GB/T 14454.14-2008Fragrance/Flavor substances - Preparation of standard solution, test solution and indicator solution (English PDF)

Foreword

GB/T 14454, Fragrance/Flavor substances, consists of the following parts:

-- Part 1: Fragrance/Flavor substances - Preparation of test samples;

-- Part 2: Fragrance/Flavor substances - Method for valuation of odour;

-- Part 4: Fragrance/Flavor substances - Determination of refractive index;

-- Part 5: Fragrance/Flavor substances - Determination of optical rotation;

-- Part 6: Fragrance/Flavor substances - Quantitative evaluation of residue on evaporation;

-- Part 7: Fragrance/Flavor substances - Determination of freezing point;

-- Part 11: Fragrance/Flavor substances - Determination of content of phenols;

-- Part 12: Fragrance/Flavor substances - Method for determination of trace chlorinated compounds;

-- Part 13: Fragrance/Flavor substances - Determination of carbonyl value and carbonyl compounds content;

-- Part 14: Fragrance/Flavor substances - Preparation of standard solution, test solution and indicator solution;

-- Part 15: Oil of sassafras - Determination of safrole and isosafrole content - Gas chromatographic method on packed columns.

This Part is Part 14 of GB/T 14454.

This Part is a revision of GB/T 14454.14-1993 "Aromatics - Preparation of standard solution, test solution and indicator solution". The technical content is the same as GB/T 14454.14-1993; the compiling method is in accordance with GB/T 1.1-2000.

1 Scope

This Part of GB/T 14454 stipulates the preparation and calibration methods of standard solution, test solution and indicator solution for fragrance titration analysis.

This Part applies to the preparation of solutions of accurate concentration, as well as the preparation of test solution and indicator solution.

2 General provisions

2.1 The water that is used in this Part of GB/T 14454 shall be distilled water or water of equivalent purity unless other requirements are indicated.

2.2 The purity of the reagents that are used in this Part is at least analytically pure.

2.3 Weights of the analytical balance, burettes, volumetric flasks, and pipettes shall be regularly calibrated.

2.4 When calibrating the concentration of the standard solution, perform the parallel test for not less than eight times; two persons shall do four parallels.

The extreme difference between the four parallel determination results per person, and the ratio of the difference between the averages of the determination results of the two persons to the average value cannot be greater than 0.1% for the standard solution of 0.5 mol/L concentration, and cannot be greater than 0.5% for the standard solution of 0.1 mol/L concentration (that is, the difference of the fourth significant digit cannot be greater than 5).

2.5 The relative error between the concentration of the prepared standard solution and the specified concentration cannot be greater than 5%.

2.6 The standard solution for titration analysis shall be calibrated and used at normal temperature of 15 °C ~ 25 °C; the storage time cannot exceed three months in general.

3 Preparation and calibration of standard solution

Where: c(NaOH) -- the concentration of sodium hydroxide standard solution, in moles per liter (mol/L); m -- the mass of potassium hydrogen phthalate, in grams (g);

V1 -- the volume of sodium hydroxide standard solution for titration, in milliliters (mL);

V2 -- the volume of sodium hydroxide standard solution for blank test, in milliliters (mL);

0.2042 -- the mass of potassium hydrogen phthalate, in grams, that is equivalent to 1.00 mL of sodium hydroxide standard solution.

4 Preparation of test solution