Nakajima M, Yamato S, Wakabayashi H, Shimada K
Department of Analytical Chemistry, Niigata College of Pharmacy, Japan.
Biol Pharm Bull. 1995 Dec;18(12):1762-4. doi: 10.1248/bpb.18.1762.
The precolumn derivatization reagent, 2-[2-(isocyanate)ethyl]-3-methyl- 1,4-naphthoquinone (IMQ) was applied to the simultaneous determination of cholesterol and cholestanol in human serum by HPLC with electrochemical detection. The compounds extracted with hexane from human serum, to which was added 1-eicosanol as an internal standard, were reacted with IMQ in acetone and converted into the corresponding carbamic acid esters. After chromatographic separation of the derivatives, they were reduced once in a platinum catalyst reduction column connected on-line, then quantified with an electrochemical detector in the oxidation mode. The detection limits at a signal-to-noise ratio of 3 were 6.6 pg (17 fmol) and 7.4 pg (19 fmol) for cholesterol and cholestanol, respectively in a 10 microliter injection volume. This method was successfully applied to the determination of free and total cholesterol and total cholestanol in normal human serum, and the concentrations of free and total cholesterol were compared with those obtained by an enzymatic method.
柱前衍生试剂2-[2-(异氰酸酯基)乙基]-3-甲基-1,4-萘醌(IMQ)被应用于通过高效液相色谱-电化学检测法同时测定人血清中的胆固醇和胆甾烷醇。从人血清中用己烷萃取的化合物（向其中加入了1-二十烷醇作为内标）在丙酮中与IMQ反应，转化为相应的氨基甲酸酯。衍生物经色谱分离后，在线连接的铂催化剂还原柱中进行一次还原，然后用氧化模式的电化学检测器进行定量。进样体积为10微升时，胆固醇和胆甾烷醇在信噪比为3时的检测限分别为6.6皮克(17飞摩尔)和7.4皮克(19飞摩尔)。该方法成功应用于正常人血清中游离胆固醇、总胆固醇和总胆甾烷醇的测定，并将游离胆固醇和总胆固醇的浓度与酶法测定结果进行了比较。
