In this study, hollow fiber liquid phase microextraction (HF-LPME) coupled with highperformanceliquid chromatography (HPLC) with UV detection was applied for preconcentrationand determination of Diclofenac sodium in biological fluids. Parameters affecting the extractionprocess including pH of donor phase and acceptor phase, type of extraction solvent, stirring rate,extraction time, and salt addition were studied and optimized. Under the optimized conditionsdonor phase pH=3, acceptor phase pH=11.7, extraction solvent n-octanol, stirring rate =750 rpm,extraction time=27 min and without the addition of salt, enrichment factors up to 170 wereachieved and the relative standard deviation (RSD %) of the method was within the range of 2-3%. The method was successfully applied to determine the concentration of diclofenac sodium inthe biological samples and satisfactory results were obtained. Manuscript profile

Atomoxetine, an attention-deficit/hyperactivity disorder (ADHD) agent , has severe adverse effects, which even causes suicidal ideation in patients and when combined with other drugs such as monoamine oxidase inhibitors or in patients with cardiovascular disorders or pheochromocytoma, it can be fatal. In order to monitor the trough level of the drug, sensitive analytical methods are in demand.Therefore, for detection of trace levels of this drug, the trend solvent bar microextraction method coupled with HPLC-UV were implemented. Application of pH gradient of 10.3 and 3.0 (donor and acceptor phase, respectively) enabled preconcentration and microextraction of the target analyte. The results were modeled using Artificial Neural Network (ANN) successfully.The optimum results were obtained with a stirring rate of 365 rpm and salt addition by 15.1% at 25°C after 26 min. The limit of detection and quantification were 7.0 ng mL-1and 20 ng mL-1, respectively. It offered good linearity range of 20-5000 ng mL-1 with a coefficient of estimation higher than 0.9972 and a preconcentration factor of 112. The relative standard deviations of analysis were 4.6% within a day (n=3) and 6.2% between days (n=9).Overall, this method can be employed for several purposes such as for dosage adjustment in ADHD patients, clean validation in the pharmaceutical industry, and for trace determination in forensics. Manuscript profile