GB/T 5009.49-2008Method for analysis of hygienic standard of fermented alcoholic beverages and their integrated alcoholic beverages (English PDF)

4.1 Total sulfur dioxide

4.1.1 Oxidation

4.1.1.1 Principle

At low temperatures, the samples with an excess of free sulfur dioxide reaction with hydrogen peroxide to form sulfuric acid, with an alkali generating titrate

Sulfuric acid, whereby the content of the sample can be obtained free of sulfur dioxide. Under heating in the sample combined sulfur dioxide is released, too

Hydrogen peroxide redox reaction by titration with sodium hydroxide standard solution of sulfuric acid generated, the sample can be obtained sulfur-containing combination the amount. In conjunction with the free sulfur dioxide measured values are added, the total content of the sample obtained sulfur dioxide.

4.1.1.2 Reagents

4.1.1.2.1 hydrogen peroxide (H2O2)

AR.

4.1.1.2.2 phosphoric acid (H3PO4)

AR.

4.1.1.2.3 sodium hydroxide (NaOH)

AR.

4.1.1.2.4 methyl red (C15H15N3O2)

indicator.

4.1.1.2.5 methylene blue (C16H18CIN3S · 3H2O)

indicator.

4.1.1.2.6

hydrogen peroxide solution (0.3%). lessons 1mL30% hydrogen peroxide (stored in the refrigerator after opening), diluted with water to 100mL.

Formulated the day of use.

4.1.1.2.7 phosphoric acid solution (25%)

amount of 295mL85% phosphoric acid, diluted with water to 1000mL.

4.1.1.2.8

standard titration solution of sodium hydroxide [Ba (NaOH) = 0.01mol/L]. prepared according to GB/T 5009.1-2003 Appendix B

And calibration. Stored in the bottle soda lime tube fitted with rubber stopper weekly reconfiguration.

4.1.1.2.9

methyl red - methylene blue mixed indicator solution.

Solution I. Weigh 0.1g methylene blue, was dissolved in ethanol (95%), diluted to 100mL with ethanol (95%).

Solution II. Weigh 0.1g methyl red, soluble in ethanol (95%), diluted to 100mL with ethanol (95%).