| 释义 |
Kjeldahl Biochem.|ˈkɛldɑːl|
The name of Johann Kjeldahl (1849–1900), Danish brewing chemist, used attrib. and in the possessive to denote a method of estimation of nitrogen invented by him, in which the organic substance to be analysed is treated with concentrated sulphuric acid and the ammonium sulphate so formed is converted by excess alkali to ammonia, which is then titrated; Kjeldahl flask, a glass flask having a round bottom and a long wide neck, used in the Kjeldahl method.
1885Jrnl. Chem. Soc. XLVIII. 688 (heading) Nitrogen determinations by Kjeldahl's method. 1909P. B. Hawk Pract. Physiol. Chem. (ed. 2) xxii. 382 Place 5 c.c. of urine in a 500 c.c. long-necked Jena glass Kjeldahl flask. 1964[see colorimetrically adv.]. 1970R. W. McGilvery Biochem. xxviii. 704 The Kjeldahl method has the advantage of being applicable to insoluble materials, such as most foodstuffs, and the disadvantage of not distinguishing proteins from other sources of nitrogen, such as nucleic acids, urea, and the like. |