December 8, 2022

This is my presentation for Undergraduate Research Day at the Capitol 2021. I discuss the work I have done with Dr. Luis Arroyo and Colby Ott to develop an electrochemical screening method for detecting acetaminophen with screen-printed carbon electrodes (SPCEs). I will be available to answer questions in the comments live on 05-March-2021 as part of URDC. The PowerPoint may be viewed and downloaded at the following Google Drive link:

Hello. my name is sara with the west virginia university department and i’m here to tell you about my project, the rapid electrochemical sensing of acetaminophen using screen-printed carbon electrodes in forensic the analyte we focused on is a well-known drug called acetaminophen. whatever you call it, it is very well known because it’s such a common active ingredient,

From the brand name drug tylenol to combination medicines at normal doses, it is effective as a pain reliever and to lower fever. however, it can also harm the liver if too much is taken and we need to be able to detect it in a wide variety of contexts. so for example, since it’s in all pharmaceutical products, we need to be able to measure it there in order for quality

Control purposes. and then, similarly, since patients are taking the drug, doctors need to be able to help monitor it in their systems to help check, is it there? how much is there? and is it too much? however, acetaminophen also shows up in some surprising places. the first of these is in the world of seized drugs. when people sell illegal drugs, that process is not at all

Regulated, so they often include cutting agents in order to increase their profit margins. so, analysts that are looking at these suspected powders need to be able to detect compounds including acetaminophen. because so much acetaminophen is produced, taken, and then excreted all the time, it can end up in the environment, and in particular, in waste water and therefore,

The goal of this work was to develop a fast and inexpensive electrochemical method to serve as a effective screening test for acetaminophen an electrochemical technique involves an electrochemical reaction, which is simply a chemical reaction where electrons are transferred. we say that the compound that lost electrons was oxidized, so we can also call these reactions

Redox reactions which means the instrument applied a changing potential electrochemical techniques are ideal for screening methods they tend to be faster and less expensive than traditional analytical techniques. so, where the patient is, or where we found the suspicious powder, finally, we use screen-printed carbon electrodes for this work which makes them portable and

Allows them to work well with small samples. the first step was to check that it does undergo these electrochemical reactions. so we both increased and then decreased the potential in one run we also started with a high concentration of acetaminophen previously, one mechanism that has been proposed for what happens acetaminophen is oxidized to napqi this parallels one of

The processes that happens in the body. there are enzymes in the body, such as cytochrome p 450, and another reason this is important is that napqi is reactive the next step was to determine what the best ph for analysis was. and we saw that, similar phs performed close to each other. square-wave voltammetry tends to be highly sensitive and very fast. we looked at blank

Buffer which had no acetaminophen added, we did run one scan to increase the potential and look for the oxidation peak and then a second scan in the opposite direction to see the reduction peak. this was successful and we did see both the oxidation and reduction peaks, increasing with increasing concentration whenever acetaminophen was present., however, we did note that the

Potential of the reduction peak did shift both the size of the oxidation peak and the size of the reduction peak one to ten- in parts per million- to ten parts per million. next we wanted to test it out with some simulated samples. to do , we took tap water and added acetaminophen to it. however, tap water does not have many dissolved el- electrolytes in it, therefore,

We diluted this into our ph 9.5 tris hcl. which ended up right in the middle of our linear range at five parts per million after dilution the powder recovered was weighed and then dissolved in distilled water. this was passed through a filter to remove some of the insoluble things from the tablet. and then, this was diluted to a appropriate concentration in the buffer.

Three drops of this solution were analyzed for each tablet, and three tablets were analyzed for a total of nine measurements. the overall results were accurate with a low bias of around one percent. however, the results for each tablet were less accurate and there was very high variability between measurements. and we know that the tablets themselves were accurate and

Consistent and so we suspect that a major source of this variability is that the tablets had a coating and so when they were ground up, for our conclusions, we concluded acetaminophen is electroactive, so the detection of it is feasible and our method should be further developed. and we can tie this in with a larger project that we have been working on to detect other

Analytes with electrochemistry and expand the panel however, some parts of the method should be further refined. and in particular, in addition to working on the electrochemical method itself, the process of actually recovering the acetaminophen from the tablet needs to be improved. for the electrochemical method itself, we want to explore cyclic voltammetry or cyclic

Square-wave voltammetry for the calibration curves since we did see that potential shift when we broke it into the two scans. we also want to look at other supporting electrolytes we’d like to further explore the mechanism for ourselves. and we’d like to see if we can detect it in other matrices besides the tap water. since those are the type of samples that we would get

From a patient. we’d like to do more replicates for the tap water and the tablets and look at more different concentrations for the tap water. and finally, since electrochemistry is a screening method, so it will be important to look at complementary methods so we will look at developing a confirmatory method with lc ms. the funding i received through the honors excel

Program and the university merit scholarship. and i’d like to thank the rest of dr. arroyo’s research group.

Transcribed from video
Rapid Electrochemical Sensing of Acetaminophen Using SPCEs in Forensics, Environmental Applications By Sara K