Abstract
Multi-Walled carbon nanotubes are used as preconcentrating probes for the quantitative determination of trace cadmium, copper and lead in environmental and biological sample using graphite Furnace Atomic Absorption Spectrometry and inductively coupled Plasma Optical Emission spectrometry. The method is based on the electrostatic interactions of positively charged Cd+, Cu+ and Pb+ with the negatively charged multi-walled carbon nanotubes (MWCNTs) for the preconcentration and isolation of analytes from sample solutions. Effective preconcentration of trace cadmium, copper and lead was achieved in a pH range of 5 - 7, 5 - 7 and 4 - 7, respectively. The retained cadmium, copper and lead were efficiently eluted with 0.3 mol·L-1 HCl for graphite Furnace Atomic Absorption Spectrometry determination. The multi-walled carbon nanotubes packed micro-column exhibited fairly fast kinetics for the adsorption of cadmium, copper and lead, permitting the use of high sample flow rates up to at least 3 mL·min-1 for the flow injection on micro-column preconcentration without the loss of the retention efficiency. The detection limits (3σ) were 0.03, 0.01 and 0.5 ng·mL-1 for Cd, Cu and Pb, respectively. The relative standard deviation under optimum condition is less than 2.9% (n = 10). The developed method was successfully applied to the determination of trace Cd, Cu and Pb in a variety of environmental and biological samples.
Highlights
Graphite furnace atomic absorption spectrometry (GFAAS) still continues to be one of most attractive approaches for trace element analysis in most laboratories due to its relatively low operational and instrumental costs, easy operation, and low sample throughput
Multi-Walled carbon nanotubes are used as preconcentrating probes for the quantitative determination of trace cadmium, copper and lead in environmental and biological sample using graphite Furnace Atomic Absorption Spectrometry and inductively coupled Plasma Optical Emission spectrometry
The retained cadmium, copper and lead were efficiently eluted with 0.3 mol·L−1 HCl for graphite Furnace Atomic Absorption Spectrometry determination
Summary
Graphite furnace atomic absorption spectrometry (GFAAS) still continues to be one of most attractive approaches for trace element analysis in most laboratories due to its relatively low operational and instrumental costs, easy operation, and low sample throughput. Direct GF-AAS determination of trace amounts of elements is usually difficult owing to its insufficient detection power. For this reason, the preliminary separation and preconcentration of trace elements from matrix is often required [1]. The majority of works published on flow injection (FI) on-line preconcentration for graphite furnace atomic absorption spectrometry (GF-AAS) has been executed with packed columns either by ion exchange or by adsorption [2]. The purpose of the present work is to assess the feasibility of the use of multi-walled carbon nanotubes as an adsorbent for determination of the trace elements Cd, Cu and Pb in environmental and biological samples with GF-AAS
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