Defense Date


Document Type


Degree Name

Master of Science



First Advisor

Dr. Fred M. Hawkridge


Concern over environmental contamination leading to the introduction of pentachlorophenol into human and animal systems has resulted in the need for a rapid and direct method for determining trace concentrations of this highly toxic compound. A direct electrochemical procedure has been developed for determining trace conccentrations of this phenol dovm to 0.27 ppm. This method uses the electrochemical techniques of differential pulse polarography at the dropping mercury electrode, and differential pulse voltammetry at the carbon paste electrode to reduce pentachlorophenol for this determination. Cyclic voltammetry at the hanging mercury drop electrode has been used to characterize the reaction behavior of pentachlorophenol. Two voltammetric peaks were found with this procedure. A voltammetric peak at -0.4 volts versus Ag/AgCl exhibited the adsorption-desorption characteristics of a non-faradaic reaction by its shape and behavior at different scan rates. A reduction peak at -o.8 volts coupled with its oxidation peak exhibited the behavior for a faradaic electron-transfer reaction, and this peak was used in developing the method for pentachlorophenol. Controlled potential coulometry was used to electrolyze a bulk concentration of pentachlorophenol ix at -1.l volts versus Ag/AgCl in an attempt to obtain enough reduced material to identify the reduction products. This electrolyzed material was investigated with gas chromatography, infrared and UV spectrophotometry, and paper and thin-layer chromatography for this purpose. No reduction products of pentachlorophenol were found with any of these techniques. The surface of the mercury pool, which was used as the working electrode in the coulometric cell, may have been passivated during electrolysis, which prevented significant reduction of pentachlorophenol. The electrochemical procedure that was developed for pentachlorophenol analysis from my research offers some advantages of being fast and direct compared to the methods that are currently available for this purpose.


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