**3. Electrochemical determination of arsenic (As) using cyclic voltammetry**

Arsenic is the 20th most abundant and high mobile element found in earth crust and exists as dust in air and dissolves in rain water and other water sources easily. The World health organization standard for As concentration must be 10 μg/L, but some parts of the World it exceeds the standard concentration. The excessive intake

#### **Figure 6.**

*Preparation of the electrode [28].*

#### **Figure 7.**

*Cyclic voltammogramms GCE and the fabricated Aus/Py/C-MWCNTs/GCE electrode in 0.1 M aqueous H2SO4 with 1 μM As(III) and without As (III) [28].*

*A Review on Cyclic Voltammetric Investigation of Toxic Heavy Metals DOI: http://dx.doi.org/10.5772/intechopen.108411*

of As causes lung and skin cancer along with negative impacts on cognitive development and increased deaths [27]. Therefore, detection of arsenic in the environment is important for maintaining public health.

Du et al. fabricated a novel Au-stained Au nanoparticles/pyridine/carboxylated multiwalled carbon nanotubes/glassy carbon electrode for the detection of Arsenic (III) traces in real water samples using cyclic voltammetry [28]. The fabrication of the electrode is schematically represnted in **Figure 6**.

Authors observed the peak currents for oxidation of As (0) to As (III) are linear with a concentration of As (III) from 0.01 to 8 μM with a sensitivity of 0.741 mA μM−1 and an LOD of 3.3 nM respectively. Similarly, for the peak currents fort he oxidation of As (III) to As (V) are found to be linear from 0.01 to 8.0 μM with a sensitivity of 0.175 mA μM−1 and an LOD of 16.7 nM respectively. **Figure 7** depicts the cyclic voltammogramms of prepared and gassy carbon electrode (GCE) during the electrochemical behavior of As (III).

Ismail et al. fabricated low cost silica nanoparticles modified SPCE for the detection of As (III) using cyclic voltammetry as shown in the **Figure 8** [29]. They performed optimzation of the experimental conditions and reported that, the anodic peak current exhibited a linear range of 5 to 30 μg/L to the As(III) concentration, with a LOD of 6.2 μg/L. Authors claimed that, the fabricated electrode is very economic with high accuracy, high selectivity, sensitivity, stability with good reproducebility.

#### **Figure 8.**

*Fabrication of silica nanoparticles modified SPCE [29].*


#### **Table 1.**

*Different electrodes used to detect arsenic by cyclic voltammetric method.*

Trachioti et al. fabricated a sparked gold nanoparticles from eutectic Au/Si alloy for the determination of arsenic ın drinking water using cyclic voltammetry [30]. They reported that the anodic peak current was proportional to the arsenic concentration over a linear range of 0.5 to 12 5 ppb, with a LOD of 6.2 ppb. The fabricated electrode exhibited excellent detection capability, high selectivity and reproducibility. Authors claimed that, the fabrication method of electrode is extremely simple and economic with wide scope of applicability. **Table 1** depicts the various electrodes used to detect arsenic by cyclic voltammetric method.
