Solid-phase extraction and large-volume sample stacking with an electroosmotic flow pump in capillary electrophoresis for determination of methotrexate and its metabolites in human plasma.
This paper describes approaches for large-volume sample stacking (LVSS) with an EOF pumpin CE for the determination of methotrexate (MTX) and its metabolites in human plasma. After pretreatment of plasma through a SPE cartridge, a large sample volume was loaded by hydrodynamic injection (3 psi, 70 s) into the capillary filled with phosphate buffer (70 mM, pH 6.0) containing 0.01% polyethylene oxide. Following removal of a large plug of sample matrix from the capillary using polarity switching (-25 kV), the separation of anionic analytes was subsequently performed without changing polarity again, achieving an improvement of sensitivity of around a 100-fold. The method was applied to therapeutic drug monitoring of MTX in one acute lymphoblastic leukemia patient. This study is one of very few applications showing the feasibility of LVSS in analysis of biological samples by CE.
Kuo
Chien-Yuan
CY
Graduate Institute of Pharmaceutical Sciences, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.
Chiou
Shyh-Shin
SS
Wu
Shou-Mei
SM
D000964:Antimetabolites, Antineoplastic / Q000097:blood* / Q000378:metabolism; D002021:Buffers; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D007260:Infusion Pumps; D008727:Methotrexate / Q000097:blood* / Q000378:metabolism; D008991:Monitoring, Physiologic / Q000379:methods*; D010710:Phosphates / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000097:blood
D000964:Antimetabolites, Antineoplastic; D002021:Buffers; D010710:Phosphates; D011092:Polyethylene Glycols; D008727:Methotrexate