Journal of Chemical Education最新文献

Plant-derived natural products are an important source of potential medicines and continue to have a major impact on the drug discovery process. Natural product discovery assignments provide an opportunity to present various experimental techniques to undergraduate students in introductory medicinal chemistry. This assignment was developed to serve as a meaningful hands-on exercise to introduce undergraduate Chemistry students to the common procedure in the early phase of drug discovery using inexpensive corn silk, in which the final year undergraduate student used Recycling Preparative High-Performance Liquid Chromatography to separate and purify steroids from corn silk. The student used advanced spectroscopic methods such as UV, IR, and one- and two-dimensional NMR to elucidate the structures of these steroids. The cytotoxic activity of these steroids was also evaluated and found to be non-cytotoxic to normal human MRC-5 cells at 60 μg/mL via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. With this assignment, students gain meaningful multidisciplinary hands-on exercises with the common procedure in the early stages of drug discovery and understand the process of isolating natural compounds that may lead to the development of new drugs.

In education, space exists for a tool that valorizes generic student course evaluation formats by organizing and recapitulating students’ views on the pedagogical practices to which they are exposed. Often, student opinions about a course are gathered using a general comment section that does not solicit feedback concerning specific course components. Herein, we show a novel approach to summarizing and organizing students’ opinions as a function of the language used in their course evaluations, specifically focusing on developing software that outputs actionable, specific feedback about course components in large-enrollment STEM contexts. Our approach augments existing course review formats, which rely heavily on unstructured text data, with a tool built from Python, LaTeX, and Google’s Natural Language API. The result is quantitative, summative sentiment analysis reports that have general and component-specific sections, aiming to address some of the challenges faced by educators when teaching large physical science courses.

Millions of people do not have access to clean drinking water; thus, cost-efficient water treatment systems are vital. Chemists, environmentalists, technicians, and engineers will be the professionals making breakthroughs in this industry. This laboratory experiment aims to introduce undergraduate students to the removal of pollutants from water using biochar. Specifically, the study explores the kinetics and thermodynamics of methylene blue adsorption onto biochar using UV–vis absorption spectroscopy. These general chemistry concepts can readily be observed in real time, as the blue color of the methylene blue solution decreases as it adsorbs on biochar. Students in a pilot course have shown their ability to relate thermodynamics and kinetics to the reaction mechanism in the form of a postlaboratory report.

In pharmaceutical laboratory teaching and learning, students’ written reports allow them to document their understanding. Therefore, feedback on these reports is crucial for the students’ continued learning. This study investigates written feedback on laboratory reports and compares the students’ perceptions with teachers’ intentions. The study is based on interviews and student reports containing written feedback notes. Four teachers and five students were interviewed. Results show that written comments are typically brief and intend to quickly guide the students toward further action. However, students often fail to use the comments as intended. Reports are assessed as passed or not passed. Results indicate that students may disregard feedback when their report is passed, showing how a summative element in the feedback may overshadow the intended formative feedback. Teachers and students value oral dialogue in the laboratory. Based on the theory of congruence of learning environments, implications for feedback practices are discussed.

Conducting polymers are critically important materials in organic electronic platforms relevant to sustainability (organic photovoltaics and organic light-emitting diodes) and wearable electronics (organic electrochemical transistors). However, most chemistry students do not receive formal training in the fundamental properties and extensive characterization of these fascinating materials. Described here are four scaffolded learning modules adapted from the primary literature and designed to build the fundamental understanding and practical skills necessary for productive contribution to emerging research in the field of conducting polymers and conducting polymer modified electrodes (CPMEs). These activities were performed by first-year chemistry graduate students and have been used in the lab to orient and equip new student researchers with the electrochemical, spectroscopic, and spectroelectrochemical skillsets central to working in CPMEs. First year master’s students and undergraduate student researchers worked individually to complete data collection, analysis, and interpretation over three 4 h periods with additional time for sample preparation and imaging. Alternatively, one or more of these modules can be adapted and performed by pairs or groups of three over two 4 h lab periods as part of an undergraduate course such as instrumental analysis, polymers, and macromolecules, or as a capstone experience; instructions for these and other modifications are as described herein. If lab equipment and/or available time are limiting factors, sufficient sample data are provided for use as dry laboratories. Through completion of these modules, student researchers learn how to build chemically rational explanations for the electrochemical and spectroscopic signals, to collectively examine data from multiple complementary characterization techniques, and to extract enabling structure–property relationships, all while coming to see themselves as researchers and members of a worldwide scientific community.

The time-resolved detection of very low intensity light emission has become an essential capability in many areas of science including molecular biology, fluorimetry, DNA sequencing, virus detection, nanoparticle research, and optical materials development. Among the most basic techniques for the detection of rapidly fluctuating low-intensity light is photon counting. Despite its extensive applications in the physical and biological sciences and engineering, photon counting techniques have traditionally been left out of undergraduate curricula due to the prohibitive cost of the equipment and the complexity of its operation. However, the recent development of the low-cost silicon photomultiplier device, a solid-state single photon avalanche diode detector, has enabled the availability of easy-to-operate, low voltage, advanced timing performance, and highly sensitive photon counting systems well within the budget of undergraduate teaching laboratories. In this contribution, we provide a strategy to introduce undergraduate interdisciplinary chemistry and physics students to silicon-photomultiplier-based photon counting through the interesting phenomenon of delayed fluorescence from photosystem II in plants. This experiment is perhaps best suited for an upper-level undergraduate laboratory and should stimulate the interest of students across a wide variety of disciplines, from physical chemistry to molecular biophysics to photonics instrumental analysis.

Heterocyclic compounds are an integral part of research, particularly in the pharmaceutical field. The synthesis of such compounds in an undergraduate laboratory can help students understand the relevance and importance of their field of study. Our experimental activity introduces a novel procedure to synthesize coumarin, a heterocyclic formed by two fused rings, using commercial reagents and equipment found in most undergraduate teaching laboratories. What sets our proposed procedure apart is its short reaction time (15 min), high yields (80–85%), and avoidance of extreme experimental conditions, making it highly suitable for implementation in heterocyclic chemistry laboratories at the undergraduate level. The reaction mechanism is straightforward and easily comprehensible to students. Additionally, the fluorescence properties of coumarin are utilized to visually inspect the reaction’s progress and the corresponding purification procedure, enhancing the experiment’s pedagogical value and piquing the student’s curiosity. We successfully implemented this experimental proposal in three different groups, involving approximately 90 students, and received enthusiastic feedback. The heterocyclic compound obtained in the laboratory was highly engaging for the students, as it allowed them to apply the theoretical knowledge gained in their classes to practical experiments. They had the opportunity to explore the reactivities of the functional groups and witness the formation of a compound of great biological importance. The synthesis of heterocycles with notable biological applications serves as an exciting activity for the students. The fluorescent properties of the formed coumarin not only identify the product by visual inspection but also allow them to delve into the concept of fluorescence.

A variety of methods have been used to analyze the kinetics of various processes related to the Diet Coke and Mentos experiment (also known as the soda geyser). However, none of these previous reports has undertaken a quantitative exploration of the dynamics of the creation and collapse of the soda geyser itself. We have therefore devised a method for monitoring the time dynamics of the height of the fountain generated when Mentos candies are added to Diet Coke. The procedure involves collecting a video of the fountain using a smartphone and subsequently analyzing the video using a smartphone application. It is noteworthy that the protocol can be used to investigate a process that lasts only 3–4 s with a time resolution of tens of milliseconds.

Enzyme-like catalysis is the use of artificial catalysts to catalyze chemical reactions, which has the characteristics of enzymatic catalysis, such as high selectivity, high efficiency, and mild reaction conditions. In recent years, 2D materials, thickness ranging from a single to several atomic layers, have become a hot research topic in the field of materials, while 2D materials happen to have enzyme-like catalysis property. Among them, 2H-MoS₂ is easy to peel away to form the 2D structure due to covalent bonds between S–Mo–S in each layer and van der Waals forces between layers. Meanwhile, using a mechanical solid-phase chemical method to produce its S defect, the S defect can significantly improve the catalytic efficiency and achieve rapid catalytic oxidation of TMB (3,3,5,5-tetramethylbenzidine) for quantitative detection of trace ascorbic acid. The experiment described in this study is designed for senior undergraduates majoring in chemistry, materials, chemical engineering, catalysis, etc., as part of their training in comprehensive chemical experimentation. This experiment can introduce students to the synthesis of 2D materials, enzyme-like catalytic reactions, and the principles for the use of analytical instruments. Integrating this experiment into undergraduate teaching will (1) stimulate students to think about developing innovative detection methods answering to actual scientific and social needs; (2) familiarize the students with serious and rigorous scientific method through the process of exploring and optimizing detection methods; and (3) increase students’ understanding of catalytic analysis and detection through exploration of innovative detection methods, thereby raising their practical skills to a high-level.

Physical chemistry may be a quintessential example of a multidisciplinary subfield for the study of chemistry. Although the extent to which mathematics and physics play a role in the theoretical and quantitative expression of chemistry has varied over the 100 years of the Journal, the symbiosis has always been present and the resulting collaborations, fruitful. This editorial introduces a virtual issue that tracks the development and current state of the teaching and learning of physical chemistry as expressed in a curated set of articles from the Journal, celebrating 100 years of publishing educational innovation in chemistry education. The virtual issue can be found here: https://pubs.acs.org/page/jceda8/vi/JCE100yr-pchem.