Rapaka R S, Roth J, Viswanathan C, Goehl T J, Prasad V K, Cabana B E
J Chromatogr. 1982 Feb 12;227(2):463-9. doi: 10.1016/s0378-4347(00)80399-0.
Modifications of existing rapid high-performance liquid chromatographic procedures for the determination of furosemide in plasma were made in order to achieve greater sensitivity. To a small volume of plasma was added in internal standard structurally related to furosemide. Then, following previously described procedures, acetonitrile was added to precipitate the proteins and the clear supernatant was separated. However prior to injection of the supernatant the pH and composition of the sample were adjusted. This modification of the sample enabled an injection volume of up to 300 microliters of the supernatant to be injected onto the chromatographic column. The effluent was monitored spectrofluorimetrically. A standard linear calibration curve with a mean precision of +/- 4.4% was obtained for plasma samples containing 20--900 ng/ml of furosemide. Two structurally related compounds were used as internal standards in the furosemide assay.
为了提高灵敏度，对现有的用于测定血浆中呋塞米的快速高效液相色谱方法进行了改进。向少量血浆中加入了与呋塞米结构相关的内标物。然后，按照先前描述的步骤，加入乙腈使蛋白质沉淀，分离出清澈的上清液。然而，在上清液进样之前，对样品的pH值和组成进行了调整。对样品的这种改进使得能够将高达300微升的上清液进样到色谱柱上。流出物通过荧光光谱法进行监测。对于含有20 - 900 ng/ml呋塞米的血浆样品，获得了平均精密度为±4.4%的标准线性校准曲线。在呋塞米测定中使用了两种结构相关的化合物作为内标物。
