Hollow fiber-protected liquid-phase microextraction followed by high performance liquid chromatography for simultaneously screening multiple trace level β-blockers in environmental water samples

Abstract

A sensitive and reliable method using a two-phase hollow fiber liquid-phase microextraction (HF-LPME) pretreatment technique was developed for simultaneously screening multiple β-blockers in environmental samples. In this study, heptanol was chosen as the optimal extraction solvent, and six β-blockers with a wide range of polarities were extracted across the porous walls of hollow fibers and into the acceptor phase (AP). The fundamental parameters affecting the extraction efficiency (EE) of analytes including extraction time, temperature, pH of the donor phase (DP) and AP, stirring speed, volume of the sample solution, ionic strength and the type of hollow fiber membrane were studied and optimized. Under optimal conditions, extracts were analyzed by HPLC with ultraviolet detection (UV). Finally, satisfactory results were obtained, good linearity was observed for all β-blockers in the range of 0.16–200 ng mL⁻¹, limits of detection (LODs) were between 0.08 and 0.5 ng mL⁻¹, the intra- and inter-day precision values of the six β-blockers were 1.0–2.2% and 1.4–2.7%, respectively. The recovery with RSDs was less than 2.2% for the pretreatment method. The proposed technique was successfully applied for screening multiple β-blockers in complex aqueous samples with the best specificity and provided a simple and reliable new means for the self-checking of laboratories at the basic level.