DEVELOPMENT OF MULTIWALLED CARBON NANOTUBES BASED SOLID PHASE EXTRACTION FOR THE DETERMINATION OF TRACE LEVEL OF Mn(II) AND Sn(IV) IN RIVER WATER SAMPLES

Abstract

This paper reports a multiwalled carbon nanotubes (MWCNTs) modified with 3-amino-7-dimethylamino-2-methylphenazine (Neutral Red, NR) as a new solid phase extractor for determination of ultra trace amounts of Mn(II) and Sn(IV). The metal ions were retained on -column filled with the solid phase at a flow rate of 3.0 mL/min. The retained metal ions were eluted with 3 mol L⁻¹ solution of HCl and measured by flame atomic absorption spectroscopy (FAAS). The effect of different variables such as, sample pH, concentration of 3-amino-7-dimethylamino-2-methylphenazine (Neutral Red, NR), sample flow rate, eluting solution and the effect of interfering ions have been investigated systematically. The calibration graph was linear in the range of 0.4-100 µg L⁻¹ and 0.6-150 for Mn(II) and Sn(IV), respectively. Under optimized conditions, the limit of detections (LOD) were 0.12 and 0.16 µg L⁻¹ for Mn(II) and Sn(IV), respectively. The method was used for determination of target metal ions in some water samples from rivers located in industrial and nonindustrial areas.