On-line separation and pre-concentration on a mesoporous silica-grafted graphene oxide adsorbent coupled with solution cathode glow discharge-atomic emission spectrometry for the determination of lead

A method has been developed to improve the sensitivity of the solution-cathode glow discharge-atomic emission spectrometry (SCGD-AES) for lead determination by coupled with flow injection (FI) technique based on an online solid phase extraction (SPE) separation system. A mesoporous silica-grafted graphene oxide (GO-SBA-15) material was used as sorbent and packed it in a SPE microcolumn for its high selective adsorption capacity of Pb(II). An enrichment factor of 15 was achieved under optimized conditions, at a material usage amount of 30 mg, an enrichment flow rate of 1.0 mL min(-1) and an eluent of 0.15 mol L-1 HNO3. The detection limit (DL) of Pb(II) was calculated to be 0.91 mu g L-1. Compared to single SCGD-AES, the sensitivity of Pb(II) was significantly enhanced by FI-SCGD-AES technique and DL could be improved 14-fold. The linear range was 10-2000 mu g L-1 and the relative standard deviation of the method for eleven replicate measurements of 100 mu g L-1 for Pb(II) was 3.8%. The accuracy was validated using certified reference materials of GBW09101b and GBW07310. The method was applied for the determination of target ions in different environmental samples with satisfactory results. (C) 2016 Elsevier B.V. All rights reserved.