| 摘要 |
<p>A method for determining, with an accuracy better than 0.007 %, expressed as Standard Error of Prediction, the concentration of urea in a concentration range of 0-0.1 % in a milk sample containing at least 1 % fat, at least 1 % dissolved lactose, and at least 1 % protein, by an infrared absorption measuring technique, comprising: (a) determining absorption in an infrared radiation waveband from 1000 cm-1 (10.0 um) to 4000 cm-1 (2.50 um) of the milk sample, wherein at least one determination is made in a waveband from 1000 cm-1 (10.0 um) to 1800 cm-1 (5.56 um), in which urea absorbs, at least one determination being made in a waveband in which fat absorbs, at least one determination being made in a waveband where lactose absorbs, and at least one determination being made in a waveband where protein absorbs; (b) determining, on the basis of the absorption determinations and predetermined parameters established by multivariate calibration, a contribution from fat, lactose, and protein in the waveband where urea absorbs, and (c) quantitatively assessing the concentration of urea in the sample on the basis of the absorption in the waveband where urea absorbs and on the basis of the determined contribution from fat, lactose, and protein in the waveband.</p> |
