Method development for determining the iohexol in human serum by micellar electrokinetic capillary chromatography

Iohexol is widely used in clinical laboratories as a non-ionic radiographic contrast medium. Determination of its concentration in blood has a vital meaning in preventing its side effects caused by its retention in the system. A method for determining iohexol in serum by micellar electrokinetic capillary chromatography (MECC) requiring no pretreatment is developed. Electrophoresis is performed for serum samples at 25 kV with a borate buffer (50 mM; pH 9.5) containing sodium dodecyl sulfate (50 mM) and detection is carried out at 245 nm. Migration time of iohexol is 7.4 min. Linearity (0–1000 mg/l) is good and detection limit is 0.5 mg/l ( S/ N=3). CV of intra-assay precision at a measurement concentration range of 6.2–200.1 mg/l is 1.38–4.68% and recovery rate is 96–102%. CV of inter-assay precision is 2.06–5.94% at a measurement concentration range of 10.3–155.4 mg/l. This method is characterized by determination through direct injection of serum samples of super micro-quantity into the capillary, which simplifies the determination procedure in a significant manner and improves the precision and accuracy of determination.