From April 4 to April 7, chemistry majors David Aupperle and Abigail Praklet attended the National Conference for Undergraduate Research (NCUR) at the University of Oklahoma in Oklahoma City. Both students gave oral presentations describing their research with analytical professor Grace Muna. The fact that each of their efforts spanned more than one semester or summer of work is a testament to their dedication and love of chemistry. Aupperle and Praklet had a wonderful time at the conference (travel was supported by a SMART travel grant) and we are proud to have them represent our department and university. The titles of their talks and abstracts are given below.
Electrochemical Detection of Estrogenic Compounds Using Palladium Nanoparticle Modified Electrodes
David Aupperle, Professor Grace Muna
Chemical pollution in water is one of the major environmental problems in today’s world. Polluted water poses a threat to the aquatic organisms and human health. The pollutants such as estrogenic phenolic compounds (EPCs) need to be monitored constantly to control their impact on the environment and the ecosystem. These EPCs can be found in fresh water from waste treatment facility effluents as well as agricultural runoffs. Although the concentrations these compounds are typically low in the ng/L range, they have been found to feminize male fish and disrupt human endocrine function. Electrochemical detection provides an alternative to other analytical methods because it has attractive attributes such as high sensitivity, less expensive instrumentation, ease of sample preparation and field deployable. This work utilized the unique properties of electrodes modified with metal nanoparticles. The nanoparticles circumvent the electrode fouling seen on bare electrodes during the electro-oxidation of phenolic compounds. In the present work, glassy carbon and gold electrodes were modified with palladium nanoparticles to catalyze the electro-oxidation of EPCs. The modified electrodes exhibited good catalytic properties, good response precision and stability. For example, 50 consecutive measurements for 100 mcM estriol solution using palladium modified gold electrode gave a %RSD of 5.3%, indicating good reproducibility and response stability exhibited by the modified electrode. Future directions will be to couple the modified electrode to flow injection analysis and high-performance liquid chromatography. Results from the analytical performance of palladium modified glassy carbon and gold electrodes towards the catalytic oxidation of EPCs will be presented.
Developing a Sensitive Stripping Voltammetric Method to Detect Lead in Water and Soil
Developing a Sensitive Stripping Voltammetric Method to Detect Lead in Water and Soil
Abigail Praklet, Keon Jones, Joseph Williamson, Professor Grace Muna
Lead is one of the most toxic heavy metal in the environment. Its presence is due to human activities notably, lead in gasoline, lead-based paint, lead-containing pesticides, lead in ammunition and sinkers, and incinerator ash or water from lead pipes. Lead poisoning can cause a number of adverse human health effects, but it is particularly detrimental to the neurological development of growing children. Therefore, frequent testing and precise monitoring of Pb in soil and water is important to assess and control lead contamination. We hereby report on developing a stripping voltammetric method using glassy carbon electrodes modified with bismuth nanoparticles (GC-BiNPs) to detect lead in drinking water and soil. Voltammetric stripping measurements have historically utilized mercury in the forms of hanging mercury drop and mercury film electrode to measure heavy metal ions. This is mainly because clean surfaces can be easily be regenerated with a new mercury drop. However, because of mercury toxicity and risks associated with its disposal its use as an electrode material for stripping measurements is severely restricted. We’re utilizing the unique properties of bismuth such as its ability to form alloys with different metals, to develop a sensitive method to detect lead. Preliminary results show that using GC-BiNPs we can detect low levels of lead down to one part per billion in water. The research findings on the stripping voltammetric method development will be presented.
