Journal of Chromatography & Separation Techniques
Open Access

Abstract

On-Line Solid-Phase Extraction Based on Poly (Nipaam-MAA-co-EDMA) Monolith Coupled with High-Performance Liquid Chromatography for Determination of Nitrendipine and Nisoldipine in Human Urine

Yanhui Duan, Haiyan Liu, Suying Sun, Yanzhao Gu, Jia Li and Gengliang Yang

A solid-phase extraction absorbent material based on poly (N-isopropylacrylamide-co- methacrylic acidco-ethylene glycol dimethacrylate) [poly (NIPAAm-MAA-co-EDMA)] monolithic column was developed for the simultaneous determination of nitrendipine and nisoldipine from human urine. The morphology of monolithic column and pressure drop across the columns were characterized. The results showed excellent permeability and high selectivity. Urine samples (0.05 mL) were injected directly onto the prepared Solid-Phase Extraction (SPE) monolithic column. Most biological matrix compounds in urine were removed by on-line SPE technology, while nitrendipine and nisoldipine retained on the SPE column were effectively separated on a C18 analytical column. For all analytes, linear calibration curves were obtained over a range of 50-500 ng/mL with coefficient of correlation > 0.9996. Accuracy and precision for inter- and intra-day assay showed acceptable results for quantitative assay with Relative Standard Deviation (RSD) less than 10%. The recovery was found to be in the range of 89-102%. The results indicated that the prepared monolith was feasible to be use as an on-line SPE sorbent material and the method was especially appropriate for multi-analytes monitoring in urine samples.