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 on-line 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 μg 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 μg L− 1 and the relative standard deviation of the method for eleven replicate measurements of 100 μg 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.