synthesis and application of a porous carbon material as a new sorbent for solid phase extraction of vitamin b12

Recently, many research studies have been focused on the development of new sorbent materials in solid phase extraction (spe) procedure. among different kinds of sorbents, carbon based materials appear as efficient sorbents because of their good interactions with organic compounds [1]. also, porous materials due to having high surface area and high adsorption capacity are considered as interesting sorbent material. recently, ionic liquids were used as precursor for preparation of carbon material via pyrolysis process [2]. vitamin b12 is an essential nutrient for cell development and human growth. it acts as a coenzyme for normal dna synthesis and plays an integral role in development of the myelin sheath [2]. the deficiency of vitamin b12 in humans is manifested by anemia and neuropathy [3]. it is very important to diagnose vitamin b12 at a sensitive level. methods for determination of vitamin b12 remain limited due to their low sensitivity and poor selectivity. here, a porous carbon material was synthesized by pyrolysis of an ionic liquid composed of citric acid and tetrabutyl ammonium bromide and applied as an efficient sorbent for extraction of vitamin b12 by dispersive solid phase extraction method and determination by hplc/uv. the characteristics of the synthesized carbon material such as size, morphology, chemical composition, thermal stability and porosity with different techniques such as fe-sem, edx, xrd, tga, bet and raman and ft-ir spectroscopy were studied. different variables affecting the extraction efficiency were investigated and optimized. in this method, the target analyte was extracted from 30 ml of the aqueous sample solution at ph 5.0 and 5% nacl during 15 min, and desorption was performed by 300 µl methanol. the optimized methodology exhibited a good linearity between 1.0 and 250 µg l-1 (r2 > 0.998) with the relative standard deviation (rsd%) less than 4.9 (n = 5). the applicability of the method was demonstrated with the analysis of different samples including tap water and milk, and good results were obtained. obtained results demonstrated proposed sorbent has advantages of rapid and efficient extraction of vitamin b12 due to the high porosity and surface area of the proposed sorbent.