Solid phase microextraction of trace levels of copper in serum samples of hepatitis B patients, on activated carbon cloth modified with an ionic liquid by using a syringe mountable filter technique
Abstract
A simple, inexpensive and miniaturized solid phase microextraction method using a syringe mountable filter as a substitute for batch and column techniques was developed for rapid extraction and determination of copper ions (Cu2+). Activated carbon cloth (ACC), modified with the ionic liquid (IL), 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6], was used as sorbent. The modified ACC was packed on mountable membrane filter in a plastic syringe system. The surface modification, elemental composition and characterization of ACC were confirmed using scanning electron microscopy, energy dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy. The sample solution treated with a complexing reagent, ammonium pyrrolidine dithiocarbamate, was drawn into the syringe filled with IL-ACC and dispensed manually. Then the Cu2+ complex sorbed on the IL-ACC was quantitatively eluted by drawing and dispensing of different concentrations of acids. The influence of different variables on the extraction efficiency, including the concentration of ligand, pH, sample volume, eluent type, concentration and volume, and interfering ions was investigated using flame atomic absorption spectrometry. In order to validate the developed method, a certified reference material (CRM) of human serum (Sero-M10181®) was analyzed, which indicated a non-significant difference in the experimental and certified values. The proposed method was successfully applied for the determination of Cu2+ in serum samples of hepatitis B patients and healthy controls.