CHROMATOGRAPHY, Vol. 26 (2005), No. 2, pp. 59-62
Technical Review
Mixed-mode Column with Size Exclusion and Reversed Phase for Direct LC-MS Analysis of Drug Samples Containing Albumin
Kuniaki Shimbo*, Yoshiji Okada and Hideyuki Kondo
Separation & Refining Materials Group, Showa Denko K.K., 5-1 Ogimachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0867
Abstract:
We developed a simple and rapid method for the direct LC-MS analysis of polar.drugs containing polymer matrix (e.g. proteins) using a
mixed-mode column serving both as a pretreatment and an analytical column. The mixed-mode column with size exclusion and reversed
phase (Shodex MSpak GV-50 2 B) provided successful separation of bovine serum albumin and three kinds of barbitals, which avoided ion-suppression to keep the sufficient sensitivity of each drug in the ESI-negative mode. Isocratic elution with (10 mM ammonium acetate)/acetonitrile
= 70/30 at 0.20 ml/min for 5 min was a simple and rapid procedure compared with the column-switching technique using two columns
and a gradient-elution system.
Keywords:
direct LC-MS analysis, mixed-mode column, size exclusion, reversed phase, isocratic, protein, ion-suppression
