GB/T 14454.5-2008Fragrance/Flavor substances -- Determination of optical rotation (English PDF)

3.1 Optical rotation

Under the specified temperature conditions, when the polarized light whose wavelength is 589.3 nm ± 0.3 nm (equivalent to the D line of the natrium spectrum) passes through the fragrance whose thickness is 100 mm, the angle of rotation of the polarized light vibration plane, which is expressed in milliradians or degrees of angle.

Note: If it is measured at different thicknesses, the optical rotation shall be converted to a value of a thickness of 100 mm.

3.2 Optical rotation in solution, so-called

Specific rotation

5.4 Thermometer, the measuring range is 10 °C ~ 30 °C; the division scale is

0.2 or 0.1 °C.

5.5 Constant temperature controller, it is used to control the temperature of the sample at 20 °C ± 0.2 °C or other specified temperature.

6.1 Sample preparation

If it is necessary, dry the sample, in accordance with the provisions of GB/T

14454.1.

When determining the specific rotation (see 3.2), the solution of the fragrance product shall be prepared according to the concentration and solvent (4.2) that are specified in the standards that are related to fragrance products.

6.2 Determination

Turn on the light source (5.2) and wait for it to reach full brightness.

If necessary, the temperature of the sample (6.1) can be adjusted to 20 °C ±

1 °C or other specified temperature1; then, inject the sample into the appropriate polariscope tube (5.3) at the same temperature. Under constant temperature control, start the water circulation; keep the polariscope tube at a specified temperature (± 0.2 °C) during the test.

Fill the polariscope tube full of the sample; ensure that there are no bubbles in the tube.

Put the polariscope tube into the polarimeter (5.1); read the right-handed (+) or left-handed (-) optical rotation of the fragrance according to the scale on the instrument.

6.3 Number of determinations

For the same sample, measure at least three times.

The difference of three measured values shall not be larger than 1.4 milliradians (0.08 °). Take the average of the three readings as the measured result.

See Appendix A for the operating procedures of non-electronic polarimeters.

1 In general, the measurement shall be carried out at 20 °C. Exceptions are made in accordance with the provisions in the relevant fragrance product standards.

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