodium dihydrogen phosphate (NaH2PH4.2H2O) in distilled water, dilute to 100 mL, and filter through a microporous membrane (0.45 μm). ,spare.
3.3 Oxytetracycline (OTC) standard solution: Weigh oxytetracycline 0.0100g (± 0.0001g), with 0.1mol/L hydrochloric acid solution containing oxytetracycline 1mg per milliliter.
3.4 tetracycline (TC) standard solution: Weigh tetracycline 0.0100g (± 0.001g), dissolved in 0.01mol/L hydrochloric acid solution and make up to 10.00mL, this solution contains tetracycline 1mg per milliliter.
3.5 Chlortetracycline (CTC) standard solution: Take chlortetracycline 0.0100g (± 0.0001g), dissolved in distilled water and set to 10.00
mL, this solution contains 1 mg of chlortetracycline per ml.
The above standard products are converted by 1000 units/mg. 3.3 ~ 3.5 solution should be stored below 4 °C, can be used for 1 week.
3.6 mixed standard solution: take 1.00 mL each of 3.3, 3.4 standard solution, take 2.00 mL of 3.5 standard solution, and put it in 10mL
In the flask, add distilled water to the mark. This solution contains oxytetracycline, tetracycline each 0.1mg, chlortetracycline 0.2mg per milliliter, temporarily with the current allocation.
3.7 5% perchloric acid solution.
4 Instruments
4.1 High Performance Liquid Chromatography (HPLC): UV detector.
5 chromatographic conditions
5.1 Column: ODS-C18 (5 μm) 6.2 mm × 15 cm.
5.2 Detection wavelength: 355 nm.
5.3 Sensitivity: 0.002 AUFS.
5.4 Column temperature: room temperature.
5.5 Flow rate: 1.0 mL/min.
5.6 injection volume: 10 μL.
5.7 Mobile phase: acetonitrile/0.01 mol/L sodium dihydrogen phosphate solution (pH 2.5 with 30% (v/v) nitric acid solution) 35:65
(V/V) Degassed with ultrasound for 10 min before use.
6 Operation method
6.1 Determination of the sample: Weigh 5.00 g (±0.01 g) of chopped meat (<5 mm) and place it in a 50-mL Erlenmeyer flask. Add 5% perchloric acid 25.0 mL and shake on the shaker for 10 min. , Move into a centrifuge tube and centrifuge at 2000 r/min
In 3 min, the supernatant was filtered through a 0.45 μm filter and 10 μL of the solution was sampled. The peak height was recorded and the content was determined from the working curve.
6.2 Working curve: Weigh 7 pieces of minced meat samples, 5.00 g (±0.01 g) each, and add 0, 25, 50, 100, 150, 200, 250 μL of standard solution (containing oxytetracycline, respectively). Tetracyclines are 0, 2.5, 5.0, 10.0, 15.0 each
, 20.0, 25.0 μg, containing chlortetracycline 0, 5.0, 10.0, 20.0, 30.0, 40.0, 50.0 μg), operating according to 6.1 method, taking the peak height as the ordinate and the antibiotic content as the abscissa, drawing the working curve.
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