Preconcentration of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) in Clinical Samples by Various Hollow Fiber–Liquid Phase Microextraction (HF-LPME) Configurations With High-Performance Liquid Chromatography (HPLC) Detection

Hollow fiber liquid-phase microextraction is commonly used in analytical chemistry, providing high clean-up and pre-concentration factors. However, a major issue with this method is the long extraction time. The objective of this project is to reduce the extraction time by inducing different types of fluid motion in the sample solution. Three methods were employed: agitation using a magnetic stir bar in the horizontal position (conventional method), utilization of an air pump, and agitation using a magnetic stir bar in the vertical position for the pre-concentration and determination of non-steroidal anti-inflammatory drugs (naproxen, ibuprofen, and mefenamic acid) in biological samples via high-performance liquid chromatography with ultraviolet absorbance detection. The results demonstrated a significant reduction in extraction time and limit of detection when the air pump was employed compared to the conventional method of stirring with a magnetic stir bar in the horizontal position. Moreover, the mentioned parameters were even lower when stirring solutions were accomplished using a vertically-positioned magnetic stir bar, surpassing the method utilizing the air pump for agitation. Furthermore, the relative standard deviations were also lower when a vertically-positioned magnetic stir bar was used compared to the conventional method with a horizontally-positioned magnetic stir bar, while those of the air pump-assisted agitation method fell between the values of the aforementioned methods.