Date of Award

2015

Degree Type

Thesis

Degree Name

Bachelor of Science (Applied and Analytical Chemistry) Honours

School

School of Natural Sciences

Faculty

Faculty of Health, Engineering and Science

First Advisor

Dr Magdalena Wajrak

Second Advisor

Associate Professor Mary Boyce

Abstract

This work presents a reliable, cost-effective, rapid and infield voltammetric method for the detection of barium. The optimized method consists of an ultrathin mercury film deposited in-situ on a glassy carbon electrode in 0.02 M potassium chloride without deoxygenation; a deposition potential of -2500 mV, pulse height = 50 mV, step duration = 10 ms and a scan rate of 100 mV/s using differential pulse anodic stripping voltammetry (DP-ASV).

The linear working range for barium was determined to be 5 – 80 μg/L (r2 = 0.997), and limit of detection (LOD) was 1.6 μg/L, for 30 sec deposition time. Percent relative standard deviation for 10 measurements performed at 20 μg/L was 5.8%.

Application of the method allowed for the quantitative determination of barium concentration in a variety of waters, brake pad dust and gunshot residue (GSR) samples. Comparative analysis of sample results from DP-ASV with inductively-coupled plasma mass spectroscopy (ICP-MS) showed a mean percent difference of 1.8%. The method also permitted the simultaneous measurement of barium and lead, crucial for GSR samples.

Available for download on Saturday, March 10, 2018

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