A REAL-TIME MONITORING IONIC LIQUID CHEMICAL SENSOR FOR HEAVY METALS AND TOXIC POLLUTANTS

Heavy metal and toxic pollutants in water samples cause severe health risks. Current
methods used are time consuming; costly, and involve toxic organic solvents: Areal-time, ionic
liquid monitoring chemical sensor is needed for instantaneous analysis of samples. Ionic liquids,
ion compounds with low melting point, have become popular subject ofstudy because ofthenproperties
especially non-toxicity, no vapor pressure and electrochemical properties. Recent
studies suggest that ionic liquids can be used as solvents, reaction media or electrolyte,
substituting volatile organic solvents, for heavy metals and toxic pollutant electrochemical
activity. This research focuses on the use of ionic liquid for the development of a chemical
sensor to detect and determine toxic analytes especially lead; Lead was chosen as the metal ion
for this study due to its effects on children. [HMIM][TFSI] was chosen for this study due to its
electrochemical and environmental properties and anodic stripping voltammetry (ASY* was
chosen as analysis method due to its sensitivity range, convenience and cost effectiveness. Due
to its simplicity and convenience, carbon paste method was chosen to incorporate the ionic liquid
into the electrode design. Results show that the ionic liquid modified carbon paste electrodes
measure higher current compared to the simple carbon paste electrodes. It is assumed that the
modified electrodes are more sensitive to change in measured current compared to the simple
ones. However, since [H3vHM][TFSI] is a hydrophobic ionic liquid, it alone is not capable of
interacting with lead ion since metal ions are always hydrated in a solution. Metal ions were not
depositing on the electrode surface and there were no peaks registered in the plot. Through
research, it was known that ligands and other types of co-solvents can be used to aid metal ion
penetration into the hydrophobic ionic liquid phase. Thus, it is hoped that the project can be
expanded by incorporating these ligands into the electrode design in the near future. As a
conclusion, the ionic liquid modified carbon paste electrodes shows promising signs to be used
as chemical sensors for lead detections due their electrochemical and environmental aspects.