On-line Sample Cleanup and Enrichment Chromatographic Technique for the Determination of Ambroxol in Human Serum

A sensitive and efficient on-line clean up and pre-concentration method has been developed using column-switching technique and protein-coated-Bondapak CN silica pre-column for quantification of ambroxol (AM) in human serum. The method is performed by direct injection of serum sample onto a protein-coated-Bondapak CN silica pre-column, where AM is pre-concentrated and retained, while proteins and very polar constituents are washed to waste using a phosphate buffer saline (pH 7.4). The retained analyte on the pre-column is directed onto a C18 analytical column for separation, with a mobile phase consisting of a mixture of methanol and distilled deionized water (containing 1 triethylamine adjusted to pH 3.5 with ortho-phosphoric acid) in the ratio of 50:50 (v/v). Detection is performed at 254 nm. The calibration curve is linear over the concentration range of 12120 ng/mL (r2=0.9995). The recovery, selectivity, linearity, precision, and accuracy of the method are convenient for pharmacokinetic studies or routine assays. © 2012 The Author.