Use of Multiple Square Wave Voltammetry for the Detection of Diquat Herbicide in Environmental Water, Foods and River Sediments

This paper reports the use of multiple square wave voltammetry (MSWV) in the development of a simple, sensitive, fast and low-cost electroanalytical procedure for the diquat herbicide detection in different samples employing a custom-made gold microelectrode (Au-ME). The experimental and voltammetric parameters were optimized, and the use of eight pulses superimposed in each step in the MSWV yielded the detection limits two orders of magnitude greater than those obtained by SWV or previously published chromatographic procedures. Also, the Au-ME allied to MSWV was used to determine diquat in beetroot, onion, peach, environmental water and river sediments. All samples were spiked, and the obtained recovery percentage values were satisfactory for the analytical procedure, showing that Au-ME and MSWV is a suitable tool for diquat residues detection in complex samples.