靛酚蓝显色法直接测定血浆氨

建立了血浆氨的靛酚蓝直接显色测定新方法，研究了介质酸度、显色时间、共存物质及抗凝剂等的影响。结果表明，以柠檬酸钠作抗凝剂，在pH 10.5～11.2的磷酸盐缓冲体系中显色强度高，干扰小。有色化合物最大吸收波长位于630 nm，表观摩尔吸光系数为2.48×104 L·mol-1·cm-1。血浆氨浓度在0～1 500 μmol·L-1范围线性关系良好(r=0.999 9)，检测下限为1.7 μmol·L-1，相对标准偏差RSD为1.13%(n=11)，回收率为93.6%～101.6%，平均回收率97.0％。用本法测定43例正常人和97例各型肝病患者血浆氨含量均获得满意结果。

Direct Determination of Ammonia in Plasma with Indophenol Method

A new method for direct determination of ammonia in plasmas with indophenol reagent is described. It is shown that using sodium citrate as anticoagulant in phosphate buffer within pH 10.5-11.2, indophenol reagent reacts sensitively with ammonia in the plasmas to form a stable blue compound with a maximum absorption at 630 nm with low interference. The apparent molor absorptivity is 2.48 x 10(4) L x mol(-1) cm(-1) , and the linear range 0-1500 micromol x L(-1) (r = 0.9999) with a detection limit of 1.7 micromol x L(-1). The relative standard deviation is 1.13% (n=11) and the recoveries are in the range of 93.6%-101.6% with an average recovery of 97. 0%. The proposed method has been applied to detect ammonia in the plasmas from 43 healthy persons and 97 patients who suffered from liver diseases with satisfactory results.