Okuda T, Yamashita K, Motohashi M
Drug Analysis and Pharmacokinetics Research Laboratories, Takeda Chemical Industries, Ltd., Osaka, Japan.
J Chromatogr B Biomed Appl. 1996 Jul 12;682(2):343-8. doi: 10.1016/0378-4347(96)00096-5.
An on-line solid-phase extraction technique based on column switching (heart-cutting) was developed for direct injection analysis of furosemide in human serum. In order to minimize the influence of deterioration in pre-treatment column efficiency, which was caused by protein precipitation with repeated injections of serum, furosemide was completely enriched at the top of the analytical column by ion-pair formation with tetra-n-butylammonium ion during heart-cutting. The robustness of the established on-line solid-phase extraction system was confirmed under routine conditions. As a result, almost comparable chromatograms could be obtained even though 50 repeated injections of a 100-microliter volume of serum were carried out using one pre-treatment column. The linearity of the calibration curves was demonstrated by the correlation coefficient which was greater than 0.99999 (5-1000 ng/ml). The relative errors and C.V. of quality control samples were within 4.00 and 5.88%, respectively (furosemide concentrations: 5, 100 and 1000 ng/ml).
开发了一种基于柱切换（中心切割）的在线固相萃取技术，用于直接进样分析人血清中的呋塞米。为了尽量减少因反复进样血清导致蛋白质沉淀而引起的预处理柱效率下降的影响，在中心切割过程中，呋塞米通过与四丁基铵离子形成离子对，在分析柱顶部完全富集。在常规条件下证实了所建立的在线固相萃取系统的稳健性。结果，即使使用一根预处理柱对100微升血清进行50次重复进样，也能获得几乎相同的色谱图。校准曲线的线性通过相关系数大于0.99999（5-1000纳克/毫升）得到证明。质量控制样品的相对误差和变异系数分别在4.00%和5.88%以内（呋塞米浓度：5、100和1000纳克/毫升）。
