Roadside dust.

\* Roadside soil.

**Table 2.** Results obtained for the determination of PGMs concentrations using a SPC/Bi-AgFE nanosensor in dust and roadside soil samples collected from roads near Stellenbosch, Western Cape Province.

using the DPAdSV method. For high accuracy and sensitivity, only single PGM analysis was determined in all experiments using the constructed electrochemical sensor. These results indicate that the constructed SPC/Bi-AgFE nanosensor is more sensitive toward the determination of Pd(II), Pt(II) and Rh(III) in dust and soil samples.

#### **3.7. Comparison of calculated results for different sensor platforms**

To calculate the limit of detection (LOD), the formula 3*σ*/slope was employed, where *σ* is the standard deviation of the blank. The LODs of Pd(II), Pt(II), and Rh(III) obtained under the optimized conditions of these method were 0.7 ng L−1 for Pd(II), 0.06 ng L−1 for Pt(II), and 0.2 ng L−1 for Rh(III) for the SPC/Bi-AgFE nanosensor. In this study, the developed SPCE/ Bi-AgFE nanosensor showed lower limit of detection than previously reported sensors based on the detection of PGMs in environmental samples. To illustrates the repeatability of the sensor, the relative standard deviation (RSD) was calculated and found to be 7.58% for Pd(II), 6.31% for Pt(II), and 5.37% for Rh(III) (*n* = 10). The reproducibility was evaluated using three different electrodes and a solution containing 1.0 ng L−1 of each metal ion with a RSD of 6.81% for Pd(II), 5.11% for Pt(II), and 5.97% for Rh(III).

The analytical performance of the SPC/Bi-AgFE nanosensor was compared with those obtained by other electrochemical sensors described in the literature for the determination of PGMs and illustrated in **Table 3** [35, 36, 44]. From the studies of modified electrodes, this SPC/ Bi-AgFE nanosensor revealed lower limits of detection compared to the reported electrodes for PGMs determination. This developed procedure also reveals high sensitivity and faster response time for PGMs analysis in the presence of DMG, using acetate buffer (pH = 4.7) solution as the supporting electrolyte.

Voltammetric Analysis of Platinum Group Metals Using a Bismuth-Silver Bimetallic Nanoparticles Sensor http://dx.doi.org/10.5772/68132 133


**Table 3.** Comparison of results obtained in present work with other modified stripping voltammetric procedures for the determination of PGMs in model standard solutions and environmental samples are listed.
