Abdel-Latif M S, Guilbault G G
Department of Chemistry, University of New Orleans, Louisiana 70148.
J Biotechnol. 1990 Apr;14(1):53-61. doi: 10.1016/0168-1656(90)90017-6.
Urea was determined using fluorometry with flow injection analysis. O-phthalaldehyde (OPA) reacts with enzymatically generated ammonia and sulfite in alkaline medium to give a highly fluorescent compound that has an excitation wavelength of 372 nm and an emission wavelength of about 430 nm. The method is more selective to ammonia than the one which uses mercaptoethanol in place of the sulfite. Urease was immobilized to a Pall Immunodyne membrane which is commercially available. The immobilization occurs through covalent bonding which results in a highly stable enzyme preparation. The enzymatic membrane was fitted in a 5 cm long, 0.125 inch o.d. Teflon tubing which served as the enzymatic reactor. The system is difficult to use for the analysis of urea in serum because some compounds normally present in serum fluoresce at the same wavelength. This results in higher values for urea. If the reaction system is to be used for the evaluation of urea in serum, a blank should be run so that urea concentration can be calculated by difference.
采用荧光法和流动注射分析法测定尿素。邻苯二甲醛（OPA）在碱性介质中与酶促生成的氨和亚硫酸盐反应，生成一种激发波长为372nm、发射波长约为430nm的高荧光化合物。该方法对氨的选择性比使用巯基乙醇代替亚硫酸盐的方法更高。脲酶固定在市售的帕尔免疫动力膜上。固定化通过共价键合实现，从而得到高度稳定的酶制剂。酶膜安装在一根5厘米长、外径0.125英寸的聚四氟乙烯管中，该管用作酶反应器。该系统难以用于血清中尿素的分析，因为血清中通常存在的一些化合物在相同波长下会发出荧光。这导致尿素值偏高。如果该反应系统用于评估血清中的尿素，则应进行空白试验，以便通过差值计算尿素浓度。
