GB 1886.170-2016Food safety national standard -- Food additive - 5-guanylate disodium (English PDF)

2.1 Chemical name

5'-guanylate disodium

2.2 Structural formula

2.3 Molecular formula

C10H12N5Na2O8P · nH2O

2.4 Relative molecular mass

407.18 (according to 2011 international relative atomic mass, on anhydrous basis)

3.1 Sensory requirements

Spectrophotometer.

A.3.2 Analytical procedures

WEIGH 1 g of sample (accurate to 0.0001 g); dissolve in 20 mL of water; shake well. PLACE the above sample solution into a 1 cm cuvette; USE water as a blank control; USE a spectrophotometer to, at 430 nm, determine the light transmittance of the sample solution; RECORD the reading.

The test result is based on the arithmetic mean of parallel determination results.

The absolute difference between the two independent determination results, obtained under repeated conditions, shall not exceed 0.5% of the arithmetic mean.

A.4 Determination of pH (5% aqueous solution)

A.4.1 Instruments and equipment

Acidimeter.

A.4.2 Analytical procedures

WEIGH 1 g of sample (accurate to 0.0001 g); dissolve in 20 mL of water; USE an acidimeter to determine the pH of the above sample solution.

The test result is based on the arithmetic mean of parallel determination results.

The absolute difference between the two independent determination results, obtained under repeated conditions, shall not exceed 0.2.

A.5 Determination of other nucleotides

A.5.1 Reagents and materials

A.5.1.1 Developing solution: tert-butanol+saturated ammonium sulfate+0.025

mol/L aqueous ammonia=3+160+40.

A.5.1.2 Chromatographic filter paper.

A.5.2 Instruments and equipment

A.5.2.1 UV analyzer.

A.5.2.2 Microinjector.

A.5.3 Analytical procedures

WEIGH 1.0 g of sample; ADD water to dissolve and dilute to 100 mL. USE a chromatographic filter paper for application of 10.0 µL of sample; SPREAD

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