simultaneous synthesis of dual ldh/cobalt oxide sorbents on pencil graphite substrate for using in solid phase microextraction of some environmental pollutants and quantitative measurement via hplc

Todays, toxic compounds such as toluene, benzene and phenolic compounds are known as carcinogens, which the presence of these compounds, even in low concentration, in the groundwater aquifers is dangerous and these types of pollutants are highly toxic and carcinogenic according to the who regulations [1]. in this context, microextraction methods can be used to pre-concentrate the desired compounds [2]. one of the most interested technique, which is used for the extraction of analytes is solid phase microextraction (spme) [3], which is considered as a suitable method for pre-concentration and extraction of experimental species. recently, layered double hydroxide (ldh) and co3o4 have solely been used as sorbents in the extraction phases in the spme method. the mentioned sorbents have shown incredible properties for the extraction of some analytes. the main objective of the present study is to simultaneous synthesis of the both ldh and co3o4 on the same time on the surface of a very cheap pencil graphite substrate. by using this sorbent, hydrogen bonding and the anion exchange as two different forces were lead to extraction of the analytes, which caused the selectivity of the method. herein, the ldh was accommodated on the surface of the pencil graphite electrode by the electrochemical method, and then, some part of the ldh were changed into the co3o4 by thermal method. finally, this fiber, which is containing the two adsorbents was used for the extraction and measurement of some of the desired species, including benzene, toluene and some chlorophenols in drinking water samples. the extracted compounds were finally eluted with an organic solvent and injected into the hplc apparatus for measurement. based on the obtained results, rsds were higher than 5.6 % and for btex compounds were better than 5.8 %.