GB/T 13531.7-2018 English PDF (GBT13531.7-2018)

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GB/T 13531.7-2018: General methods on determination of cosmetics -- Determination of refractive index
GB/T 13531.7-2018
General methods on determination of cosmetics-Determination of refractive index
ICS 71.100.70
Y42
National Standards of People's Republic of China
Cosmetics - General test methods - Determination of refractive index
Published on.2018-02-06
2018-09-01 implementation
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
China National Standardization Administration issued
Foreword
GB/T 13531 "General Methods for Testing Cosmetics" is divided into the following sections.
---GB/T 13531.1 "Measurement of pH value of general inspection methods for cosmetics";
---GB/T 13531.3 "Determination of turbidity of general inspection methods for cosmetics";
---GB/T 13531.4 "Determination of the relative density of general inspection methods for cosmetics";
---GB/T 13531.6 "General determination of the method of determination of granularity (fineness) of cosmetics";
---GB/T 13531.7 "Determination of refractive index of general inspection methods for cosmetics".
This part is part 7 of GB/T 13531.
This part is drafted in accordance with the rules given in GB/T 1.1-2009.
This part was proposed by the China National Light Industry Council.
This part is under the jurisdiction of the National Spice and Fragrance Cosmetics Standardization Technical Committee (SAC/TC257).
This section was drafted. Shanghai Daily Chemical Industry Research Institute, Austria Anton Paar (China) Co., Ltd., Guangdong Bawei Biotechnology
Co., Ltd., Polaiya Cosmetics Co., Ltd., Pediatric Maternal and Child Products (Shanghai) Co., Ltd., Amore Cosmetics (Shanghai) Co., Ltd.
the company.
The main drafters of this section. Wang Yanping, Shen Min, Chen Yu, Leng Qunying, Jiang Ligang, Dai Weining, Liu Ruixue.
Cosmetics - General test methods - Determination of refractive index
1 Scope
This part of GB/T 13531 specifies the method for determining the refractive index of liquid and semi-solid cosmetics.
The first method of this part applies to the determination of the refractive index of transparent liquid cosmetics.
The second method of this part applies to the determination of the refractive index of liquid or semi-solid cosmetics.
2 Terms and definitions
The following terms and definitions apply to this document.
2.1 refractive index refractiveindex
The sine of the angle of incidence and the sine of the angle of refraction when light of a certain wavelength is incident from the air into a sample maintained at a constant temperature
Ratio.
Note. The wavelength is specified as (589.3 ± 0.3) nm, which corresponds to the D1 and D2 lines in the sodium spectrum.
3 First Fabe refractometer method
3.1 Principle
The Abbe refractometer measures the refractive index of a sample based on the principle of determining the critical angle based on the law of refraction. Directly measure the refraction angle or observe the total reflex
The critical line of the shot, the sample to be tested should maintain the state of isotropic and transparent.
3.2 Reagents
3.2.1 Unless otherwise stated, the reagents used were of analytical grade and the water was distilled water or water of equivalent purity.
3.2.2 Reference material, reagent for refractive index (RI), used to calibrate the refractometer, as follows.
a) distilled water, the refractive index at 20 ° C is 1.3330;
b) for isopropyl toluene, the refractive index at 20 ° C is 1.4906;
c) benzyl benzoate, the refractive index at 20 ° C is 1.5685;
d) 1-bromonaphthalene having a refractive index of 1.6585 at 20 °C.
3.3 Instruments
3.3.1 Abbe refractometer. It can directly read the refractive index in the range of 1.3000~1.7200 with a precision of ±0.0002.
3.3.2 Constant temperature water bath or device with constant temperature. ensure that the circulating water flow can be kept at the specified test temperature ± 0.2 °C when passing through the Abbe refractometer.
3.3.3 Light source. sodium light. When using diffuse light or electric light as the refractometer source, an achromatic compensation prism should be used.
3.3.4 Glass sheet (optional), known as the refractive index.
3.4 Steps
3.4.1 Sample preparation
The sample temperature is brought close to the measured temperature.
3.4.2 Calibration of Abbe Refractometer
3.4.2.1 Correct the Abbe refractometer (3.3.1) by measuring the refractive index of the reference material (3.2.2).
Note. Some instruments can be adjusted directly with the glass piece (3.3.4) according to the instructions provided by the instrument manufacturer.
3.4.2.2 Keep the temperature of the Abbe refractometer (3.3.1) constant at the specified measurement temperature.
During the measurement, the temperature fluctuation range should be within ± 0.2 ° C of the specified temperature.
Note. The reference temperature is 20 °C. See the product standard for specific temperatures.
3.4.3 Determination steps
3.4.3.1 Clean the surface of the prism before the measurement. Use the absorbent cotton to pick up the volatile solvent ethanol and ether and rub it gently. After the solvent is evaporated, the prism is finished.
Fully dry.
3.4.3.2 Connect the constant temperature water bath to the prism and adjust the bath temperature to maintain the prism temperature at the desired operating temperature.
3.4.3.3 Correct the refractometer reading as specified in 3.4.2. Repeat 3.4.3.1 and 3.4.3.2 operations.
3.4.3.4 Add a few drops of the sample to the lower prism with a dropper, quickly close the prism and tighten. The sample should be evenly filled with field of view without bubbles. Static
Set a few minutes until the prism temperature returns to the desired operating temperature.
3.4.3.5 Align the light source and observe it by the eyepiece. Rotate the compensator spiral to make the boundary between the light and the dark clear, and the color disappears completely. Rotate again
The scale pointer is spiraled so that the dividing line passes just the focus of the "╳" line on the objective lens.
3.4.3.6 Accurately read the refractive index on the scale to four decimal places.
3.5 result representation
The results of the measurements are expressed as the average of the two measurements, and the results are retained to three decimal places.
3.6 precision
The absolute error of two parallel tests is not more than 0.002.
4 second method automatic refractometer method
4.1 Principle
The refractive index of the sample measured by the automatic refractometer is based on the determination of the critical angle of total reflection.
The LED source emits light from a variety of different angles to the prism surface in contact with the sample. Due to the different refractive indices of the sample and the prism, the light
Partial refraction and reflection, or total reflection (α-critical) occurs.
Using a high-resolution sensor array to measure the intensity of the reflected light, the critical angle of total reflection can be calculated, and then it can be determined according to the critical angle.
The refractive index (RI) of the sample.
4.2 Instruments
4.2.1 Automatic refractometer. has automatic temperature control functions, such as Abbemat200, or equivalent.
4.2.2 The accuracy of the automatic refractometer is as follows.
a) Temperature. ±0.05 °C (10 °C ~ 60 °C);
b) Refractive index. ±0.0001 (1.30nD~1.72nD).
4.3 steps
4.3.1 Calibrate the instrument according to the requirements of the instrument manual before testing.
4.3.2 Set the temperature of the instrument to the temperature to be measured.
4.3.3 Inject the sample into the clean and dry measuring cell with a dropper. The sample must pass through the prism.
4.3.4 Record the value when the instrument shows a stable refractive index.
4.3.5 After the measurement is finished, wipe the prism with a dust-free test paper or lens tissue.
4.4 Results representation
The results of the measurements are expressed as the average of the two measurements, and the results are retained to four decimal places.
4.5 Precision
The absolute error of the results of two parallel tests is not more than 0.0005.