Application of Graphene as a Sorbent for the Preconcentration and Determination of Trace Amounts of Copper in Urine Samples Prior to Flame Atomic Absorption Spectrometry

The potential of graphene as solid-phase extraction adsorbent for the separation and preconcentration of copper (Cu) has been investigated. Cu could be adsorbed quantitatively on graphene in the pH range of 4.0-7.0, and then eluted completely with 2.0 mL of 2.0 mol L/sub -1/ HNO/sub 3/ solution at a flow rate of 2.0 mL/sub -1/. A new method using a microcolumn packed with graphene as the sorbent was developed for the preconcentration of trace amounts of Cu prior to their determination by flame atomic absorption spectrometry (FAAS). Several effective parameters on the extraction and complex formation were selected and optimised. Under optimum conditions, an enrichment factor of 150 was obtained. The calibration graph was linear in the concentration range of 10.0-180.0 microg L/sub -1/ with a detection limit of 0.27 microg L/sub -1/. The relative standard deviation for ten replicate measurements of 10.0 and 70.0 microg L/sub -1/ of Cu were 3.68% and 3.35%, respectively. The method has been applied for the determination of trace amount of Cu in urine samples with satisfactory results. (author)