Solid Phase Extraction of Trace Copper in Aqueous Samples Using C18 Membrane Disks Modified by Benzildithiosemicarbazone Prior to Flame Atomic Absorption Spectrometric (FAAS) Determination

Abstract

A highly convenient, selective and sensitive procedure for pre-concentration, separation anddetermination of sub-ppm levels of Cu2+ in aqueous samples based on modification of octadecyl silica bondedphase membrane (OSBPM) disks is described using benzildithiosemicarbazone (BDSC) as a powerful modifier. Itwas revealed that each loaded OSBPM disk with 6.0 mg of BDSC serves as excellent bead for trapping,enrichment and isolation of trace copper. The analyte was trapped during introduction the aqueous solutionsthrough the surface of each modified membrane, quantitatively, while other interfering ions passed through thedisk to drain. The adsorbed Cu2+ ions were then stripped by appropriate eluting agents followed by monitoring ofthe eluates by FAAS. The effects of sample pH, amount of the modifier, stripping agent types and sample flowrateswere also investigated. The described method permitted a pre-concentration factor of about 200. Thedetection limit of the procedure was predicted to be about 0.013 ng L-1. The method was successfully employed forrecovery and quantification of trace copper in different water samples.