GB/T 5515-1985 Grain and oilseed inspection - Determination of crude cellulose

This standard is applicable to the determination of crude cellulose in commercial grains. GB/T 5515-1985 Grain and oilseed inspection - Determination of crude cellulose GB/T5515-1985 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Inspection of grain and oil seedsMethods for determination of grude fiberThis standard applies to the determination of crude cellulose in commercial grains. Apparatus and equipment
1.1 Beaker: 500ml;
1.2 Gooch crucible: 30ml (after paving with asbestos, burn at 600℃ for 30min). 1.3 Glass wool suction filter tube: 1cm diameter;
1.4 Suction filter bottle;
1.5 Vacuum pump;
1.6 Measuring cylinder: 250ml;
1.7 Flat-bottom flask: 500ml;
1.8 Volumetric flask: 500ml;
1.9 Pipette: 5ml;
1.10 Universal electric furnace, high-temperature furnace;
Electric thermostatic box;
1.12 Dryer with color-changing silica gel;
1.13 Condenser, etc.
2 Reagentsbzxz.net
2.195% ethanol;
2.2 Ether;
2.3 Litmus paper;
GB/T5515-85
2.4 Acid-washed asbestos: first wash with 1.25% alkali solution until neutral, then wash with ethanol and ether three times in succession, and set aside after the ether evaporates;
2.51.25%0.255N sulfuric acid solution: use a pipette to measure 3.5ml of concentrated sulfuric acid with a specific gravity of 1.84, inject it into 500ml of water and adjust it to the accurate concentration after calibration;
2.61.25% (0.3125N) sodium hydroxide solution: take 7.0g of sodium hydroxide and dissolve it in 500ml of water. After calibration, adjust it to the accurate concentration.
3 Operation method
3.1 Weigh the sample: weigh 2-3g of the crushed sample and pour it into a 500ml beaker. If the fat content of the sample is high, the residue after fat extraction can be used as the sample, or the fat of the sample can be extracted with ether. 3.2 Acid treatment: add 200ml of 1.25% sulfuric acid solution boiled in a reflux device to the beaker containing the sample, record the liquid level in the beaker, cover the surface with blood, place on the electric furnace, boil within 1min, and continue to boil slowly for 30min. During the boiling process, add boiling water to keep the liquid level, turn the beaker frequently, leave the heat source at that time, wait for the precipitate to drop, use a glass wool suction tube to absorb the upper clear liquid, add 100-150ml boiling water to wash the precipitate immediately after absorbing it, and then absorb the clear liquid, and wash with boiling water until the precipitate is neutral when tested with litmus paper. 3.3 Alkali solution treatment: merge the glass wool in the suction tube into the precipitate, add 200ml of 1.25% alkali solution boiled in reflux device in advance, heat to a slight boil for 30min according to the acid solution treatment method, remove the beaker, let the precipitate drop, heat it to constant weight with Gooch filtration, transfer the precipitate into glass without loss with boiling water, and wash it to neutral. 3.4 Ethanol and ether treatment: first wash the precipitate with 20-25ml of ethanol heated to 50-60℃ for 3-4 times, then wash it with 20-25ml of
ether for 34 times, and finally drain the ether. 3.5 Drying and calcination: first dry the Gooch crucible and precipitate at 105℃ to constant weight, then send it into a 600℃ high temperature furnace and calcine for 30min, take it out, cool it, weigh it, and calcine for another 20min, until it is constant weight. Calculation of results
The dry basis content of crude cellulose is calculated according to the following formula: W1-W2
Crude cellulose (dry basis %)=
Sample weight, g;
W(100-M)
W1——weight after drying with precipitate, g;
W2——weight after burning with precipitate, g;M—moisture percentage, %.
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The allowable difference between the two test results shall not exceed 1% of the average value, and the average value shall be taken as the test result. The test result shall be taken to the first decimal place.
Additional remarks:
This standard is proposed by the Ministry of Commerce of the People's Republic of China. This standard is drafted by the Grain Storage and Transportation Bureau of the Ministry of Commerce. This standard was mainly drafted by Gao Xiuwu, Yang Haoran, Wu Yanxia and Lv Guifen. It was issued by the National Bureau of Standards on November 2, 1985 and implemented on July 1, 1986.
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