GB/T 5534-1995 Determination of saponification value of animal and vegetable fats and oils

This standard specifies the determination method for the saponification value of animal and vegetable fats (excluding mineral acids). This standard does not apply to products containing inorganic acids unless the inorganic acid is determined separately. GB/T 5534-1995 Determination of saponification value of animal and vegetable fats GB/T5534-1995 Standard download decompression password: www.bzxz.net

GB/T5534-1995
National Standard of the People's Republic of China
Determination of saponification value of animal and vegetable oils and fats
Animal and vegetable oils and fats-Determination of saponification valueGB/T5534-1995
Replaces GB5534-85
This standard is equivalent to the international standard IS03657:1988 "Animal and vegetable oils and fats-Determination of saponification value". 1 Subject content and scope of application
This standard specifies the method for determining the saponification value of animal and vegetable oils and fats (excluding mineral acids). This standard is not applicable to products containing inorganic acids unless the inorganic acid is determined separately. 2 Reference standards
GB5524 Sampling and splitting method for inspection of vegetable oils and fats 3 Definition
The number of milligrams of potassium hydroxide required to saponify 1g of oil under specified conditions is the saponification value. 4 Principle
The sample and potassium hydroxide-ethanol solution are boiled together under reflux conditions, and then the excess potassium hydroxide is titrated with a standardized hydrochloric acid solution.
5 Reagents
All reagents must be of analytical grade, and the water used should be distilled water or water of equivalent purity. 5.1 Potassium hydroxide: About 0.5 mol/L potassium hydroxide is dissolved in 95% (V/V) ethanol. The solution should be colorless or light yellow. A stable colorless solution can be obtained by any of the following steps. a. Reflux 8g potassium hydroxide and 5g aluminum flakes in 1L ethanol for 1h and distill immediately. Dissolve the required amount of potassium hydroxide in the distillate, let it stand for several days, then pour out the clear supernatant to remove the potassium carbonate precipitate.
b. Add 4g aluminum tert-butylate to 1L ethanol, let it stand for several days, pour out the supernatant, dissolve the required amount of potassium hydroxide in it, let it stand for several days, then pour out the clear supernatant from the potassium carbonate precipitate. Store this solution in a brown or yellow glass bottle with a rubber stopper for later use. 5.2 Standard hydrochloric acid titration solution: c (HCI) = 0.5 mol/L. 5.3 Phenol 10 g/L dissolved in 95% (V/V) ethanol, or basic blue 6B 20 g/L dissolved in 95% (V/V) ethanol.
54 Boiling aid: glass beads or porcelain particles.
6 Instruments
Common laboratory instruments, especially the following instruments: Approved by the State Administration of Technical Supervision on August 17, 1995, implemented on January 1, 1996
GB/T5534-1995
6.1 Conical flask: 250 mL capacity, made of alkali-resistant glass, with ground mouth. 6.2 Reflux condenser: with a ground glass joint connected to the conical flask (6.1). 6.3 Heating device: such as a water bath, electric hot plate or other suitable instrument. Do not heat with open flame. 6.4 Burette: capacity 50mL, minimum scale 0.1mL. 6.5 Pipette: capacity 25mL. bzxZ.net
7 Sampling
Perform according to GB5524.
8 Steps
8.1 Sample quantity
Weigh 2g of the test sample (7) accurate to 0.005g into a conical flask (6.1). Note: Based on the saponification value of 170~200, the sample quantity to be measured is 2g. For other ranges of saponification values, the sample quantity will be changed based on the fact that about half of the potassium hydroxide-ethanol solution is neutralized. 8.2 Determination
8.2.1 Use a pipette (6.5) to add 25.0 mL of potassium hydroxide-ethanol solution (5.1) to the sample, and add some boiling aids (5.4). Connect the reflux condenser (6.2) to the conical flask (6.1), and place the conical flask on the heating device (6.3) to slowly boil, shaking from time to time. The oil should be kept boiling for 60 minutes. The oil that is difficult to saponify should be boiled for 2 hours.
8.2.2 Add 0.5~1 mL of phenolic acid indicator (5.3) to the hot solution, and titrate with a standard volume of hydrochloric acid solution until the pink color of the indicator disappears. If the saponified solution is dark, use 0.5~1 mL of basic blue 6B solution.
8.3 Blank test
Follow the steps in 8.2, without adding the sample, and then perform a blank test with 25.0 mL of potassium hydroxide-ethanol solution.
8.4 Number of determinations
The same sample is measured twice.
9 Result expression
Saponification value (Is) =. -V)×c×56.1
Wherein: Vo is the volume of the hydrochloric acid standard titration solution (5.2) consumed by the blank test, mL; Vi is the volume of the hydrochloric acid standard titration solution (5.2) consumed by the sample, mL; C is the actual concentration of the hydrochloric acid standard titration solution (5.2), mol/L; m is the mass of the sample (8.1), g.
If the repeatability (10) requirement is met, take the arithmetic mean of the two determinations as the result. The result is rounded to one decimal place.
10 Repeatability
The difference between the two determinations of the same sample made by the same analyst using the same instrument, either successively or simultaneously, should not exceed 0.5% (relative) of its arithmetic mean. Approved by the State Administration of Technical Supervision on August 17, 1995, and implemented on January 1, 1996
GB/T5534-1995
11 Test report
The test report shall indicate the method of use, the results obtained, and all operating details that are not specified in this standard or are optional, as well as details of various conditions that may affect the results. Approved by the State Administration of Technical Supervision on August 17, 1995, and implemented on January 1, 1996
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