Hollow Fiber Liquid Based Microextraction of Nalidixic Acid in Urine Samples Using Aliquat 336 as a Carrier Combined...

A new and simple hollow fiber liquid-phase microextraction was used in conjunction with HPLC for the extraction and quantitative determination of nalidixic acid (NA) in human urine samples. This study considers this technique an alternative to common methods of hollow fiber microextraction based on pH gradient and electromembrane extraction of NA in human urine samples. In this research, the drug was extracted from the source phase (donor phase) into a modified organic phase with Aliquat 336 (hydrophobic ion-pair reagent) as a carrier able to impregnate pores of the hollow fiber. In this study, the effects of several factors were tested on the extraction efficiency of the drug. Under optimum conditions, the linearity of the method was observed over the range 0.05-2.0 µg mL(-1) with a correlation coefficient of r = 0.9983. The results of tests on the method determined a good sensitivity with a limit of detection of 0.008 µg mL(-1). The intra-day relative standard deviation (n = 9) for 0.8 µg mL(-1) was 6.2%, and the inter-day relative standard deviation (n = 5) for 0.8 µg mL(-1) was 5.6%. This new strategy was successfully applied to analyze a real urine sample with satisfactory results.