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GB/T 14455.5-2008Fragrance/Flavor substances -- Determination of acid value or acid content (English PDF)

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Issued by

General Administration of Quality Supervision, Inspection and Quarantine

Level / Type

National · Recommended

Issue date

July 15, 2008

Implementation date

November 1, 2008

Scope

GB/T 14455.5-2008 (Fragrance/Flavor substances -- Determination of acid value or acid content) is available as an English-translated PDF.

GB/T 14455.5-2008 — This Part of GB/T 14455 stipulates the method for determining acid value or acid content of isolate and synthetic fragrances and acid value of essential oils. This Part does not apply to essential oils that contain more lactones.

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Document preview — GB/T 14455.5-2008

National Standard of the People's Republic of China

ICS: 71.100.60
Classification: Y 41

Issued by: General Administration of Quality Supervision, Inspection and Quarantine

Foreword...3
1 Scope...4
2 Normative references...4
3 Terms and definitions...4
4 Principle...4
5 Reagents...5
6 Instruments...5
7 Sample preparation...5
8 Operating procedures...6
9 Expression of results...7
10 Test report...8

Foreword

GB/T 14455, Fragrance/Flavor substances, consists of the following parts:

-- Part 1: Essential oils - Principles of nomenclature;

-- Part 3: Fragrance/Flavor substances - Evaluation of solubility (miscibility)

in ethanol

-- Part 5: Fragrance/Flavor substances - Determination of acid value or acid

content;

-- Part 6: Fragrance/Flavor substances - Determination of ester value or ester

content;

-- Part 7: Fragrance/Flavor substances - Determination of ester value after

acetylation and evaluation of free alcohols and total alcohols content.

This Part is Part 5 of GB/T 14455.

This Part modifies and adopts ISO 1242:1999, "Essential oils - Determination

of acid value". Compared with ISO 1242:1999, the main technical differences

are as follows:

-- Add the determination method and calculation formula of the acid value

and acid content of isolate and synthetic fragrance;

-- Remove the relevant provisions of sampling method and precision of ISO

1242:1999.

This Part is the combination and revision of GB/T 14455.5-1993, "Essential oils

- Determination of acid value" and GB/T 14457.4-1993 "Isolate and synthetic

aroma chemicals - Determination of acid value or acid content". Compared with

GB/T 14455.5-1993, GB/T 14457.4-1993, this Part mainly adds relevant

contents of the test report.

This Part was proposed by China National Light Industry Council.

This Part shall be under the jurisdiction of National Technical Committee 257

on Fragrance and Flavor Cosmetic of Standardization Administration of China.

This Part was drafted by Shanghai Research Institute of Fragrance & Flavor

Industry.

The drafters of this Part: Cao Yi, Xu Yi, Du Shixiang, Jin Qizhang.

Fragrance/Flavor substances -

Determination of acid value or acid content

1 Scope

This Part of GB/T 14455 stipulates the method for determining acid value or

acid content of isolate and synthetic fragrances and acid value of essential oils.

This Part does not apply to essential oils that contain more lactones.

2 Normative references

The terms in the following documents become the terms of this Part by

reference to this Part of GB/T 14455. For dated references, all subsequent

amendments (not including errata content) or revisions do not apply to this Part.

However, parties to agreements that are based on this Part are encouraged to

study whether the latest versions of these documents can be used. For undated

references, the latest edition applies to this Part.

GB/T 14454.1, Fragrance/Flavor substances - Preparation of test samples

(GB/T 14454.1-2008, ISO 356:1996, MOD)

GB/T 14454.14, Fragrance/Flavor substances - Preparation of standard

solution, test solution and indicator solution

GB/T 14455.6, Fragrance/Flavor substances - Determination of ester value

or ester content (GB/T 14455.6-2008, ISO 709:2001, MOD)

3 Terms and definitions

The following terms and definitions are applicable to this Part of GB/T 14455.

3.1 Acid value

The number of milligrams of potassium hydroxide that is required to neutralize

the free acid that is contained in 1 g of fragrance.

4 Principle

Use sodium hydroxide standard solution or potassium hydroxide ethanol

standard solution to neutralize the free acid.

8 Operating procedures

8.1 Isolate and synthetic fragrance

Weigh an appropriate amount of sample (accurate to 0.000 2 g) in a

saponification bottle or conical flask (6.1); add 20 mL of ethanol (5.1) and 3

drops of indicator (5.5); use sodium hydroxide standard solution (5.2 or 5.3) in

the burette (6.3 or 6.4) to titrate, until pink appears and maintains for 10 seconds

without fading; record the volume of used sodium hydroxide standard solution.

Note 1: If the ester value is to be determined, retain the saponification bottle

and the solution inside.

Note 2: When measuring the acid value, if the amount of sodium hydroxide

standard solution (5.2) exceeds 10 mL, reduce the sample and redo it,

or use sodium hydroxide standard solution (5.3), instead, for titration.

Note 3: When measuring the acid value of aldehyde products, pink appears as

the end point, because the active aldehyde groups are easily oxidized

to acid during the titration.

Note 4: For darker samples, more ethanol (5.1) can be added for dilution.

Note 5: When measuring the acid value of formate esters, such as geranyl

formate, benzyl formate, because such compounds are easily

hydrolyzed in the presence of alkali, which makes the acid value too

high; therefore, when measuring these samples, they shall be titrated

in ice water bath.

Note 6: When determining the acid value of salicylates, use 50% ethanol to

replace 95% ethanol, and use phenol red as an indicator.

8.2 Essential oil

8.2.1 Sample size

Weigh 2 g of the sample (accurate to 0.000 2 g).

Note: if the sample size is different from the above, it will be specified in the

relevant fragrance product standard.

8.2.2 Determination

Put the sample (8.2.1) into the saponification bottle or conical flask (6.1); add 5

mL of ethanol (5.1) and 3 drops of indicator (5.5); use the potassium hydroxide

ethanol standard solution (5.4) in the burette (6.4) to titrate the above liquid,

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 8 pages — is available in the English PDF.

Referenced standards

Normative references

GB/T 14455 · ISO 356 · ISO 709

Cited by

GB/T 14455.6-2008Fragrance/Flavor substances -- Determination of ester value or ester content

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