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The majority of chemical experiments conducted during educational programs are carried out in laboratories because they require instructors with special skills, in addition to large, expensive instruments. Recently, there has been an increasing demand for chemical experiments that can be carried out anywhere. Herein, we propose a novel type of paper-based analytical device (PAD) for enabling quantitative analysis without the requirement for a micropipette, since the PAD features a large sample loading zone and a waste zone, enabling accurate volume control of a liquid sample. We initially employed a micropipette to evaluate the PAD and demonstrate the quantitative analysis of ascorbic acid (AA) and pH using different loading volumes. Finally, we determined the AA concentrations and pH values of commercially available beverages using disposable plastic droppers, and the obtained results were in good agreement with those obtained through conventional methods. This PAD format can therefore be used as a novel educational tool for conducting certain chemical analyses in remote learning environments.

We describe a paper-based microfluidic device for iron(III) assay in an applied instrumental analysis laboratory. Simple and convenient devices were fabricated by the students using patterning of f...

Reported herein is a multidisciplinary experiment for senior-level undergraduate teaching laboratories in the synthesis of the analytes acetaminophen and phenacetin; the fabrication of paper-based devices, using eyeliner, acrylic spray paint, or wax-printing, for sensing of those analytes; and the use of the newly fabricated devices for successful qualitative and quantitative analyte detection. This experiment includes elements of organic, analytical, and materials chemistry, as well as device engineering, and provides a strong pedagogical experience for the undergraduate student participants. The experiment was tested over two years in the Advanced Organic Laboratory, and 90% of students over the two years successfully completed all experimental objectives. The modular nature of the reported experiments and inexpensive costs of materials and instrumentation significantly enhance the practical applicability of this experiment and the likelihood of widespread adaptation.

Herein we present a modified iodine clock experiment which replaces starch with cellulose paper. This provides the reaction with a white solid surface in which color change can be clearly observed and reduces reagent amounts required to 540 μL per group. After data acquisition, students are required to calculate reaction orders and the reaction constant k, culminating in their ability to discern the rate equation for this reaction. This experiment is ideal for teaching kinetics in high school and undergraduate settings, particularly if liquid waste disposal is not readily available or if high importance is placed upon minimizing their environmental impact.

Taking a test online rather than on paper is becoming increasingly common. However, there has been little research directly addressing the testing mode (taking a test on paper or online) in chemistry courses, particularly when students take multiple practice tests before an exam. Two studies were conducted to investigate student performance on two proctored general chemistry practice tests as a function of the testing mode. Data were collected in 2013 (Study 1) and again in 2015 (Study 2). The participants were 422 undergraduate students (Study 1 N = 207 and Study 2 N = 215) from a first-semester general chemistry course at a midwestern university. In each study students took two practice tests. Each test included 17 algorithmic, 5 conceptual, and 2 definition questions and was administered on computer or paper. The mode combination of Test 1–Test 2 identified the four conditions: Computer–Computer, Computer–Paper, Paper–Computer, and Paper–Paper. The results show minor differences between online and pape...

A simple and inexpensive paper chromatography experiment that separates and identifies major organic acids in wine and fruit juices has been developed for introductory organic undergraduate student...

In this article, a low-cost, simple, and rapid fabrication of paper-based analytical devices (PADs) using a wax screen-printing method is reported here. The acid–base reaction is implemented in the simple PADs to demonstrate to students the chemistry concept of a limiting reagent. When a fixed concentration of base reacts with a gradually increasing concentration of acid, a dramatic demonstration allows students to discover the limiting reagent by naked eyes observing the color change from phenolphthalein as an indicator. This demonstration is not only a new approach to enhancing students’ learning of the chemistry concept of the limiting reagent, but also presents potential applications of PADs into all levels of chemistry from middle school through college classes.

The Making Introductory Courses Real while Online (MICRO) laboratory project was developed to meet the need for hands-on experiments, focused on topics in analytical chemistry, to be delivered safely remotely or in a socially distanced in-person lab. Unlike more traditional lab experiments, MICRO laboratories use only microgram or nanogram amounts of chemicals; paper microfluidic technology is used to store and mix reactants. Instructional materials use an inquiry-based approach and are situated in a context that highlights the human impacts of the scientific analysis. To support broader-scale implementation of the experiments and promote a shift to more inquiry-based laboratory instruction, an array of supports were developed, including adaptable instructional materials, instructional videos for lab preparation, resource guides, and an introductory workshop. A cohort of nine institutions implemented MICRO laboratories both remotely and in person during Fall 2020. Students were able to successfully complete the experiments, and the inquiry nature of the laboratories led to an increased comfort with the trial-and-error nature of authentic scientific practice. Additionally, most faculty participants indicated a commitment to an increased degree of inquiry in their laboratory pedagogy.

The Journal of Chemical Education announces a call for papers for an upcoming special issue on New Visions for Teaching Chemistry Laboratory.

Tetrakis(4-sulfonatophenyl)porphyrin (TSPP) was immobilized on patterned paper and used as a sensor for heavy metal ions in an advanced organic chemistry course. The resulting sensor could detect Hg2+ and Cd2+ ions colorimetrically, while Cu2+ ion resulted in fluorescence quenching, thus demonstrating a multiplex capability of this paper-based sensor. From the synthesis of the porphyrin to the fabrication of the sensor, advanced undergraduate chemistry students gained first-hand experience with a classical organic synthesis, and also witnessed its application within 2–3 full-day laboratory sessions. This experiment is a good demonstration of how an easily synthesized compound can be exploited to tackle an important problem in real-world situations.

Undergraduate students often find it difficult to understand the chemical principles underlying liquid–liquid extractions. Explanations on how extractions work at the molecular level in textbook and internet resources are plentiful, but students still do not seem able to grasp how extractions work before having to perform the technique in a laboratory course. To address student discomfort with conducting extractions, we developed an Extraction on Paper activity. We envision this activity as a tool to help students understand and apply the chemical principles underlying liquid–liquid extractions outside of and before entering into a laboratory setting.

This work reports the first use of rubber latex waste as the hydrophobic reagent for a low-cost, simple, and rapid fabrication of a paper towel-based experimental device (PTED) with a circular design of 5 mm to demonstrate the factors affecting chemical equilibrium; this serves as a user-friendly means for a laboratory experiment. The illustration of the factors affecting chemical equilibrium is implemented in the PTED. In this approach, the color change of a cobalt(II) complex reaction from pink to blue was observed by the naked eye on the PTED when a tiny drop of hydrochloric acid solution and the treatment of heat by using a hot air dryer (1200 W, 2 min) were applied to the PTED with the precoated cobalt solution (pink color), separately or together. The return of the color of the reactions from blue to pink was carried out by using a tiny drop of water and the treatment of cooling by using an ice bath for 10 min. In addition, the chemical equilibrium constant (Kc) can be easily quantified by processing digital images of the detection zones of PTED captured with a smartphone camera under a control light box at room temperature (≈25 °C), while image analysis was performed using ImageJ software. This PTED laboratory is a new approach not only to enhance students’ learning of the factors affecting chemical equilibrium based on Le Châtelier’s principle, but also to present potential applications of PTED into all levels of chemistry from middle school through college classes.

Paper-based microfluidic devices (μPAD) are a burgeoning platform of microfluidic analysis technology. The method described herein is for use in undergraduate and high school chemistry laboratories. A simple and convenient μPAD was fabricated by easy patterning of filter paper using a permanent marker pen. The usefulness of the device was demonstrated by determination of nitrite ion concentration employing a colorimetric assay. The results for real sample detection using this μPAD were satisfactory and show promise for use in other applications.

The stated purpose of this article is to provide teachers an inexpensive model for laboratory activity and demonstration of galvanic cells using a paper-based device. Metal strips, metal solutions, and KNO3 solution serve as electrodes, metal ions, and electrolyte, respectively. A paper-based device is not only a support for reactions, but also a salt bridge for electrolyte. This activity ought to be interesting to all levels of chemistry from middle school classes through potential applications in upper division college classes. Furthermore, teachers may design and fabricate a paper-based device for their classes in chemistry and also related fields.

Shrinking paper money is a captivating and memorable demonstration of chemistry in action that can be carried out using minimal equipment and reagents. Paper bills can be shrunk down to ∼25% of their initial surface area by treating them with an aqueous solution of sodium periodate. The cellulose in the paper bill is oxidized to dialdehyde cellulose via the Malaprade reaction, and the resulting change in size of the paper money provides macroscopic evidence of the reaction. The chemical change that occurs in the cellulose can be confirmed by a Tollen’s test.

For many years, a type of goldenrod-colored paper has been used as an indicator to demonstrate acid–base behavior, turning yellowish in acidic conditions and reddish in basic conditions. This pH sensitive color change has been the basis of demonstrations involving making hidden messages and pictures using techniques such as printing (e.g., to make a “bloody” red handprint), spraying, wax resist, and electrolytic processes. Candidate dye compounds for the goldenrod paper that feature a pH sensitive yellow/red color change include Direct Yellow 4 and curcumin. Direct Yellow 4, curcumin, and the color-changing goldenrod paper also all exhibit additional changes to darker colors in very acidic solutions (pH < 0). This paper provides evidence that Direct Yellow 4 (or a closely related compound) and not curcumin is the dye present in the color-changing goldenrod paper. These color changes of the Direct Yellow 4 in the goldenrod paper, in conjunction with the fact that paper sheets can display two-dimensional im...

We have developed a simple and direct method to fabricate paper-based microfluidic devices that can be used for a wide range of colorimetric assay applications. With these devices, assays can be performed within minutes to allow for quantitative colorimetric analysis by use of a widely accessible iPhone camera and an RGB color reader application (app) to measure color intensity. In the described laboratory experiment, students design and create their own microfluidic devices with common laboratory supplies such as Kimwipes, Parafilm, and a thermal laminator, and gain hands-on experience in the analysis of Fe2+ and Cu2+ by colorimetric determination.

This technology report outlines the design and construction of a simple Arduino-based pH sensor using universal pH paper; it can be assembled for less than $40 and is ideal for use in laboratory cl...

Paper to Plastics (P2P) is an interdisciplinary program that combines chemistry and biology in a research setting. The goal of this project is 2-fold: to engage students in scientific research and to educate them about sustainability and biodegradable materials. The scientific aim of the project is to recycle unwanted office paper to the useful biodegradable polymer poly(lactic acid) (PLA). Through this program, students learn firsthand how chemistry and biology interact to form useful materials from waste. Students combine biological techniques, such as enzymatic digestion and fermentation, with chemical techniques, such as distillation and catalysis, to accomplish the conversion of waste paper into PLA. Through this summer program, students ultimately become familiar with diverse laboratory techniques, while learning how their scientific interests can be used to address important social problems.

Emerging paper-based diagnostics is an inexpensive yet elegant approach to medical diagnostics and environmental testing in resource-poor regions of the world. Wicking by capillary action distributes a small drop of sample to reagent or assay zones without the need for pumps, refrigeration, or electricity. The advantages of using paper for medical diagnostics (low expense, availability, portability, easy disposal) also apply to the classroom. This article describes a two-session high school activity that employs a paper device to solve a crime scene mystery. On the first day, students role-play either suspects or a detective and make inferences to predict the guilty party. In the second session, students perform presumptive, paper-based forensic testing of “unknown” liquids retrieved from the suspects’ homes and compare these findings with their predictions. The primary goals of this exercise are to demonstrate the similarities between forensic investigation and scientific inquiry and to introduce student...

This article contrasts the normal method for drawing Lewis structures with a two-step systematic approach. The latter approach uses a known molecular connectivity and a knowledge of the number of valence electrons that each atom possesses to visualize bonds that are formed by pairing electrons, one from each atom. This process is repeated until at least one of the non-hydrogen atoms in each bond has an octet. Donor bonds are added when atoms with six and eight electrons are adjacent. In forming donor bonds charges are added to the atoms involved to maintain electron accounting and there is no need to use a formula to calculate formal charges. The general importance of adhering to the octet rule for p-block compounds is stressed and the difference between covalent and donor bonds and the use of the recent IUPAC definition of oxidation state which is based on Lewis structures is included in the discussion. When students are able to draw Lewis structures they can be given access to PC software, available on an academic free basis, which will draw rotatable Lewis structures in 3D for p-block compounds. The software allows the user to move electron pairs in a bow and arrow fashion within the structures and atoms are highlighted when the octet is exceeded.

The Journal of Chemical Education announces a call for papers for an upcoming special collection of Communications on Insights Gained While Teaching Chemistry in the Time of COVID-19.

Turning a linear sugar into its cyclized form is an essential skill in biochemistry. A simple paper model is described that can be used by any student to transform a carbohydrate in its Fischer projection and correctly cyclize it into its Haworth form. The model can also be used to illustrate several key aspects of the Fischer projection of which many students are typically unaware.

The Journal of Chemical Education announces a call for papers for an upcoming special issue on Chemical Safety Education: Methods, Culture, and Green Chemistry.

The Journal of Chemical Education announces a call for papers for an upcoming special issue on Chemical Security.

A glucose-driven enzymatic filter-paper fuel cell is described. A strip of filter paper coated with carbon nanotubes and the glucose oxidase enzyme functions as the anode of the enzyme fuel cell. Another strip of filter paper coated with carbon nanotubes and the laccase enzyme functions as the cathode. Between the anode and the cathode, a third strip of filter paper is placed that holds the glucose, which is the fuel, and that allows the transport of ions. The design of the cell is simple, and all the materials used for the construction are readily available and biocompatible. The cell utilizes the oxidation of glucose to generate electricity and is useful to demonstrate how chemical energy can be converted to electrical energy.

A term-paper assignment that encompasses the full scientific method has been developed and implemented in an undergraduate science writing and communication course with no laboratory component. Students are required to develop their own hypotheses, design experiments to test their hypotheses, and collect empirical data as independent scientists in their personal laboratories—their kitchens. Motivating students to use food preparation as a chemical experiment does more than just provide them with adequate data for their term papers. Students develop a new awareness for experimental variables, acquire experimental planning and development expertise, and gain an enhanced set of independent thinking skills. This inquiry-based assignment requires students to treat edible ingredients as a chemicals and kitchen equipment as scientific instrumentation. Students are required to provide correctly formatted scientific terms for all consumables and equipment, and they are encouraged to bring experimental results into...

An experiment was developed to demonstrate a microfluidic device in the analytical chemistry (instrumental analysis) laboratory. Students made the paper-based microfluidic device with a wax pen and a piece of filter paper and used it to determine the total quantity of amino acids in a green tea leaf extract. The device is low cost, easy-to-make, and easy-to-use. The student results compared favorably with those from standard method.

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.

The Journal of Chemical Education announces a call for papers for an upcoming special issue on Reimagining Chemistry Education: Systems Thinking, and Green and Sustainable Chemistry.

A two to three period analytical chemistry experiment has been developed which allows second year students to explore chemical color tests used to detect adulterated pharmaceuticals. Students prepare several paper analytical devices (PADs) to generate positive and negative controls antibiotics, along with cutting agents such as starch and chalk. These PADs are used to identify the active ingredients and excipients in mystery tablets prepared by their classmates. In the second part of the lab, the students select an individual color test and design an experiment to quantify their mystery pill's active pharmaceutical ingredient (API). Nearly all of the student groups were able to successfully identify adulterants present in their mystery tablets. The quantification of the mystery tablets was also successful with all but one group calculating the correct concentration within 6%. In a postlab assessment, the students identified their largest gains in their ability to analyze data and other information, skill in science writing, and learning of laboratory techniques.

In this laboratory, students perform a synthetic reaction in two ways: (i) by traditional bulk-phase reaction and (ii) in the course of reactive paper spray ionization. Mass spectrometry (MS) is used both as an analytical method and a means of accelerating organic syntheses. The main focus of this laboratory exercise is that the same ionization source can be operated to perform chemical analysis or to accelerate synthesis. More specifically, students explore the effect on reaction progress of operating in one of two modes of paper spray ionization. The modes relate to droplet size that changes as the solvent is depleted from the paper over time. The online mass spectral data for the two modes allow students to see the differences that small changes to spray conditions can have on the MS of a reaction mixture, allowing transition from traditional analysis to accelerated chemical synthesis by simply allowing the paper to partially dry. Chemical analysis and accelerated synthesis can be performed sequentiall...

For the past eight years, we have used online homework software as a pedagogical tool for undergraduate students (almost all are second-year students) learning organic chemistry. Being strong proponents of homework, we were surprised to find that about half of the students who complete 90% or more of the online homework assignments received less than 50% of the available points on examinations, even though comparable problems were given. Students who combined traditional pencil–paper problem solving with the online software performed better than students who solely used the online homework package. Our findings contribute to the ongoing debate between pencil–paper and computer learning with the recommendation that they should be combined to provide students with the ultimate learning tool.

A demonstration is described of electrophoretic separation of carmine and sunset yellow with a paper-based device. The channel in the paper device was fabricated by hand with a wax pen. Electrophoretic separation of carmine and sunset yellow was achieved within a few minutes by applying potential on the channel using a simple and inexpensive power supply. This demonstration could not only motivate the students’ passion in learning analytical chemistry but also introduce two important analytical techniques (microfluidic paper-based analytical devices and electrophoresis) to the classroom. With further modification and improvement, this demonstration may be suitable for students to perform as a laboratory experiment in the teaching lab.

We describe a laboratory experiment that employs the Nanoceria Reducing Antioxidant Capacity (or NanoCerac) Assay to introduce students to portable nanoparticle-based paper sensors for rapid analysis and field detection of polyphenol antioxidants. The experiment gives students a hands-on opportunity to utilize nanoparticle chemistry to develop their own devices to test antioxidant-containing solutions, such as tea and other beverages, for polyphenolic content, a characteristic likely correlated with health benefits. The method utilizes sensing nanoparticles of cerium oxide that respond visually to antioxidant compounds. Due to ease of use of these sensors, inexpensive materials, and short time requirement (∼1 h), this lab is appropriate for primary, secondary, and undergraduate courses. The lab and lesson expose students to the fields of nanotechnology, analytical chemistry, antioxidant chemistry, and antioxidant characteristics of botanicals and food constituents.