This standard specifies a rapid method for determining the unsaponifiable matter content of animal and vegetable fats and oils by three extractions with hexane. This standard applies to all fats and oils. It does not apply to waxes. Compared with the first part of the standard method, the results are less systematic, especially for fats and oils with high unsaponifiable matter content, such as marine animal fats and oils. GB/T 5535.2-1998 Determination of unsaponifiable matter in animal and vegetable fats and oils Part 2: Rapid method with hexane extraction GB/T5535.2-1998 Standard download decompression password: www.bzxz.net

GB/T5535.2—1998
This standard is formulated in accordance with the international standard IS03596-2:1988 "Animal and vegetable fats and oils-Determination of unsaponifiable matter Part 2: Hexane extraction rapid method". It is equivalent to the international standard in terms of technical content, and is compiled in accordance with the requirements of GB/T1.1-1993 "Guidelines for standardization work Unit 1: Rules for drafting and expressing standards Part 1: Basic provisions for standard compilation". This standard was proposed by the Ministry of Domestic Trade of the People's Republic of China. The drafting unit of this standard is the Institute of Cereal Oil Chemistry of the Ministry of Domestic Trade. The main drafters of this standard are Hao Xicheng, Ying Shanhong and Liu Jing. ISO Foreword
ISO (International Organization for Standardization) is a worldwide federation composed of national standardization bodies (ISO member bodies). The work of international standards is usually carried out by ISO's technical committees. If each member body is interested in the standard project established by a technical committee, it has the right to participate in the work of the committee. Maintain close cooperation with ISO and the International Electrotechnical Commission (IEC). The draft international standard adopted by the technical committee must be submitted to the member bodies for approval before it is accepted by the ISO committee as an international standard. An international standard must be approved by at least 75% of the member bodies that voted before it can be approved as a formal ISO standard.
IS03596-2 was developed by the ISO/TC Technical Committee on Agri-food. The general title of ISO 3596 is "Animal and vegetable fats and oils-Determination of unsaponifiable matter" and it consists of the following parts:
Part 1: Ether extraction method (reference method)Part 2: Rapid method using hexane
Approved by the State Administration of Quality and Technical Supervision on May 8, 1998For implementation on December 1, 1998
1 Scope
GB/T 5535.2-1998
National Standard of the People's Republic of China
Animal and vegetable fats and oilsDetermination of unsaponifiable matterPart 2: Rapid method using hexane extractionGB/T5535.2—1998bzxz.net
eqvISo3596-2:1988
This standard specifies a rapid method for determining the unsaponifiable matter content of animal and vegetable fats and oils by three extractions with hexane.
This standard applies to all fats and oils. It is not applicable to waxes. Compared with Part 1 of the standard method, the results are less systematic, especially for fats and oils with high unsaponifiable matter content, such as marine animal fats and oils. Cited standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. At the time of publication of the standard, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest version of the following standards. GB/T15687—1995 Preparation of fat samples
3 Definitions
This standard adopts the following definitions.
Unsaponifiable matter: Under the operating conditions specified in this standard, all products of the sample after saponification with potassium hydroxide are extracted with hexane, and the solvent is evaporated and the residue is dried. It is expressed as a percentage by mass. 4 Principle
Fats and potassium hydroxide ethanol solution are saponified under boiling and reflux, and unsaponifiable matter is extracted from the soap solution with hexane or petroleum ether. The solvent is evaporated and the residue is dried and weighed. 5 Reagents
The reagents listed in this standard are all analytically pure, and the water is distilled water. 5.1 n-hexane (Liao Q/LHS02) or 30-60℃ petroleum ether (HG3-1003) distilled in the 40-60℃ section. Both solvents must not contain impurities.
5.295% ethanol (GB679), prepared into a 10% aqueous solution. 5.3 Phenol (GB10729) indicator solution: 10g/L 95% ethanol solution. 5.4 Potassium hydroxide (GB2303) ethanol solution: c(KOH) ~ 1 mol/L. Dissolve 60g potassium hydroxide in 50mL water, then dilute to 1000mL with 95% (V/V) ethanol. The solution should be colorless or light yellow.
5.5 Potassium hydroxide standard solution: c(KOH) = 0.1 mol/L (in 95% ethanol). Approved by the State Administration of Quality and Technical Supervision on May 8, 1998, implemented on December 1, 1998
GB/T5535.2-1998
The exact concentration of the solution must be known before use and should be calibrated. Use the solution prepared at least five days ago, transfer the clear solution to a brown glass bottle for storage, and seal it with a rubber stopper. The solution should be colorless or light yellow. 6 Apparatus
a) Round bottom flask: 250mL round bottom flask with standard ground mouth; b) Reflux condenser: Matching the ground mouth of flask [a]; c) 250mL separatory funnel, preferably with a polytetrafluoroethylene piston and stopper; d) Water bath;
e) Electric oven or vacuum drying apparatus that can maintain (103±2)℃, such as rotary evaporator and other similar apparatus.
7 Sample preparation
Prepare the sample according to GB/T15687.
8 Analysis steps
8.1 Sample
Weigh about 5g of sample (accurate to 0.01g) and put it into a 250mL flask. 8.2 Saponification
Add 50mL potassium hydroxide solution (5.4) and some zeolite. After the flask is connected to the reflux condenser [Chapter 6 b)], boil and reflux for 1h. Stop heating, add 50 mL of water from the top of the reflux tube and shake. 8.3 Extraction of unsaponifiable matter
After cooling, transfer the solution to a 250 mL separatory funnel [Chapter 6, c]], rinse the flask and zeolite with 50 mL of hexane (5.1) several times, and pour the rinse solution into the separatory funnel. Cover the stopper, shake vigorously for 1 minute, invert the separatory funnel, and carefully open the piston to release the internal pressure intermittently. After standing and separating the layers, try to put the lower layer of saponified liquid into the second separatory funnel.
Note: If an emulsion is formed, add a small amount of ethanol or concentrated potassium hydroxide or sodium chloride to break the emulsion. Use the same method to extract the saponified liquid twice more with 50 mL of hexane each time. Collect the three hexane extracts in the same separatory funnel.
8.4 Washing of hexane extracts
Wash the mixed extracts three times with 25 mL of ethanol solution (5.2) and shake vigorously. After washing, discard the ethanol-water solution. Each time, 2 mL of the washing solution is discharged, and the separatory funnel is rotated on its axis. Wait for several minutes to allow the remaining ethanol-water layer to collect further. Discard the collection and close the piston when the hexane solution reaches the piston hole.
Continue washing with ethanol solution until the washing solution no longer appears pink after adding a drop of phenol solution (5.3).
8.5 Evaporation of solvent
Transfer a quantitative amount of the hexane solution (previously dried in an oven at 130±2°C [Chapter 6e)] to a 250 mL flask [Chapter 6a]] little by little through the upper opening of the separatory funnel (previously dried in an oven at 130±2°C [Chapter 6e) and weighed to the nearest 0.1 mg after cooling). Recover the solvent by distillation in a boiling water bath [Chapter 6d]]. 8.6 Drying and determination of residue
Place the flask in an almost horizontal position and dry the residue in an oven at (103±2)℃ for 15 min. Cool in a desiccator and weigh to the nearest 0.1 mg. Repeat the drying process until the mass of the residue weighed twice does not exceed 1.5 mg. If the mass is not constant after three dryings, the unsaponifiable matter may be contaminated and the determination must be repeated. Approved by the State Administration of Quality and Technical Supervision on May 8, 1998, and implemented on December 1, 1998
GB/T 5535.2—1998
When the mass of the residue is corrected by the content of free fatty acids, dissolve the weighed residue in 4 ml of ether and then add 20 ml of ethanol that has been neutralized to a light pink color with the phenolic acid indicator (5.3). Titrate with a potassium hydroxide ethanol standard solution (5.5) to the same final color. 8.7 Number of determinations
The same sample shall be determined twice.
8.8 Blank test
A blank test is required, using the same steps and the same amount of all reagents, but without adding the sample. If the residue exceeds 1.5 mg, the technical methods and reagents need to be improved. 9
Result calculation
The unsaponifiable matter content is expressed as a percentage of the mass of the sample. Unsaponifiable matter (%) = \-mm×100
Where: mo
10Test report
The mass of the sample, g;
The mass of the residue, g;
The mass of the blank residue, g;
The mass of free fatty acids, equal to 0.28Vc, g; The volume of the standard potassium hydroxide ethanol solution, mL; The accurate concentration of the potassium hydroxide ethanol standard solution (5.5), mo1/L. (1)
The test report shall specify the method of use of the results obtained. It shall also state all operating details not specified in this standard. And any details that may affect the results. The test report shall include complete information required for sample identification. Approved by the State Administration of Quality and Technical Supervision on May 8, 1998 and implemented on December 1, 1998
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