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Simultaneous Determination of Caffeine and Theophylline in Human Plasma with a Weak Cation Monolithic SPE‐column
Author(s) -
Zhu Tao,
Row Kyung Ho
Publication year - 2010
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.201090250
Subject(s) - chemistry , theophylline , chromatography , caffeine , high performance liquid chromatography , analyte , extraction (chemistry) , solid phase extraction , methanol , detection limit , human plasma , monolithic hplc column , analytical chemistry (journal) , medicine , organic chemistry , endocrinology
A simple reversed‐phase high performance liquid chromatography (RP‐HPLC) method was developed to determine the level of caffeine and theophylline in human plasma samples. The sample clean‐up step involved the on‐line solid‐phase extraction (SPE) of the analytes from plasma samples into a weak cation monolithic column using a column switching system. Separation was performed on a C 18 column (5 µm, 150 mm×4.6 mm) with ultraviolet detection at 274 nm. The mobile phase consisted of methanol‐water (32/68, V/V ) under isocratic conditions at a flow rate of 0.6 mL·min −1 . The measured concentration of caffeine and theophylline showed a good linear relationship over the concentrations range, 0.1–80.0 µg·mL −1 . The absolute recoveries ranged from 77.10% to 85.39%, and the inter‐day and intra‐day relative standard deviations (RSD) were all less than 5%. This method avoids a tedious pretreatment and provides an economic, repeatable and effective method for assaying trace drugs in biological samples.