ISO-6866-1985.pdf
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1、International Standard $ 6866 0 a 4 4ig!B ,NTERNAT,ONAL ORGANlZATLON FOR STANDARDIZATION*MEXAYHAPOflHAfl OPrAHblSAUHfl fl0 CTAHAAPTbl3AUkIlWORGANlSATlON INTERNATIONALE DE NORMALISATION Animal feeding stuffs - Determination of free and total gossypol Aliments des animaux - Dosage du gossypol libre et
2、 du gossypol total First edition - 1985-11-15 i.ll- C 2 19 for compound feeding stuffs, it may be as much as 5 g. For the determination of total gossypol, the mass of the test portion should be between 0,5 and 5 g. NOTE - The mass of the test portion should be large enough to give the quantity of fr
3、ee gossypol indicated in 8.3.1.2 or the quantity of total gossypol indicated in 8.3.2.4 in each aliquot portion of the filtrate. 8.3 Determination 8.3.1 Determination of free gossypol 8.3.1.1 Transfer the test portion (8.2) to a 250 ml conical flask, the bottom of which has been covered with glass b
4、eads. Add, by means of a pipette, 50 ml of solvent A (5.21, stopper the flask and mix, using the tumbler mixer (6.11, for 1 h. Filter through a dry filter paper, collecting the filtrate in a 100 ml conical flask. During filtration, cover the funnel with a watch-glass. 8.3.1.2 Transfer, by means of a
5、 pipette, identical aliquot por- tions of the filtrate, containing 50 to 100 ug of gossypol, to each of two 25 ml volumetric flasks (6.3) (C and D). If necessary, make up to 10 ml with solvent A (5.2). 8.3.1.3 Make up the contents of flask C to volume with the 2-propanol/hexane mixture (5.1) and mix
6、. This solution will be used as the reference solution against which the test solution will be measured. 8.3.1.4 Transfer, by means of a pipette, 10 ml of solvent A (5.2) into each of two 25 ml volumetric flasks 1E and F). 8.3.1.5 Make up the contents of flask E to volume with the 2-propanoll hexane
7、 mixture (5.1) and mix. This solution will be used as the reference solution against which the blank test solution will be measured. 8.3.1.6 Add 2,0 ml of the aniline (5.4) to flasks D and F. Heat for 30 min on a boiling water-bath to develop the colour. 8.3.1.7 Cool to room temperature, make up to
8、volume with the 2-propanol/hexane mixture (5.11, mix and leave for 1 h. 8.3.1.8 Measure the absorbance of the blank test solution (flask F; 8.3.1.7) against the reference solution (flask E; 8.3.1.5). and the absorbance of the test solution (flask D; 8.3.1.7) against the reference solution (flask C;
9、8.3.1.3) using the spectrometer (6.2) at the wavelength of maximum absorb- ance (between 435 and 445 nm). 8.3.1.9 Subtract the absorbance of the blank test solution from that of the test solution to obtain the corrected ab- sorbance. 8.3.2 Determination of total gossypol 8.3.2.1 Transfer the test po
10、rtion (8.2) into a 50 ml volumetric flask and add 10 ml of solvent B (5.3). 8.3.2.2 Transfer 10 ml of solvent B (5.3) to a second 50 ml volumetric flask (6.3). 8.3.2.3 Heat the two flasks (8.3.2.1 and 8.3.2.2) for 30 min on a boiling water-bath. Cool to room temperature and make up to volume with th
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- ISO 6866 1985
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