An Inexpensive Electrodeposition Device and Its Use in a Quantitative Analysis Laboratory Exercise

This experiment describes the construction of a simple apparatus for effecting the electrodeposition of nickel onto a tared copper electrode. Results are compared to the determination of nickel by the classical gravimetric precipitation of the dimethylglyoxime complex.

The full citation is here: Parker, R. H.  J. Chem. Educ. 2011, 88, 1428–1430 and a link to the article is provided below (subscription to the journal required).

http://dx.doi.org/10.1021/ed101202t

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How Much Cranberry Juice is in Cranberry-Apple Juice?

Students determine the amount of cranberry juice (as a volume percent) in mixtures of cranberry juice and apple juice by measuring the absorption of mixtures and comparing to a calibration curve prepared for cranberry juice. The experiment assumes that the absorbance of apple juice is negligible at the analytical wavelength, which isn’t strictly true. The experiment can be modified easily by a simultaneous analysis at two or more wavelengths.

The full citation is here: Edionwe, E., Villarreal, J. R., Smith, K. C.  J. Chem. Educ. 2011, 88, 1410–1412 and a link to the article is provided below (subscription to the journal required).

http://dx.doi.org/10.1021/ed2002237

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Leeching of Silver from Silver-Impregnated Food Storage Containers

Food storage containers may contain micro-particles of Ag, which serves as an anti-microbial agent to limit the growth of molds, fungi, and other microorganisms. Students study the leeching ability of three solvents — deionized water, tap water, and acetic acid — by measuring the concentration of silver in the leechate using graphite-furnace atomic absorption spectrophotometry. An analysis of variance is used to evaluate the relative importance of container type, solvent, extraction time, and the application of heat during the extraction.

The full citation is here: Hauri, J. F., Niece, B. K.  J. Chem. Educ. 2011, 88, 1407–1409 and a link to the article is provided below (subscription to the journal required).

http://dx.doi.org/10.1021/ed101042y

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A Comprehensive Enzyme Kinetic Exercise for Biochemistry

The kinetics of the dephosphorylation of sodium p-nitrophenol using the enzyme bovine alkaline phosphatase is studied by measuring the reaction’s velocity spectrophotometrically as a function of the substrate’s concentration. The kinetic parameters Km and Vm are determined using Lineweaver-Burke and Eadie-Hofstee plots.

The full citation is here: Barton, J.  J. Chem. Educ. 2011, 88, 1336–1339 and a link to the article is provided below (subscription to the journal required).

http://dx.doi.org/10.1021/ed100816r

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Measurement of Solution Viscosity via Diffusion-Ordered NMR Spectrosocpy (DOSY)

In this experiment students use diffusion-ordered NMR spectroscopy (DOSY) to determine the viscosity of a solution by measuring the diffusion coefficient (D) for a reference compound in solvents of known viscosity (η), generating a linear calibration curve of log(D) vs log(η). Measuring the reference compound’s diffusion coefficient allows an determination of its viscosity.

The full citation is here: Li, W., Kagan, G., Hopson, R., Williard, P. G.  J. Chem. Educ. 2011, 88, 1331–1335 and a link to the article is provided below (subscription to the journal required).

http://dx.doi.org/10.1021/ed100941t

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Using a Flatbed Scanner to Measure Detergency

Using a flatbed scanner to measure the reflectance from samples of a white polyester fabric impregnated with linseed oil, students determine detergent efficiency. Scans of samples are stored as RGB (red, green, blue) coordinates and the blue channel used as the analytical signal. Detergent efficiencies for different amounts of sodium dodecyl sulfate are measured relative to a reference standard (a non-impregnated sample) and the sample before and after cleaning. Results are compared to reflectance measurements made using a conventional spectrometer.

The full citation is here: Poce-Fatou, J. A., Bethencourt, M., Moreno-Dorado, F. J., Palacios-Santander, J. M.  J. Chem. Educ. 2011, 88, 1314–1317 and a link to the article is provided below (subscription to the journal required).

http://dx.doi.org/10.1021/ed100635z

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Laboratory Inquiry for Determining the Chemical Composition of a Component in a Laboratory Detergent

Students determine the concentration of sodium sesquicarbonate in an alkaline laundry detergent though a combination of an acid-base titration and thermal gravimetry, both of the thermal decomposition and the decomposition by reaction with acid.

The full citation is here: Koga, N., Kimura, T., Shigedomi, K.  J. Chem. Educ. 2011, 88, 1309–1313 and a link to the article is provided below (subscription to the journal required).

http://dx.doi.org/10.1021/ed1011212

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To See the World in a Grain of Sand: Recognizing the Origin of the Sand Specimens by DRIFT and Multivariate Exploratory Analysis

Students use DRIFT spectra and multivariate analysis to characterize sands collected from different locations. A principal component analysis shows that the scores for the first and fourth principal component allows students to identify samples collected from different areas. The scores plot distinguishes between samples that are carbonate-rich and that are silicate-rich. For carbonate-rich samples, it is possible to distinguish between those that are dolomite-rich and those that are not; for the silicate-rich samples there is some separation between those samples rich in quartz and those rich in feldspar.

The full citation is here: De Lorenzi Pezzolo, A.  J. Chem. Educ. 2011, 88, 1304–1308 and a link to the article is provided below (subscription to the journal required).

http://dx.doi.org/10.1021/ed9000409

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The Shell Seeker: What is the Quantity of Shell in the Lido di Venezia Sand? A Calibration DRIFTS Experiment

This experiment uses a novel approach to introduce students to the method of standard additions. To approximate the contribution of shell fragments in sand collected from a beach (in this case, from the seashore at Lido di Venezia, Italy). After obtaining DRIFT spectra of the sand and a powdered seashell (a cockleshell in this case), students identify peaks that serve as markers of the shell’s principle component – CaCO3. Students then measure the response for the sand and the sand spiked with known quantities of the powdered shell.

The full citation is here: De Lorenzi Pezzolo, A.  J. Chem. Educ. 2011, 88, 1298–1303 and a link to the article is provided below (subscription to the journal required).

http://dx.doi.org/10.1021/ed100832e

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Have Biofuel, Will Travel: A Colorful Experiment and a Different Approach to Teach the Undergraduate Laboratory

This experiment describes a  quantitative UV-Vis analysis of mixtures of diesel/ethanol and diesel/biofuel based on the absorption of a solvochromatic probe dye. Students first synthesize the dye and then monitor the change in the dye’s λmax for different known mixtures, creating an empirical scale of solvent polarity. Mixtures containing unknown (to the student) mixtures of diesel/ethanol and diesel/biofuel are then analyzed using calibration curves of solvent polarity as a function of the concentration of ethanol or biofuel.

The full citation is here: El Seoud, O. A., Loffredo, C., Galgano, P. D., Sato, B. M., Reichardt, C.  J. Chem. Educ. 2011, 88, 1293–1297 and a link to the article is provided below (subscription to the journal required).

http://dx.doi.org/10.1021/ed1009464

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