| 摘要 |
Method for determining the lysine content and the total protein content of a protein-containing sample, said method comprising pretreating the sample by hydrolysis, adding an internal standard, and derivatising the amino acids included in the sample, whereupon the pretreated product is analysed by reversed-phase HPLC separation and by integration of the chromatogram obtained. What characterises the method is a) that the derivatisation is carried out with a derivatising agent which provides about the same response to the amino acids included in the sample, in connection with detecting, b) that the pretreatment further comprises heating of the sample, if containing histidine, so as to eliminate double-derivatised histidine, c) that use is made, as the internal standard, of a compound not naturally occurring in the sample and having the structural formula HOOC-R-NH2, wherein R is a straight or branched aliphatic, aromatic or alicyclic chain of carbons with 6-12 carbon atoms, and d) that use is made, in the HPLC separation, of an eluant consisting of acetonitrile in a concentration of 40-65 % by volume and 35-60 % by volume of a buffer at pH 5.5-8.0. |
