GB 5009.169-2016National food safety standard - Determination of taurine in foods (English PDF)

3.1 Reagents

3.1.1 Metaphosphoric acid.

3.1.2 Trisodium citrate.

3.1.7 Potassium hydroxide.

3.1.8 O-phthalaldehyde (OPA).

3.1.9 2-mercaptoethanol.

3.1.10 Polyoxyethylene lauric acid ether (Brij-35).

3.2 Reagent preparation

3.2.1 Metaphosphoric acid solution (30 g/L)

WEIGH 30.0 g of metaphosphoric acid (3.1.1); USE water to dissolve it and

MAKE its volume reach to 1000 mL.

3.2.2 Trisodium citrate solution

WEIGH 19.6 g of trisodium citrate (3.1.2); ADD 950 mL of water to dissolve it;

ADD 1 mL of phenol (3.1.3); USE nitric acid (3.1.4) to adjust the pH to 3.10 ~

3.25; MAKE it pass through a 0.45 µm microfiltration membrane for filtration.

3.2.3 Post-column fluorescence derivative solution (o-phthalaldehyde

solution)

3.2.4 Precipitant

3.2.4.1 Precipitant I. WEIGH 15.0 g of potassium ferrocyanide (3.1.11); USE

water to dissolve it and MAKE the volume reach to 100 mL. This precipitant is

stable at room temperature for 3 months.

3.4 Standard solution preparation

3.4.1 Taurine standard stock solution (1 mg/mL)

Accurately WEIGH 0.1000 g of taurine standard substance (3.3), USE water to

dissolve it and MAKE the volume reach to 100 mL.

4.1 High performance liquid chromatography. with a fluorescence detector.

4.2 Post-column reactor.

4.5 pH meter. accuracy 0.01.

4.6 Centrifuge. not less than 5000 r/min.

4.7 Microporous membrane. 0.45 µm.

4.8 Balance. sensitivity of 0.0001 g.

5.1 Sample preparation

Accurately WEIGH 1 g ~ 5 g (accurate to 0.01 g) of solid sample in the conical

flask; ADD 20 mL of about 40 °C warm water; SHAKE it uniformly to dissolve

the sample; PLACE it in the ultrasonic oscillator for ultrasonic extraction for 10

min. ADD another 50 mL of metaphosphoric acid solution (3.2.1); SHAKE it

uniformly.

5.2 Instrument reference conditions

5.2.1 Column. Sodium ion amino acid analysis column (25 cm × 4.6 mm) or the

equivalent.

5.2.2 Mobile phase. Trisodium citrate solution (3.2.2).

5.2.3 Mobile phase flow rate. 0.4 mL/min.

5.2.4 Fluorescence derivative solvent flow rate. 0.3 mL/min.

5.2.5 Column temperature. 55 °C.

5.3 Production of standard curve

Respectively INJECT the standard series working solution into the high

performance liquid chromatograph; DETERMINE the corresponding

chromatographic peak height or peak area; USE the concentration of the

standard working solution as the abscissa AND the response value (peak area

or peak height) as the ordinate, to draw the standard curve.

5.4 Determination of sample solution

INJECT the sample solution into the high performance liquid chromatograph to

obtain the chromatographic peak height or peak area; OBTAIN the

concentration of taurine in the test solution based on the standard curve.

10.1 Reagents

10.1.1 Acetonitrile. chromatographic purity.

10.1.2 Glacial acetic acid.

10.1.7 Dansyl chloride (5-dimethylaminonaphthalene-1-sulfonyl chloride).

Chromatographic purity.

10.2 Reagent preparation

10.2.1 Hydrochloric acid solution (1 mol/L). ABSORB 9 mL of hydrochloric acid

(10.1.3); USE water to dilute it and MAKE the volume reach to 100 mL.

10.2.2 Sodium carbonate buffer (pH 9.5) (80 mmol/L).

10.2.3 Dansyl chloride solution (1.5 mg/mL). WEIGH 0.15 g of dansyl chloride

(10.1.7); USE acetonitrile (10.1.1) to dissolve it and MAKE the volume reach to

10.3 Standard substance

Purity >= 99%, CAS. 107-35-7.

10.4 Preparation of standard solution

10.4.1 Taurine standard stock solution (1 mg/mL)

Accurately WEIGH 0.1000 g of taurine standard substance (3.3); USE water to

dissolve it and MAKE the volume reach to 100 mL.

11.1 High performance liquid chromatograph. with a fluorescence detector or

an ultraviolet detector or diode array detector.

11.2 Vortex mixer.

11.3 Ultrasonic oscillator.

11.6 Microporous membrane. 0.45 µm.

11.7 Balance. sensitivity 0.0001 g and 0.001 g.

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