On-Line Preconcentration and Simultaneous Determination of Cu and Mn in Water Samples Using a Minicolumn Packed with Sisal Fiber by MIP OES

Abstract

An on-line preconcentration system for the simultaneous determination of Copper (Cu) and manganese (Mn) in water samples was developed and coupled to a microwave-induced plasma optical emission spectrometer (MIP OES). The flow injection system was designed with a minicolumn packed with sisal fiber (Agave sisalana). A multivariate experimental design was performed to evaluate the influence of pH, preconcentration time, and eluent concentration. Optimal conditions for sample preparation were pH 5.5, preconcentration time was 90 s, and HCl 0.5 mol L−1 was the eluent. The main figures of merit were detection limits 3.7 and 9.0 µg L−1 for Cu and Mn, respectively. Precision was expressed as a relative standard deviation better than 10%. Accuracy was evaluated via spiked recovery assays with recoveries between 75–125%. The enrichment factor was 30 for both analytes. These results were adequate for water samples analysis for monitoring purposes. The preconcentration system was coupled and synchronized with the MIP OES nebulizer to allow simultaneous determination of Cu and Mn as a novel sample introduction strategy. The sampling rate was 20 samples/h. Sisal fiber resulted an economical biosorbent for trace element preconcentration without extra derivatization steps and with an awfully time of use without replacement complying with the principles of green analytical methods.

Is MIP-OES a suitable alternative to ICP-OES for trace element analysis?

“…This system provided an enrichment factor (EF) of 30 for both analytes, with recoveries between 75% and 125%, and LODs of 3.7 and 9.0 mg L À1 for Cu and Mn, respectively. 87 In another study, Pita de Sá et al utilized a mini-column packed with p-aminobenzoic acid (PABA-MCM-41) as a separation/preconcentration system for As, Cd, Cr, Cu, Hg, Pb and Zn determination in meat and sh samples. 86 An experimental design to optimize factors directly affecting the SPE procedure (pH, buffer concentration, sample ow, and elution ow) was performed.…”

“…Few articles describing the application of SPE combined with MIP-OES have been published. Silva and Pistón 87 developed an on-line preconcentration system for Cu and Mn, which was coupled to MIP-OES to fast-sequentially determine these analytes in real-time in water samples. The preconcentration apparatus consisted of a mini-column packed with sisal fiber as biosorbent.…”

“…This system provided an enrichment factor (EF) of 30 for both analytes, with recoveries between 75% and 125%, and LODs of 3.7 and 9.0 μg L −1 for Cu and Mn, respectively. 87…”