Guentert T W, Coates P E, Upton R A, Combs D L, Riegelman S
J Chromatogr. 1979 Jan 1;162(1):59-70. doi: 10.1016/s0378-4347(00)82063-0.
A specific and precise assay, capable of quantitating in human plasma simultaneously but separately quinidine, dihydroquinidine and the quinidine metabolites 2'-quinidinone, 3-OH-quinidine and a third metabolite found--tentatively identified as the product formed by rearrangement of quinidine-N-oxide-is reported. The assay uses a normal phase high-performance liquid chromatographic (HPLC) system with a variable-wavelength UV detector at 235 nm and has a limit of sensitivity at approximately 20 ng/ml. The mobile phase consists of hexanes-ethanol-ethanolamine (91.5:8.47:0.03). A 2-ml plasma sample is worked up by adding primaquine base as an internal standard and extracting with ether-dichlormethane-isopropanol (6:4:1). The organic extract is evaporated and the residue reconstituted in 100-600 micron1 of mobile phase and an aliquot injected onto the column. Comparison of this procedure with the Edgar and Sokolow (dichloroethane) extraction--fluorescence procedure and with the Cramer and Isaksson (benzene) double extraction--fluorescence assay indicates that both fluorescence procedures give quinidine concentrations up to 2.3 times those determined by HPLC. These discrepancies were shown to be due to carry-over of metabolites and some extraneous background fluorescence.
报道了一种特异性强且精确的分析方法，该方法能够同时但分别定量测定人血浆中的奎尼丁、二氢奎尼丁以及奎尼丁代谢产物2'-奎尼丁酮、3-羟基奎尼丁和第三种代谢产物（初步鉴定为由奎尼丁-N-氧化物重排形成的产物）。该分析方法采用正相高效液相色谱（HPLC）系统，配备可变波长紫外检测器，检测波长为235nm，灵敏度极限约为20ng/ml。流动相由己烷-乙醇-乙醇胺（91.5:8.47:0.03）组成。取2ml血浆样品，加入伯氨喹碱作为内标进行处理，然后用乙醚-二氯甲烷-异丙醇（6:4:1）萃取。将有机萃取液蒸发，残渣用100 - 600μl流动相复溶，取一份注入色谱柱。将该方法与埃德加和索科洛（二氯乙烷）萃取-荧光法以及克莱默和伊萨克松（苯）双萃取-荧光分析法进行比较，结果表明两种荧光法测得的奎尼丁浓度比HPLC法测定值高2.3倍。这些差异表明是由于代谢产物的残留以及一些额外的背景荧光所致。
