**4. Conclusion**

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 determi-

**Table 2.** Results obtained for the determination of PGMs concentrations using a SPC/Bi-AgFE nanosensor in dust and

**Carbonate bound Organic bound Fe-Mn bound**

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%

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) solu-

nation of Pd(II), Pt(II) and Rh(III) in dust and soil samples.

**DPAdSV**

BOT, Bottelary Road; OP, Old Paarl Road.

132 Recent Progress in Organometallic Chemistry

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\*

Roadside dust.

Roadside soil.

BOT1\* 4.87 ± 0.22 5.98 ± 0.26 1.84 ± 0.12 BOT2\* 3.68 ± 0.23 3.02 ± 0.29 1.18 ± 0.28 BOT3\* 3.55 ± 0.42 15.93 ± 0.76 2.35 ± 0.26 BOT4\* 4.55 ± 0.24 7.10 ± 0.45 1.23 ± 0.04 OP1\* 2.82 ± 0.08 1.12 ± 0.07 2.17 ± 0.03 OP2\* 3.87 ± 0.20 1.49 ± 0.15 2.57 ± 0.13 OP3\* 3.22 ± 0.37 1.40 ± 0.14 5.09 ± 0.55 OP4\* 4.53 ± 0.14 4.09 ± 0.54 1.08 ± 0.44

for Pd(II), 5.11% for Pt(II), and 5.97% for Rh(III).

tion as the supporting electrolyte.

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

roadside soil samples collected from roads near Stellenbosch, Western Cape Province.

In conclusion, the construction, optimization, and practical application of the SPC/Bi-AgFE nanosensor, which were prepared by drop-coating onto a screen-printed carbon electrode, have been presented. The important DPAdSV parameters were optimized, and well-defined peaks were obtained for Pd(II), Pt(II) and Rh(III) in model standard solutions. To illustrate the practical application of the developed SPC/Bi-AgFE nanosensor, the sensor was tested for the detection of PGMs in road dust and roadside soil samples, collected from the Bottelary and Old Paarl Roads near Stellenbosch in the Western Cape Province. The results obtained for the developed nanosensor provide an alternative sensor platform to replace toxic mercury electrodes and can be used for routine determination of PGMs in road dust and roadside soil with high sensitivity.
