GB/T 14454.4-2008 English PDF (GBT14454.4-2008)

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GB/T 14454.4-2008: Fragrance/Flavor substances -- Determination of refractive index
GB/T 14454.4-2008
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.100.60
Y 41
Fragrance/flavor substances –
Determination of refractive index
(ISO 280.1998, Essential oils –
Determination of refractive index, MOD)
ISSUED ON. JULY 15, 2008
IMPLEMENTED ON. NOVEMBER 1, 2008
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Normative references ... 5 
3 Terms and definitions ... 5 
4 Principle ... 6 
5 Reagents ... 6 
6 Apparatus ... 6 
7 Operating procedures ... 6 
8 Determination ... 7 
9 Expression of results ... 7 
10 Test report ... 7 
Annex A (Normative) Operating procedure of abbe refractometer ... 9 
Foreword
GB/T 14454, Fragrance/Flavor substances - General test methods, comprises 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 4 of GB/T 14454.
This Part modifies and adopts ISO 280.1998, Fragrance/Flavor substances -
Determination of refractive index. Compared with ISO 280.1998, the major technical
differences of this Part are as follows.
-- the sampling method and repeatability of ISO 280.1998 are deleted;
-- Annex A is added.
This Part is a revision of GB/T 14454.4-1993, Fragrance/Flavor substances -
Determination of refractive index. Compared with GB/T 14454.4-1993, the major
changes of this Part are as follows.
-- the sampling method of GB/T 14454.4-1993 is deleted;
-- the conversion formula of refractive indexes at temperature t’ and t is added;
Fragrance/Flavor substances –
Determination of refractive index
1 Scope
This Part of GB/T 14454 specifies the method for the determination of refractive index
of fragrance/flavor substances.
This Part applies to the determination of refractive index of fragrance/flavor substances.
2 Normative references
The provisions in following documents become the provisions of this Part through
reference in this Part. For dated references, the subsequent amendments (excluding
corrigendum) or revisions do not apply to this Part. However, parties who reach an
agreement based on this Part are encouraged to study if the latest versions of these
documents are applicable. For undated references, the latest edition of the referenced
document applies.
GB/T 14454.1, Fragrance/Flavor substances - Preparation of test samples (GB/T
14454.1-2008, ISO 356.1996, MOD)
3 Terms and definitions
For the purposes of this Part of GB/T 14454, the following terms and definitions apply.
3.1
refractive index
ratio of the sine of the angle of incidence to the sine of the angle of refraction, when a
ray of light of defined wavelength passes from air into the essential oil kept at a
constant temperature
NOTE. The wavelength specified is 589.3 nm ± 0.3 nm corresponding to the D1 and D2 lines of
the sodium spectrum.
the temperature at which the measurements shall be made.
7.2 Regulation of the refractometer
7.2.1 Regulate the refractometer (6.1) by measuring the refractive index of the
standard products described in 5.2.1 to 5.2.4.
NOTE. Some instruments may be adjusted by means of a plate of glass (6.4), according to the
directions supplied by the manufacturer of the instrument.
7.2.2 Verify that the refractometer (6.1) is maintained at the temperature at which the
readings shall be made.
The temperature shall not differ from the reference temperature by more than ± 0.2°C
during the test.
The reference temperature is 20°C, except for those oils which are not liquid at this
temperature, in which case a temperature of 25°C or 30°C, depending on the melting
point of these essential oils, shall be used.
8 Determination
Place the test sample, prepared according to 7.1, in the refractometer. Wait until the
temperature is stable and make the measurements.
9 Expression of results
The refractive index at the specified temperature t, is given by the equation (1).
where is the reading taken at the working temperature t’ at which the
determination was actually made.
Express the result to four decimal places.
The permissible difference of the parallel test result is 0.000 2.
10 Test report
The test report shall state.
-- the sampling method used;