Sayyed Hossein Hashemi - Department of Marine Chemistry, Faculty of Marine Science, Chabahar Maritime University, Chabahar, Iran
Prof. Massoud Kaykhaii - School of Natural Sciences (Chemistry), College of Sciences and Engineering, University of Tasmania, Private Bag ۷۵, Hobart, TAS ۷۰۰۱, Australia
Ahmad Jamali Keikha - Department of Mechanical Engineering, Faculty of Marine Engineering, Chabahar Maritime University, Chabahar, Iran
Leila Raisi - Department of Marine Chemistry, Faculty of Marine Science, Chabahar Maritime University, Chabahar, Iran

This research investigates the usage of pipette tip micro solid phase extraction for the separation of ۶-mercaptopurine of complicated matrices before its spectrophotometric detection. To overcome the non-selectivity of spectrophotometry, an ethylene glycol dimethacrylate-based molecularly imprinted polymer was prepared and applied as an adsorbent, which enabled selective and fast extraction of the analyte. To improve the transfer of the analyte to the adsorbent, salting-out effect was employed by the addition of ۳۰۰ mg of NaCl to the sample before performing microextraction. Variables affecting the microextraction of the protocol were investigated utilizing two ways of one-factor-at-a-time and response surface methodology, which showed good consistency with each other. Extraction parameters were optimized as pH of sample = ۹.۰, sample volume = ۱۰ mL, amount of adsorbent = ۲.۰ mg, eluent = ۲۵۰ µL of methanol:acetonitrile (۱:۵ v/v), and extraction and elution cycles of ۱۰ and ۱۲ times, respectively. The dynamic linear range of the protocol was ۱.۰–۱۰۰۰.۰ µg L-۱, with a limit of detection of ۰.۲۵ µg L-۱. The method was compared with extraction by a non-imprinted polymer. The extraction efficiency of the analyte obtained from ۹۶.۰% to ۹۹.۸%, by relative standard deviations better than ۵.۳%. The suggested technique was employed to determine ۶-mercaptopurine in seawater and body fluid samples, and the results were validated by comparing them to a standard HPLC method. The whole analysis time, including microextraction, was about ۲۵ minutes and to perform this method, the sole instrument required is a conventional spectrophotometer.

۶-mercaptopurine, Pipette-tip micro solid-phase extraction, Molecularly imprinted polymer, Response Surface Methodology