P959: Scalable laboratory report submission, grading, and feedback via Turnitin embedded in Desire2Learn [WITHDRAWN]

Author: J. Clay Harris, The Ohio State University, USA

Co-Author:

Date: 8/7/14

Time: 11:50 AM12:10 PM

Room: ASH 2302

Related Symposium: S23

Large laboratory courses are plagued with grading inequities even with well-established rubrics since multiple graders are required. Turnitin, a cloud based service for originality checking, online grading, and peer review, has partnered with Desire2Learn (D2L) to provide Originality Checking and GradeMark features into D2L’s familiar Dropbox tool. This presentation will illustrate the effectiveness of these tools in improving grading efficiency, reproducibility, and oversight as applied to quantitative and instrumental analysis while also demonstrating its utility in all chemistry courses with written assignments.

P857: Investigation of buffer systems in the quantitative analysis lab and Student exploration of three quantitative techniques for the analysis of an unknown solution [WITHDRAWN]

Author: J. Clay Harris, The Ohio State University, USA

Co-Author:

Date: 8/6/14

Time: 2:25 PM2:45 PM

Room: MAK B1120

Related Symposium: S57

Investigation of buffer systems in the quantitative analysis lab
The concept of equilibrium is challenging for many students, but considering polyprotic acid/base equilibria complete with activity, temperature effects, and water’s neutralizing abilities is a challenge for all but the most exceptional. This experiment allows students to investigate buffer systems starting from the simplest monoprotic examples both without and with activity corrections and progressing to the most difficult polyprotic buffers that are rather strongly activity and temperature dependent.

Student exploration of three quantitative techniques for the analysis of an unknown solution
Quantitative analysis experiments tend to be compartmentalized and used as examples of specific topics and techniques covered during the quantitative analysis lecture course. However, the analytical chemist will typically finalize the most critical decisions before any analysis is completed; the sample collection, preparation, and analysis methodology that greatly impacts the accuracy, precision, and cost of the results. A laboratory writing assignment has been devised to lead students through the thought process of the analytical chemist’s considerations. Students reflect upon their results from three determinations of [Cl] and [I] from the same unknown with potentiometry, ion-selective electrodes, and ion chromatography while considering a broad range of experimental attributes.

P710: Solid-supported azo dye arrays in the development of a colorimetric anion-selective indicator

Author: Noel M. Paul, The Ohio State University, USA

Co-Author: Benjamin P. Mohr, J. Clay Harris and Chris S. Callam, The Ohio State University, USA

Date: 8/6/14

Time: 10:35 AM10:55 AM

Room: LMH 114

Related Symposium: S51

Sophomore organic chemistry students have collaborated in the search for an azo dye that elicits a unique ionochromic effect in the presence of specific anions. As a complement to existing methods, colorimetric anion-selective indictors hold promise as a method to quickly quantitate threshold levels of toxic anions in both remote and economically depressed regions where analytical instrumentation is out of reach. Although this effect was previously identified through a screen of commercially available dyes, synthetic challenges have impeded the investigation of a related series of dyes whose aim is to elaborate the mechanism of this selective color change effect. Students functionalized cellulose chromatography paper with the assistance of microwave radiation, then conducted unique azo-coupling reactions following a specific grid pattern to yield 42 unique arrays. Each dye array was separated into three identical test strips, and these strips were subsequently exposed to acid, nitrate, or bromide. Using diffuse reflectance UV-vis spectroscopy, 630 full spectra were collected and the resulting data was complied and returned to the students for analysis. These results have suggested new single-molecule targets for future investigation. Following the study, the massive data set was processed using principal component analysis to reveal correlations difficult to detect through graphical means. Through their participation in this project, students earned insight into the difficulties and rewards inherit in the development of new knowledge, and using their results, this solid phase approach has been confirmed as an effective method to screen a large number of candidates for the development of anion-selective indicators.