摘要：It is necessary for the diagnosis of uremia to determine the blood urea (U), uric acid (UA), creatinine (Cr) and methylguanidine (MG), which are uremic toxins, and for judging dialysance to determine vitamine B12 (B12). The simultaneous determination of these substances by high performance liquid chromatography (HPLC) was not reported because it was difficult to separate these substances one another and to separate these substances, especially U, from admixtures in the serum. Proposed method to separate these substances by paired-ion reverse phase HPLC was as follows ; (1) to determine U and UA in serum column ; Zorbax ODS, mobile phase ; phosphate buffer (con-taining 5 mM sodium phosphate, pH 2), to which 2.5 mM sodium hexane sulfate was added as counter ion (2) to determine UA, Cr and MG column and mobile phase were the same as described in (1) except that 80 mM sodium perchlorate was added to the mobile phase (3) to determine Cr, MG and B12 column ; Nippon bunko ODS SS-10A, mobile phase ; perchlorate buffer (containing 15 mM sodium perchlorate, pH 5), to which 20% (v/v) acetonitrile was added. Column temperature was ambient and injection volume was 10μl in the method of (1), (2) and (3). Detection wave length and detection limit of these substances were U : 210 nm, 500 ng, UA : 234, 280 nm, 0.5 ng, Cr : 234 nm, 10 ng, MG : 210 nm, 100 ng and B12 210 nm, 10 ng, respectively. Serum urea determination by reverse phase HPLC without any disturbance of admixtures in the serum was achieved successfully for the first time by use of this method.
