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GB/T 5535.2-2008 (GB/T5535.2-2008)

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GB/T 5535.2-2008
Animal and vegetable fats and oils.Determination of unsaponifiable matter.Part 2. Method using hexane extraction
ICS 67.200.10
National Standards of People's Republic of China
GB/T 555.2-2008/ISO 18609..2000
Replaces GB/T 555.2-1998
Determination of unsaponifiable matter of animal and vegetable fats
Part 2. Hexane extraction method
(ISO 1809..2000, IDT)
2008-08-22 released
Implemented in.2008-12-12-01
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
Published by China National Standardization Administration
GB/T 5535 "Determination of unsaponifiable matter of animal and vegetable fats" is divided into two parts.
--- Part 1. Ether extraction method;
--- Part 2. Hexane extraction method.
This part is the second part of GB/T 5535.
This section is equivalent to ISO 1809..2000 "Hexane extraction method for determination of unsaponifiable matter of animal and vegetable fats and oils" (English version).
For ease of use, this section has made the following editorial changes to ISO 18609..2000.
--- Delete the foreword of international standards;
--- Change "this International Standard" to "this section";
--- Replace the comma "," as the decimal point in the original text with the decimal point ".";
--- Use GB/T 15687 to replace ISO 661 in the original international standard.
This section replaces GB/T 555.2-1998 "Determination of unsaponifiable matter of animal and vegetable oils and fats since the implementation date. Part 2. Hexane extraction
Quick Act.
Appendix A to this section is an informative appendix.
This section is proposed by the State Grain Administration.
This section is under the jurisdiction of the National Grain and Oil Standardization Technical Committee.
This section is responsible for drafting. Wuhan Institute of Technology.
The main drafters of this section. Gong Zhiyong, He Dongping, Zhang Shihong, Yao Li, and Liu Lina.
The previous versions of the standards replaced by this section are.
--- GB/T 555.2-1998.
GB/T 555.2-2008/ISO 18609..2000
Determination of unsaponifiable matter of animal and vegetable fats
Part 2. Hexane extraction method
1 Scope
This part of GB/T 5535 specifies the method for three times extraction of hexane to determine the content of unsaponifiable matter in animal and vegetable oils and fats.
This section applies to all greases, not waxes.
Warning. Compared with the method in GB/T 555.35.1, the determination result of this method is lower.
2 Normative references
The clauses in the following documents become the clauses of this section after being quoted in this part of GB/T 5535. For dated references,
All subsequent amendments (excluding errata) or revisions are not applicable to this section, however, it is encouraged to reach agreement based on this section
The parties studied whether the latest versions of these documents could be used. For undated references, the latest edition applies to this section.
GB/T 15867 Preparation of grease samples (GB/T 15687-1995, eqv ISO 661. 1989)
3 Terms and definitions
The following terms and definitions apply to this part of GB/T 5535.
The product saponified with potassium hydroxide is extracted with hexane, and all substances are not volatile under prescribed conditions.
Note. Unsaponifiable substances include fatty substances in nature, such as sterols, hydrocarbons, alcohols, aliphatic and terpene alcohols, and non-volatile when extracted with solvents at 103 ° C.
(Such as mineral oil) foreign organic matter.
4 Principle
Fatty oil and potassium hydroxide ethanol solution are saponified under boiling reflux condition, and unsaponifiable matter is extracted from the saponified solution with hexane or petroleum ether.
The solvent was evaporated and the residue was dried and weighed.
5 Reagents
The reagents used in this section are of analytical grade, and the water is distilled water, deionized water, or water of equivalent purity.
5.1 N-hexane or petroleum ether with a boiling range of 40 ° C to 60 ° C. The bromine value is less than 1 and must not contain impurities.
5.2 10% (volume fraction) aqueous ethanol solution.
5.3 Phenolphthalein indicator. 95% (volume fraction) ethanol solution of 10g/L.
5.4 Potassium hydroxide-ethanol solution. 犮 (KOH) ≈ 1mol/L. Dissolve 60 g of potassium hydroxide in 50 mL of water, then dilute with 95% ethanol
Release to 1000mL, the solution should be colorless or light yellow.
6 Instruments
Laboratory commonly used instruments, especially the following.
6.1 Round-bottomed flask. 250mL round-bottomed flask with standard grinding mouth.
6.2 Reflux condensing tube. It has a grinding mouth matching the flask (6.1).
6.3 250mL separatory funnel. Use PTFE stoppers and stoppers.
GB/T 555.2-2008/ISO 18609..2000
6.4 Water bath.
6.5 Electric oven. It can maintain 103 ° C ± 2 ° C. Or vacuum dryers, such as rotary evaporators and other similar equipment.
扦 sample
For example, it is not the content of this part, ISO 5555 is recommended.
The samples received by the laboratory should be representative and should not be damaged or altered during transportation and storage.
8 Sample preparation
Implemented according to GB/T 15687.
9 Analysis steps
9.1 Weighing
Weigh about 5g sample (Chapter 8), accurate to 0.01g, and put it into a 250mL flask (6.1).
9.2 Saponification
Add 50 mL of potassium hydroxide solution (5.4) and some zeolite. After the flask was connected to the reflux condenser (6.2), it was boiled and refluxed for 1 h. stop
Heat, add 50mL of water from the top of the reflux tube and shake.
9.3 Extraction of unsaponifiable matter
After cooling, transfer the saponification solution to a 250 mL separatory funnel (6.3), and wash the flask and zeolite with 50 mL of hexane (5.1) several times.
Pour into a separatory funnel. Cover the cock, shake it vigorously for 1 min, invert the separatory funnel, and carefully open the cock to release the internal pressure intermittently. Stand-up
Funnel. After the solution is separated, try to put the lower saponification solution into the second separating funnel. If an emulsion is formed, add a small amount of ethanol or concentrated
Demulsification with potassium hydroxide or sodium chloride.
In the same way, the saponification solution was extracted twice with 50 mL of hexane each time. The three hexane extracts were collected in the same separatory funnel.
9.4 Washing of hexane extract
Wash the extract three times with ethanol solution (5.2), each time using 25mL, and shake vigorously. After washing, discard the ethanol aqueous solution, and discard each time.
After removing the washing liquid, keep 2 ml of washing liquid remaining in the separating funnel, and then rotate the separating funnel along its axis. Let it sit for a few minutes, leaving the rest
The aqueous ethanol phase was further separated and discarded. The cock was closed when the hexane solution reached the cock channel. Continue washing with ethanol solution until
After adding 1 drop of phenolphthalein solution (5.3) to the washing solution, it will not appear pink.
9.5 Evaporated solvents
Carefully transfer the hexane solution through the upper mouth of the separatory funnel to a 250 mL flask (6.1) accurately weighed to 0.1 mg. Flask
It should be dried and cooled in a 103 ° C oven (6.5) before weighing. Evaporate the solvent in a boiling water bath (6.4).
9.6 Drying and determination of residues
9.6.1 Place the flask horizontally in an oven (6.5) at 103 ° C and dry the residue for 15 min. Cool in a desiccator and weigh accurately to
You can also use a vacuum dryer (6.5) to dry. Under the maximum vacuum, steam in a boiling water bath for 15 minutes, then cool to room temperature.
Dry the surface with water and weigh accurately to 0.1 mg.
Repeat the drying process until the weight difference between the two weighings does not exceed 1.5 mg. If it is not constant after three dryings, the unsaponifiable matter may
Can be contaminated and need to be re-measured.
9.6.2 If calibration with free fatty acids is required, the residue after weighing is dissolved in 4 mL of n-hexane (5.1), and then 20 mL is added.
Neutralize the ethanol in advance to make the phenolphthalein indicator (5.3) pale pink. Calibrate with 0.1mol/L standard potassium hydroxide-ethanol standard solution to the end
point. Calculate the mass of free fatty acids with oleic acid and use this to correct the mass of residues (Chapter 10).
9.7 Measurement times
Two determinations are required for the same sample.
GB/T 555.2-2008/ISO 18609..2000
9.8 Blank experiment
A blank experiment is required, using the same steps and the same amount of all reagents, but without adding samples. If the residue exceeds 1.5 mg,
Check the assay method and reagents.
10 Calculation of results
The unsaponifiable content of the sample is calculated according to formula (1).
100 (1)
In the formula.
X --- the content of unsaponifiable matter in the sample, in terms of mass fraction,%;
among them.
犞 --- the volume of standard potassium hydroxide-ethanol solution used for titration, the unit is milliliter (mL);
犮 --- The exact concentration of potassium hydroxide-ethanol standard solution, the unit is mole per liter (mol/L).
The arithmetic mean of the two measurements was used as the measurement result.
11 precision
Appendix A summarizes the interlaboratory testing of the precision of this method. The values obtained from these tests may not apply to other concentrates.
Degree range and other test objects.
12 test report
The test report must specify the matters.
--- All relevant information needed to test the sample;
--- If the sampling method is known, indicate;
--- The inspection methods and reference standards used;
--- Details not specified in this section or considered optional, and all operational details that may affect the results;
---The measurement results. If repeatability tests have been performed, the final results are listed.
GB/T 555.2-2008/ISO 18609..2000
Appendix A
(Informative appendix)
Joint experimental results
A. 1 participants
14 laboratories in six different countries (France, Germany, Hungary, Malaysia, Netherlands, UK) participated in the
Collaborative research organized by the Heart Institute.
A. 2 samples
There are three samples provided.
--- Sample A. Sunflower seed crude oil;
--- Sample B. Palm oil;
--- Sample C. Crude butter.
A. 3 results
Table A. 1. Table A. 2. Table A. 3 are the experimental results of sample A, sample B, and sample C, Table A. 4 lists the statistical scores of each sample
Analysis results.
According to Cochran and Dixon tests, the results of the experiments in Labs 6 and 9 were removed from Sample A and Labs 11
The experimental results (based on the Dixon test) exclude the data of sample C and the data of sample B are valid.
The average value of the unsaponifiable matter of the three experimental samples ranged from 0.15% to 0.58% (mass fraction).
The repeatability limit is 0.06% (mass fraction), and the repeatability coefficient of variation is between 3.6% and 10.5%.
The reproducibility limit is 0.18% (mass fraction), and the reproducibility variation coefficient is between 9% and 36%.
Table A. 1 Sample A. Sunflower seed crude oil
Laboratory results 1 /% (mass fraction) Results 2 /% (mass fraction)
2 0.541 0.545
3 0.51 0.52
4 0.62 0.58
5 0.57 0.63
6 0.78 0.61
7 0.54 0.51
8 0.64 0.62
9 0.89 0.89
10 0.54 0.557
11 0.62 0.64
12 0.6 0.63
13 0.68 0.68
14 0.56 0.52
Note. Based on the results of the Cochran test laboratory No. 6 (5%), according to the results of the Dixon test laboratory No. 9 (5%).
GB/T 555.2-2008/ISO 18609..2000
Table A. 2 Sample B. Palm oil
Laboratory results 1 /% (mass fraction) Results 2 /% (mass fraction)
1 0.35 0.33
2 0.2265 0.285
3 0.37 0.32
4 0.30 0.30
5 0.35 0.42
6 0.44 0.45
7 0.35 0.3
8 0.35 0.35
9 10.18 0.18
10 0.25 0.32
11 0.51 0.48
12 0.224 0.26
13 0.34 0.32
14 0.38 0.34
Table A. 3 Sample C. Beef crude oil
Laboratory results 1 /% (mass fraction) Results 2 /% (mass fraction)
10.16 0.18
2 0.1337 0. 106
3 0.18 0.17
4 0.115 0.14
5 0.22 0.223
6 0.09 0.12
7 0.09 0.11
8 0.2 0.21
9 0.04 0.03
10 0.113.18
11 0.40 0.41
12 0.113 0.14
13 0.23 0.22
14 0.16 0.19
Note. Based on the results of the Dixon test No. 11 laboratory, the results are removed (5%).
GB/T 555.2-2008/ISO 18609..2000
Table A. 4 Statistical analysis of test results
Parameter Crude sunflower oil sample A Crude palm oil sample B Crude butter sample C
Number of laboratories 14 14 14
Number of laboratories after invalid results 12 14 14 13
Mean /% (mass fraction) 0.58 0.33 0.115
Repeatability Standard Deviation (Sr) /% 0.02 0.03 0.02
Repeatability coefficient of variation /% 3.64 7.81 10.49
Reproducibility Standard Deviation (SR) /% 0.05 05.05 0.05
Reproducibility coefficient of variation /% 8.99 24.63 36.32
Reproducibility limit (R) /% 0.115 0.223 0.16
GB/T 555.2-2008/ISO 18609..2000
[1] GB/T 555.3 Determination of unsaponifiable matter in animal and vegetable oils and fats Part 1. Ether extraction method (GB/T 555.3-2008,
ISO 3596..2000, IDT).
[2] ISO 5555 Anonymous transfers-states-Sampling.
GB/T 555.2-2008/ISO 18609..2000
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.