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This lab experiment uses [sup 31]P NMR spectroscopy of biomolecules to determine pKa values and the binding energies of metal/biomolecule complexes. Solutions of adenosine nucleotides are prepared, and a series of 31P NMR spectra are collected as a function of pH and in the absence and presence of magnesium or calcium ions. The chemical shifts in the spectrum change depending on the protonation state of the phosphate groups and the nucleotide/metal interaction. Because 31P NMR spectroscopy is used, the resulting data are clean and readily accessible for student analysis. The use of 31P NMR spectroscopy presents a rich opportunity to deepen student engagement with NMR spectroscopy and spectral analysis. Furthermore, the inclusion of biomolecules and metal binding exposes students to important and underrepresented concepts that bridge organic chemistry and biochemistry. Students will learn how to prepare, collect, and analyze non-hydrogen samples using NMR spectroscopy, identify an unknown pKa, and calculate binding energies for a metal complex. This experiment is suitable for students in a second-year undergraduate organic chemistry course and could also be used in an analytical chemistry, bioorganic chemistry, or an advanced instrumentations laboratory course. [ABSTRACT FROM AUTHOR]

The techniques learned in a laboratory translate into strong critical thinking aptitudes as well as adeptness in complex problem-solving within research. Typically, these laboratory skills are not acquired until a budding scientist enters graduate school since many undergraduate laboratories are more procedural than investigative. Therefore, the module in discussion was designed to aid students in developing competence toward thinking like a scientist. Through utilization of an inquiry-based approach, a laboratory involving high performance liquid chromatography was transformed into a blended online learning experiment. While students were provided in-class time to interact with their peers and the instructor and TA, the majority of the work and development was done outside of class. All background information and protocols were provided outside of the lab via an online course management system including the PowerPoint videos that students used to prepare for the experiment. The students used those materials to ultimately determine the identity and number of different steroids in an unknown sample. The objective was to determine if this approach promoted the metacognitive skills of students and encourage the use of argumentative skills when presenting and justifying claims and data. [ABSTRACT FROM AUTHOR]

Bioinorganic topics are ubiquitous in the inorganic chemistry curriculum; however, experiments to enhance understanding of related topics are scarce. In this proposed laboratory, upper undergraduate students assess the biological interaction of molybdenocene dichloride (Cp2MoCl2) with bovine serum albumin (BSA) by fluorescence spectroscopy. Specifically, learners study the quenching mechanism by performing a binding titration of a bovine serum albumin (BSA) solution with molybdenocene dichloride at physiological pH at three temperatures to determine the biomolecular quenching constant as defined in the Stern-Volmer equation. The temperature dependency of the quenching constant allows estimation of thermodynamic parameters which in turn permits an assessment of the nature of the intermolecular interactions involved. This educational activity promotes graph interpretation and integration of concepts such as metallocene-protein interaction, fluorescence quenching, Gibbs energy, entropy, and enthalpy, where students learn to propose a quenching mechanism and to assess the intermolecular forces that may be involved. The proposed experiment can be implemented in various educational settings such as inorganic chemistry, biochemistry, biophysical chemistry, and analytical chemistry. [ABSTRACT FROM AUTHOR]

Despite the importance of asymmetric catalysis in both the pharmaceutical and commodity chemicals industries, asymmetric catalysis is under-represented in undergraduate chemistry laboratory curricula. A novel guided-inquiry experiment based on the asymmetric aldol addition was developed. Students conduct lab work to compare the effectiveness of different catalysts in catalyzing the asymmetric aldol addition of a ketone and an aldehyde. Working in pairs, students use a variety of analytical techniques including 1-D and 2-D NMR spectroscopy and chiral chromatography and write their final report in the format of an ACS style publication. Although this experiment was designed for an advanced undergraduate synthesis laboratory course, it can be readily adapted for use in an organic or an inorganic laboratory course. [ABSTRACT FROM AUTHOR]

This experiment is dedicated to second-year and above undergraduates who are in their experimental session of the analytical chemistry course. Grouped students are required to use a TiO2 photocatalytic oxidation process to treat the methanol-containing wastewater that resulted from their previous HPLC experiments. Students learn to assemble a specified apparatus for a chemical reaction and analytical methods for the determination of environmental pollutants and reaction intermediates. The comprehensive experiment can give students a deep insight into application of several instruments (COD analyzer, UV-vis, GC-FID, and GC-MS) and the principle of photocatalytic oxidation reaction. Meanwhile, upon the completion of the experiment, students not only become aware of the wastes they generate but also understand how chemistry can be utilized for environmental remediation. [ABSTRACT FROM AUTHOR]

Laboratory courses are often designed using step-by-step protocols which encourage students to conduct experiments without thinking about what they are doing or why they are doing it. Such course design limits the growth of our students as scientists and can make it more difficult for a student to transition to the expectations of a research laboratory experience. To facilitate student growth in the process skills necessary to transition from the teaching laboratory to the research laboratory, an advanced biochemistry laboratory was redesigned to be team-taught and project-based culminating in a 7 week group research project in which the students worked collaboratively to propose, design, and troubleshoot their own experiments. Here, we report perceived student learning gains which provide additional evidence that inquiry- and research-based pedagogies impact student confidence with respect to the process skills required for self-directed research. [ABSTRACT FROM AUTHOR]

High-resolution mass spectrometry (HRMS) features both high resolution and high mass accuracy and is a powerful tool for the analysis and quantitation of compounds, determination of elemental compositions, and identification of unknowns. A hands-on laboratory experiment for upper-level undergraduate and graduate students to investigate HRMS is described. This experiment was developed in response to students' requests and provides a hands-on overview of the range of capabilities of an HRMS instrument. Students were encouraged to explore and investigate all the various modes in which the instrument can be operated. This experiment prompted students, even those with little experience in mass spectrometry, to think about how HRMS could be best incorporated into their research projects. [ABSTRACT FROM AUTHOR]

In this paper, we describe an experiment for the undergraduate physical chemistry laboratory in which students determine the speed of sound in the gases He, N2, CO2 , and CF3CH2F. The experimental apparatus consists of a closed acrylic tube containing the gas under study. White audio noise is injected into one end of the tube, and the sound amplitude is recorded as a function of time at the other end. The data are recorded and Fourier transformed in real time with a spectrum analyzer application on an Apple iPad. The resulting frequency spectrum of the cavity standing waves is used to determine the speed of sound in the gas by least-squares fitting, with experimental values that fall within about 0.2% or less of the accepted values. The speed of sound is related to the heat capacity ratio in the ideal gas limit, providing students with quantitative evidence of the nonideality of the gases at ambient pressure and temperature. The experiment demonstrates the power and accuracy of interferometry and Fourier analysis using a modern tablet computer. [ABSTRACT FROM AUTHOR]

An introduction to digital stochastic simulations for modeling a variety of physical and chemical processes is presented. Despite the importance of stochastic simulations in chemistry, the prevalence of turn-key software solutions can impose a layer of abstraction between the user and the underlying approach obscuring the methodology being employed. This article introduces the use of random variable generators in simulating physical and chemical processes suitable for use in undergraduate chemistry courses through detailed illustrative examples which include DNA sequences, Brownian motion, diffusion, chemical kinetics, and chain-growth polymerization. The results of the stochastic simulations are also compared to theoretical models. Jupyter notebooks containing Python code for running these simulations are provided in the Supporting Information section. [ABSTRACT FROM AUTHOR]

Quantum mechanics is a notoriously difficult subject to learn, due to a lack of real-world analogies that might help provide an intuitive grasp of the underlying ideas. Discrete energy levels and absorption and emission wavelengths in atoms are sometimes described as uniquely quantum phenomena, but are actually general to spatially confined waves of any sort. Here, we provide an experiment demonstrating the acoustic spectroscopy of a drum. We show that a struck drum emits sounds of discrete frequencies (tones), and that the lifetime of each emitted tone is directly related by Heisenberg's uncertainty principle to its line width in the drum's frequency spectrum. We also show that a still drum absorbs only those same frequencies when exposed to monochromatic sound from an audio speaker. The resonant motion of the drum membrane is too fast to see by eye (>60 Hz), but can be observed with the aid of a strobe light. The observed resonant modes of the drum are the eigenfunctions of a particle trapped in an infinite circular well, and analogous to the shapes of atomic orbitals (1s, 2p, 3d, 2s, etc.). This experiment can be built for under $50, and is an excellent demo or lab exercise for general and physical chemistry courses to provide a visual example of abstract quantum mechanical ideas. [ABSTRACT FROM AUTHOR]

Complexation TOPOS is a free software package to generate 3-D topographic surfaces ("topos") for metal-ligand complexometric titrations in aqueous media. It constructs surfaces by plotting computed equilibrium parameters above a composition grid with "volume of ligand added" as the x-axis and overall system dilution as the y-axis. The sample systems in this paper are restricted to EDTA as a ligand. Other chelating ligands that form exclusively 1:1 complexes could also be modeled with this software. The surfaces show the quality of the equivalence point break under various conditions. More importantly, they develop the phenomenon of metal ion buffering. They clearly distinguish the difference between "pseudo-buffering" and "true buffering". They introduce terminology for two different forms of metal ion buffering: (1) mass action metal ion buffering under excess ligand conditions and (2) precipitate metal ion buffering when hydroxide precipitates are present under excess metal ion conditions. Systems modeled are EDTA titrations of Cu2+ and Mg2+. Supporting Information for this paper includes the Complexation TOPOS software, an Excel workbook that generates topos in under 20 seconds. Required inputs are the following: (1) a stability constant for the metal-ligand complex, (2) acid dissociation constants for the ligand, (3) stability constants for hydroxy complexes of the metal, and (4) a Ksp value and stoichiometry for hydroxide precipitates. Many constants are tabulated in a workbook tab. Also included are a PowerPoint lecture and teaching materials (for lecture, homework, and prelaboratory activities) that are suitable in general chemistry courses or third-year and graduate courses in analytical chemistry, biochemistry, and geochemistry. [ABSTRACT FROM AUTHOR]

The principles of process oriented guided inquiry learning (POGIL) are applied to a binary solid-liquid mixtures experiment. Over the course of two learning cycles, students predict, measure, and model the phase diagram of a mixture of fatty acids. The enthalpy of fusion of each fatty acid is determined from the results. This guided inquiry experiment, which was developed as part of the POGIL-PCL (Physical Chemistry Laboratory) Project and tested at multiple institutions, relies on "green" materials and can be carried out by students using simple or sophisticated apparatus. [ABSTRACT FROM AUTHOR]

Attracting a general audience to STEM topics can be a challenge, and developing engaging and interactive instruction is important for educators in all fields. While many chemical educators have successfully used pop-culture themes to introduce their students to scientific concepts, these encounters are largely limited to formal classroom environments. Inspired by the successes of community science programs such as Science Café and Nerd Nite, science educators from two Nebraska campuses sought to broaden the exposure of their pop-culture themed class lectures, and created the SciPop Talks! program. Now entering its fifth year, this informal educational outreach program has become a model of faculty/librarian partnerships and successful campus outreach. In this article, we discuss the program's formation, outline its strengths and challenges, and stress the importance of using interactivity to engage with learners. We report on findings from a survey of our attendees, which revealed surprising differences along gender lines. By sharing the motivations, strategies, operational specifics, outcomes, and future goals, we hope that scientists, science educators, outreach coordinators, and librarians will be inspired to launch their own SciPop Talks! programs. [ABSTRACT FROM AUTHOR]

A structured inquiry experiment for inorganic synthesis has been developed to introduce undergraduate students to advanced spectroscopic techniques including paramagnetic nuclear magnetic resonance and electron paramagnetic resonance. Students synthesize multiple complexes with unknown first row transition metals and identify the unknown metals by correlating spectroscopic data to electronic structure. Students are assessed through an oral presentation of their spectral analyses and conclusions. Data are included in Supporting Information for institutions without access to an EPR. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials have promising utility in chemical sensing including applications in preserving occupational safety, monitoring of environmental pollution, and human health. While recent advances in device fabrication and molecular design of functional materials have enabled rapid fabrication of chemical sensors from carbon nanomaterials, limited efforts have focused on translating these discoveries into undergraduate curriculum. This paper describes a safe and engaging laboratory exercise that introduces undergraduates and younger students to modern nanoscience while illustrating fundamental principles of general chemistry that include concepts of orbital hybridization, allotropes, and intermolecular interactions. Solid-state devices are prepared on shrinkable polymer film substrates equipped with hand-drawn graphite electrodes. Chemiresistive sensing materials, carbon nanotubes (CNTs) and graphite powder, are compressed into pellets and drawn directly into this device architecture to produce functional sensors capable of detecting and differentiating gases and vapors based on differences in intermolecular interactions. [ABSTRACT FROM AUTHOR]

Many instrumental analysis students develop limited skills as the course rushes through different instruments to ensure familiarity with as many methodologies as possible. This broad coverage comes at the expense of superficiality of learning and a lack of student confidence and engagement. To mitigate these issues, a peer-led team learning model was developed to give each student in-depth experiences operating and troubleshooting six common instruments. Electronic cigarette solutions were chosen for all work because of their current relevance. Small groups became "class experts" on their assigned instrument. Students were responsible for teaching their peers how to utilize their instrument for experimentation. Each student rotated through their peer's instruments, learned to apply the knowledge they gained from one instrument to others, while they answered questions from peers. The students developed troubleshooting and communication skills--foundational tools for chemists. This model proved successful in promoting cognitive flexibility and critical thinking about experimental design, as reflected by oral quizzes and peer teaching. This adaptation of peer-led team learning helped engage students, promote confidence, and a facilitate a deeper understanding of instrumentation. [ABSTRACT FROM AUTHOR]

An advanced undergraduate experiment involving the synthesis and characterization of a series of six unique cinnamamides is described. This experiment allows for a progressive mastery of skills students need to tackle more complex NMR structure elucidation problems. Characterization of the products involves IR spectroscopy, GCMS, and proton, carbon, and nitrogen NMR analyses. Understanding the principles of advanced NMR techniques, including nitrogen NMR spectroscopy, is highly relevant to advanced organic chemistry students. [ABSTRACT FROM AUTHOR]

Animations and static visualizations can greatly help students think about concepts on the particulate level. A laboratory activity introducing Crystal Field Theory and Ligand Field Theory was developed based on multiple theories of science learning and pedagogies and combined multiple learning cycles with particulate, macroscopic, and symbolic representations. Through a combination of self-paced online modules and in-class inorganic syntheses, the majority of students met the learning goals relating structure to properties for cobalt(III) complexes. [ABSTRACT FROM AUTHOR]

NMR spectroscopy is traditionally introduced to students during Organic Chemistry as a tool used for structure elucidation and conformational analysis. NMR spectroscopy also has numerous applications beyond structure determination, including quantitative analysis of samples. For this study, an experiment was developed to use quantitative analysis functions of a 400 MHz NMR to quantify the ethanol content in different liquor samples during an Instrumental Analysis course. The concentrations of alcohol in vodka and other liquors were determined using the electronic reference to access in vivo concentrations (ERETIC) method embedded in the NMR processing software. ERETIC was used to analyze a proton NMR spectrum to define the concentration of ethanol in the reference sample, generate a calibration curve, and calculate the concentrations of ethanol in commercial samples. [ABSTRACT FROM AUTHOR]

Synthetic polymers are all around us in the 21st century, ranging from commodity items made from poly(ethylene) and poly(vinyl chloride) to high-tech materials for aerospace, electronics, and medicine. Yet polymer chemistry is often neglected in formal chemical education. Once students recognize the many ways in which polymers are part of their everyday lives, they are motivated to learn about how polymers are made, their unique thermal, mechanical, and optical properties, and how plastics, fibers, elastomers, and adhesives all are possible because of long-chain molecules. Recognizing the importance of synthetic polymers as well as biopolymers, supramolecular structures, and nanoscale materials, the American Chemical Society (ACS) Committee on Professional Training now requires teaching of at least two of these topics in chemistry courses for ACS-certified undergraduate degrees. This special issue of the Journal is a contributed collection of papers describing how polymers are being taught in general, foundational, and advanced chemistry courses and also in high schools, workshops, and demonstrations for the public. The papers in general do not describe complete courses; instead, they describe modules and experiments that could be implemented at different educational levels and in different environments. The papers are sources of ideas of how instructors can incorporate polymer chemistry into their own courses. [ABSTRACT FROM AUTHOR]

A laboratory experiment was developed to enable students to investigate the use of smart hydrogels for potential application in targeted drug delivery. This is challenging for students to explore practically because of the extremely high risks of handling cross-linking agents such as glutaraldehyde. Genipin is a safe and green alternative that has been combined with chitosan and poly(vinyl alcohol) to form a pH-sensitive hydrogel. In this problem-based learning mini-project, students can study the swelling behaviors, oscillatory functionality, gelation, fluorescence, optical, and release properties of this system. Students in the third year of an undergraduate chemistry degree program have successfully conducted this laboratory experiment as part of a problem-based learning mini-project. [ABSTRACT FROM AUTHOR]

Inorganic polymers can be introduced in a variety of undergraduate courses to discuss concepts related to polymer chemistry. Inorganic polymers such as silicates and polysiloxanes are simple materials that can be incorporated into an introductory or descriptive inorganic course. Polymers based on inorganic carbon, including diamond and graphite, can likewise be used to introduce concepts related to structure-property relationships. Diamond and graphite can be discussed in more detail in an upper-division inorganic chemistry course as well as an introduction to coordination polymers and semiconducting organic polymers. Herein, these materials are briefly discussed in terms of how they can be merged into relevant coursework. [ABSTRACT FROM AUTHOR]

Behaviors characteristic of and unique to polymers are demonstrated through four simple experiments: (i) comparison of the dilute solution viscosities of a small molecule and a high-molecular-weight polymer, (ii) observation of the properties of a "slime", (iii) the stretching of a rubber band, and (iv) a simple paper-and-pencil simulation experiment for the step-growth polymerization of X-Y (or A-B) types of monomers. The described demos have been performed for audiences ranging from middle school to university graduate students to successfully introduce and explain why polymers and materials made from them behave uniquely. [ABSTRACT FROM AUTHOR]

Polymer nomenclature is important because it is part of the language of polymer science and is needed for polymer identification, reference, and documentation. A primer on polymer nomenclature is provided herein for people new to the field or for instructional use. Both structure-based and source-based nomenclatures, together with trivial and trade names, are described. Source-based nomenclature is commonly used by polymer scientists for polymers where the starting monomers are known. The structure-based approach is especially helpful when the chemical structure of a polymer is well-defined; it is part of the recommendations from the International Union of Pure and Applied Chemistry and Chemical Abstracts Service. Appropriate illustrations of these approaches are provided. [ABSTRACT FROM AUTHOR]

The 2015 Guidelines approved by the Committee on Professional Training of the American Chemical Society require that the curriculum for the certified undergraduate degree include the principles that govern macromolecular, supramolecular, mesoscale, and nanoscale systems. The rationale for this new requirement recognizes that the synthesis, analysis, and physical properties of small molecules give an incomplete picture of the higher-order interactions that occur in these systems. Programs can satisfy this requirement through an in-depth course on these systems or distributed coverage over two or more required courses. It is anticipated that the majority of undergraduate degree programs will include at least some coverage of synthetic polymers, but there may be concerns in many departments on how best to implement such coverage. Suggested topics that illustrate important aspects of the chemistry and properties of synthetic polymers in the curriculum are described. [ABSTRACT FROM AUTHOR]

An upper-division undergraduate polymer chemistry course was developed as a blended/hybrid course. The students met face-to-face once a week for 75 min with all other components being available online. Face-to-face meetings were used for class discussions/problem-based lectures, student presentations, hands-on activities, and examinations. Online components included study guides, the Macrogalleria, and online quizzes. This course is appropriate for students who have had one year of organic chemistry. [ABSTRACT FROM AUTHOR]

Siloxane polymers and silicone materials are major components in most people's daily lives and are important in a wide variety of applications. However, despite their undeniable importance, they are often overlooked in the traditional undergraduate education, as they do not fall neatly into the traditional categories of organic or inorganic chemistry. Even in advanced polymer courses, they are often overlooked despite their value in describing many important polymer concepts. Herein we present three simple experiments to introduce siloxane polymers to the undergraduate education aimed at first-year, upper-level, and non-science-major students. This is prefaced with a brief overview of the history and chemistry of siloxanes and their value as teaching tools in the laboratory and classroom settings. [ABSTRACT FROM AUTHOR]

Because fossil fuels are a nonrenewable resource, alternative sources of chemical carbon will be necessary as petroleum based chemicals decline during the 21st century. Carbon dioxide can serve as a source of carbon for the synthesis of useful chemicals, thereby contributing to a sustainable chemical industry. A promising technology for CO2 utilization is the alternating copolymerization of epoxides and CO2 to afford polycarbonates. This article describes the catalysis of this polymerization process employing well-defined transition metal catalysts. It is intended for use in advanced inorganic chemistry courses, which are required for an ACS-approved degree in Chemistry, and integrates concepts in inorganic chemistry and polymer science. Concomitantly, a goal of this material is to contribute to the recently established polymer requirement by the Committee on Professional Training (CPT) for an ACS-certified degree. The principles of inorganic chemistry are shown to play vital roles in the mechanistic aspects of this copolymerization process. [ABSTRACT FROM AUTHOR]

A multi-instrument approach has been applied to the efficient identification of polymers in an upper-division undergraduate instrumental analysis laboratory course. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) is used in conjunction with differential scanning calorimetry (DSC) to identify 18 polymer samples and to determine whether polyethylene samples are high density or low density and whether nylon samples are composed of nylon-6 or nylon-6,6. This experiment introduces students to the use of two different instruments to qualitatively analyze several polymers in an efficient manner. [ABSTRACT FROM AUTHOR]

A laboratory experiment is described that extracts the tetrapyrrolic teal-colored biliverdin IXα, as its dimethyl ester, from commercially available emu eggshells. The extraction of ~10 mg samples of biliverdin is simple and requires two 3 h lab periods: A two-step acid digestion and liquid-liquid extraction, followed by short silica gel flash column chromatography. The deeply colored extract can be characterized by TLC, UV-vis, IR, ¹H NMR spectroscopy, ESI+ mass spectrometry, or its diagnostic chemical reduction to the yellow derivative bilirubin. A small-scale variant of this extraction requires only a single 3 h lab period, and the extracts can be analyzed by UV-vis spectroscopy, ESI+ MS, or HPLC. An introduction to the biological origin of biliverdin is provided. This pedagogically flexible project combines natural product isolation with the spectroscopic characterization of a multifunctional biomedically important compound and touches upon many aspects of chemistry and biology. The colorful experiment is appropriate for the introductory organic chemistry laboratory and possesses the prerequisites for a chemistry-biology interlaboratory approach. [ABSTRACT FROM AUTHOR]

Drones, unmanned aerial vehicles (UAVs), usually helicopters or airplanes, are commonly used for warfare, aerial surveillance, and recreation. In recent years, drones have become more accessible to the public as a platform for photography. In this report, we explore the use of drones as a new technological filming tool to enhance student learning in the field of analytical and environmental chemistry. In particular, chemistry students have difficulty in applying knowledge learned in the practical context, e.g., finding potential sites for soil sampling. Our effort was focused on improving the understanding of terrain and examining potential "good" sampling sites by providing instructor's point of view (IPOV) videos filmed with a drone. Students responded positively to this innovative filming method in a perception survey. The merits and challenges of filming with drones will be discussed. [ABSTRACT FROM AUTHOR]

An improved apparatus for measuring freezing points has been developed. Compared to the traditional Beckmann freezing point instrument, the improved one overcame prior difficulties with solidification of liquid and made the solid-liquid equilibrium reversible with heat compensation from a heating tube. The reliability and accuracy were carefully examined by determining the freezing point of the solvent and solution, as well as calculating the molar mass of the solute. It was found that the molar mass was in good agreement with the literature data. Thus, this improved device can effectively and successfully be used in undergraduate physical chemistry laboratory courses. [ABSTRACT FROM AUTHOR]

Making optimal pedagogical and predictive use of the radius ratio rule to distinguish between solid state structures that feature tetrahedral, octahedral and cubic holes requires several updated insights. A comparative analysis of the Born-Landé equation for lattice energy is developed to show that the rock salt structure is a suitable choice for radius ratios between 0.326 and 1.00. The lower bound is the ratio at which the energy of the rock salt structure matches that of the zinc blende structure, all other things being equal. The upper bound extends all the way to unity because the relative energy of the rock salt and CsCl structures are within 1% of each other for radius ratios above 0.717, which is the ratio at which the energy of the rock salt structure matches that of the CsCl structure. Geometric analysis of 154 1:1 ionic compounds that can potentially adopt the zinc blende, rock salt, or CsCl structure demonstrates that while existing ionic radii can be used for predictions with substantial success, a more applicable set of predictive ionic radii based on cubic lattice parameters can be deduced. [ABSTRACT FROM AUTHOR]

Laboratory experiments were developed to introduce students to the quantitation of drugs of abuse by high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Undergraduate students were introduced to internal standard quantitation and the LC-MS/MS method optimization for cocaine. Cocaine extracted from paper currency was analyzed with a simple and rapid LC-MS/MS method. Students in advanced laboratories determined the amount of amphetamine, methamphetamine, and oxycodone on currency in addition to cocaine. The LC-MS/MS method has a short run time (2.5 min) to allow for a high throughput of student samples. [ABSTRACT FROM AUTHOR]

An open-source electrochemistry simulation package has been developed that simulates the electrode processes of four reaction mechanisms and two typical electroanalysis techniques: cyclic voltammetry and chronoamperometry. Unlike other open-source simulation software, this package balances the features with ease of learning and implementation and can run on mainstream operating systems. In an elctroanalysis lecture for graduate students, we have simulated the cyclic voltammetry of an electron transfer reaction with varied scan rates. The dynamical concentration profiles were demonstrated in an animation to help students understand the relation between currents and evolving concentration profiles, and the relations between peak currents and scan rates were also discussed. [ABSTRACT FROM AUTHOR]

Circular dichroism (CD) has emerged as one of the standard biophysical techniques for the study of guaninequadruplex (G4) folding, cation effect, and ligand binding. The utility of this technique is based on its robustness, ease of use, and requirement of only small quantities of nucleic acid. This experiment is also extendable to the classroom and adaptable to students from graduate school in a multidisciplinary area, bridging chemistry, biochemistry, and medicinal chemistry. Specifically, students employ a solution of a nucleic acid that can adopt a G4 conformation, anneal it in the presence of a metal cation, and assess the folding and topology by the characteristic CD signatures. During the class experiment, it was also possible to interconvert the G4 topology by changing the cation type, and to determine the melting temperature of the G4 structure in the absence and presence of molecules called G4 ligands. The current experiment used the commercially available porphyrin TMPyP4 as a G4 ligand and human telomeric 22AG and mutated oncogene promoter c-MYC G4 structures to illustrate the CD applicability in a context that can be explored or adapted to a student's course level and topic. [ABSTRACT FROM AUTHOR]

This article describes a combined UV-photometer and fluorimeter constructed from 3 LEDs and a few wires, all held in place with Lego bricks. The instrument has a flexible design. In its simplest version, two UV-LEDs (355 nm) are used as light source and to detect absorption, and a third LED, in the visible spectrum (e.g., 525 nm), is used to detect fluorescence. Various experiments are described: fluorescence as a function of concentration and light source intensity; quantitative measurements of quinine in tonic water, using absorption and fluorescence measurements, with results in line with those obtained on scientific instruments; a demonstration of the inner filter effect reducing fluorescence at higher concentrations; investigation of the effect of drinking tonic water on the fluorescence of quinine in urine; temperature effects on fluorescence; chloride-ion quenching of fluorescence with result comparable to those previously reported; and, finally, a demonstration of phosphorescence. [ABSTRACT FROM AUTHOR]

Virtually all modern chemical instrumentation is controlled by computers. While software packages are continually becoming easier to use, allowing for more researchers to utilize more complex instruments, conveying some level of understanding as to how computers and instruments communicate is still an important part of the undergraduate curriculum. Understanding how digital and analog signals are used to allow the smooth operation of an instrument allows the user to better understand the possible sources or problems when instruments stop working optimally. The experiment presented here allows students to investigate the communication between the computer and a high-performance liquid chromatography (HPLC) system by allowing them to construct a LabVIEW-based control program. Student understanding of instrument control is reinforced by having them control pump speed, detector zeroing, and a solvent recycling valve while also monitoring the injection port status and the detector output. Students gain an understanding of the HPLC process by incorporating all of the instrument tasks into their control software and then use their system to analyze a mixture of five small organic molecules, thereby gaining insight into the chemical concepts underlying HPLC separations. [ABSTRACT FROM AUTHOR]

Analyzing and understanding data directly from primary literature can be a daunting task for undergraduates. However, if information is put into context, students will be more successful when developing data analysis skills. A classroom activity is presented using protein denaturation to help undergraduate biochemistry students examine myoglobin structure. Student learning goals are to understand relationships involving molar absorption coefficients and light absorbance, quantum yield and fluorescence, guanidine hydrochloride and protein folding, as well as protein folding and spectral properties of aromatic amino acids. This activity was performed by 56 students over three years. Results show statistically significant gains in student learning and student reported increased understanding. [ABSTRACT FROM AUTHOR]

A laboratory experiment for students in advanced inorganic chemistry is described. In this experiment, students prepare two metal complexes with a potentially bidentate-carbene ligand. The complexes are synthesized by reaction of a bisimidazolium salt with silver(I) oxide or palladium(II) acetate. Silver and palladium complexes are binuclear and mononuclear species, respectively, in which the carbene ligand behaves in a different coordination mode. The reaction conditions are straightforward and the complexes air-stable species, even though the palladium compound must be prepared using air-free techniques. Students must also assign the signals in the ¹H and 13C-{¹H} NMR spectra. The complexes showed a fluxional behavior in solution as can be deduced from their ¹H NMR spectra. The students are given the 3D structures of the complexes as an aid to understand this dynamic behavior. The students should also use the FAB-mass spectrum of the silver complex and the concept of isotopic pattern in order to discriminate between a mononuclear and a binuclear structure. [ABSTRACT FROM AUTHOR]

Advances in 3D printing technology over the past decade have led to its expansion into all subfields of science, including chemistry. This technology provides useful teaching tools that facilitate communication of difficult chemical concepts to students and researchers. Presented here is the use of 3D printing technology to create tangible models of reaction progress surfaces. Easy-to-follow step-by-step instructions are provided for the creation of these surfaces from IR, NMR, and HPLC data. More generally, this procedure enables conversion of any arrayed data set into a 3D-printable STL file. The general utility of these 3D-printed models is highlighted with three unique case studies. [ABSTRACT FROM AUTHOR]

Validation of analytical methods is a fundamental subject for chemical analysts working in chemical industries. These methods are also relevant for pharmaceutical enterprises, biotechnology firms, analytical service laboratories, government departments, and regulatory agencies. Therefore, for undergraduate students enrolled in majors in the field of chemistry, learning validation of methods and chemometrics is essential. The following article presents the development of a laboratory experiment to validate a method to determine CO2 by means of potentiometry. This experiment will allow students to approach a subject that may be part of their professional activities. The validated method was applied to determine CO2 in commercial carbonated beverages. A teaching activity on method validation was proposed and implemented for senior students. After its application, students were able to improve significantly their knowledge on the topic. The potentiometric technique, underlying the validated method, has the advantage of being easy to apply and accessible in almost any undergraduate laboratory. Furthermore, the required reagents are available practically in any chemistry department. The shown procedures might be executed as laboratory activities in analytical chemistry due to their overall simplicity and rapidity. [ABSTRACT FROM AUTHOR]

This paper presents a programming project named NMRviewer that allows students to visualize transformed and processed ¹H NMR data in an accessible, interactive format while allowing instructors to incorporate programming content into the chemistry curricula. Using the MATLAB graphical user interface development environment (GUIDE), students can build an NMR viewer software program via three main features: a display window, an open file dialogue, and a stack plot option. The experience is designed so that students acquire basic notions of flow diagrams, control loops, Boolean logic rules, and further aspects of the syntax of coding in MATLAB. By building and using the NMR viewer, students can improve their skills and understanding of basic concepts of programming, a discipline often undervalued in current undergraduate chemistry curricula. Importantly, the described NMRviewer is designed for Bruker's data and the Windows operating system, although the tools provided in this project allow students to build their own viewers adapted to their needs. [ABSTRACT FROM AUTHOR]

Electronic spectra often exhibit vibronic structure when vibrational and electronic transitions occur in concert. Theory reveals (1) that orbital symmetry considerations determine specific roles played by the nuclear degrees of freedom and (2) that the vibrational excitation is often highly regiospecific, that is, attributable to an identifiable subset of atoms within the molecule. Spectra obtained from a chromium(III) complex involving a macrocyclic ligand and two axially disposed butadiynide groups nicely illustrate many of the concepts involved. [ABSTRACT FROM AUTHOR]