Dan Sykes

Chemical Education

Research in the area of chemical education focuses on the development of curricula that combine fundamental skills building laboratory exercises, in which students work independently of each other, with research projects that engage students through group work and self-discovery. The laboratory exercises are designed to engage students in solving open-ended research problems that are challenging and involve most of the concepts covered in the course. Students must read the scientific literature, develop their own strategies for solving the problem, implement the plans, trouble-shoot the problems, revise the procedures, analyze the data, write-up the results, and defend their conclusions. Along with learning the chemistry, students will develop experience with computer-interfaced instrumentation, computer-assisted data acquisition, and manipulation of large data sets using computers. These are all crucially important skills that must be developed in students training to be scientists. In the process, the students develop their critical thinking skills, their ability to handle new problems, their group abilities, and develop accurate and precise laboratory techniques that are necessary for successful completion of the projects.

Our goal is to engage undergraduates in cutting edge scientific research through a very structured guided-inquiry learning experience with the hope that they will be stimulated to the point of pursuing careers in science or engineering.

A recent poll in the Journal of Chemical Education indicates that the percentage of instructional time spent on electronics in instrumental analysis courses has increased by 10% over the past ten years. This trend reflects the increase in sophistication of the analytical tools at our disposal, which requires a higher level of understanding to manipulate and troubleshoot instrumentation. In contrast, a majority of universities report that student interest in electronics is low and this attitude has an overwhelming influence (in a negative way) on course evaluations. This was certainly the case here at Penn State . In order to increase student interest in electronics and promote an appreciation for the practical applications of electronics in chemistry, electronics-based research projects have been introduced into the Instrumental Analysis courses (Separations/Electrochemistry and Spectroscopy courses). The projects require the students to build, from scratch, calibrated and quantitative instruments.  Past and Current projects:

1. Static solid-state deuterium NMR probe (NSF DUE-0341487)

2. Diamond-anvil cell

3. Gated- fluorimeter

4. Barcode scanner

5. GC-FID

6. Ion chromatography instrument

7. Dissolved oxygen probe

8. Cyclic voltammetry instrument

9. DNA oligomer sensor

10. UV-VIS grating-based photodiode array spectrometer

11. several more

Environmental /Forensic Chemistry

Rapid Field- and Laboratory-based Characterization of Explosives Residue with Application to Prediction and Remediation Technologies.

The vapor plume from an explosive may contain from as much as 1000 parts per million to fractions of a part per trillion of the molecular constituents, impurities, or decomposition products. Molecular spectroscopic techniques can be used to uniquely identify explosive molecules in the vapor phase, but the low vapor pressure of many explosives means that this will often not be feasible and require direct sampling, near-proximity instrumentation measurements. As such, the deployment of a number of portable field-based instruments is required to conduct rapid qualitative and quantitative screening of the explosive residue. Real-time characterization of an IED event can aid in correctly mapping the aerial extent of the explosive residue and the identification of chemical constituents and short-lived byproducts of the explosion. The overarching goal is to develop a set of rapid field-based quantitative systems that aid in the forensic collection and analysis of IED events. On-site analysis can aid field personnel in identifying the current types or categories of IEDs in use and facilitate real-time detection of other similar IEDs .

We have been successful in developing several field-based analytical methods for the quantification of chemicals used for environmental monitoring or are of environmental concern. The portable gated fluorimeter uses either a high-intensity UV-LED or a 532 nm diode laser as the excitation source, a concave holographic grating and a 102x1 linear optical array sensor. The instrument uses a time delay between the excitation pulse and signal acquisition. The gating electronics are fully adjustable and can be field adjusted to optimize sample signal. Currently, we have achieved sub-part per billion levels of detection for select compounds. The GC-FID is mobile but not fully configured for field applications. Samples are introduced via a sniffer and separation is achieved using a 1/8-inch outside diameter packed column. The GC can efficiently separate naphthalene from 1-methyl naphthalene.

Current research involves the modification of these instruments for use in explosives detection. Our initial efforts will focus on the measurement of the spectroscopic properties of the chemical constituents of explosive residue in order to optimize the source and timing characteristics for our devices. The spectroscopic data will not be limited to the fluorescent properties of these materials but also include photoacoustic and other vibrational methods. We plan to integrate quadrature detection into the design of the gated fluorimeter to enhance its directional capabilities. In addition, we plan to develop a hybrid instrument which integrates the fluorimeter -based detection system into the GC.

Al-Organic Acid Complexation : Water Chemistry of Aluminum.

Our research uses molecular orbital calculations, and NMR and ATR-FTIR spectroscopies to probe the interactions of organic molecules (oxalic, salicylic and formic acids, hydrocarbon derivatives, etc.) with oxide (silicate) surfaces with application to the diagenetic and hydrothermal alteration of clay and feldspar surfaces; to investigate the basis set dependency of Al chemical shieldings (calculated using the GIAO method) in aluminosilicate molecules and using the results to test Al speciation models for a wide range of materials ( magmatic glasses, zeolites , hydrothermal solutions). This work has shown that the energetics of absorption phenomena can be accurately predicted by only necessarily defining the first hydration shell around the absorbing species and that explicit inclusion of hydration shells are not necessary to accurately model the vibrational and NMR spectra of mineral surfaces with absorbed species. The findings greatly simplify the computational methods in these investigations. Further, this research has resolved a longstanding discrepancy in the interpretation of the pH-dependent organic acid complexation (oxalate, acetate, salicylate ) of the hexa aquo cation , Al(H₂O)₆³⁺, based on potentiometric and spectroscopic (NMR) information.

Silicate Glasses.

One example of our efforts has been to test the assignment of the peaks near 485 cm^-1 and 600 cm^-1 in the vibrational spectra of SiO₂-Mⁿ⁺_1/nAlO₂ (where M = an alkali or alkaline earth element) glasses to n_s(T-O-T) modes in four- and three-membered rings.  Force constant analyses of the potential energy minimized structures of cyclic [H₆Si_mAl_nO₉]^n- (m+n=3) and [H₈Si_mAl_nO_12]^n- (m+n=4), LiH₆Si₂AlO₉, Li₂H₈Si₂Al₂O₁₂ , Mg₂H₈Al₄O₁₂ molecules predict n_s(T-O-T) modes between 490 cm^-1 and 430 cm^-1 depending on the number of Al atoms in the negatively-charged four-membered rings and n_s(T-O-T) modes at 525 cm^-1 and 545 cm^-1 in Li₂H₈Si₂Al₂O₁₂ and Mg₂H₈Al₄O₁₂, respectively.  The theoretical frequency shift of the n_s(T-O-T) mode calculated for the (H₈Si_mAl_nO₁₂)^n- rings is consistent with the experimentally observed shifts of the 490-485 cm^-1 and the 495-515 cm^-1 peaks in glasses along the SiO₂-NaAlSiO₄ and SiO2-CaAl₂Si₂O₈ joins, respectively.  Similarly, there is a strong correlation between the theoretical breathing mode frequencies of the (H₆Si_mAl_nO₉)^n- molecules and the frequency of the 540-600 cm^-1 peak in fully-polymerized SiO₂-Mⁿ⁺_1/nAlO₂ glasses as a function of the Al/(Al+Si).  Intermediate range order in SiO₂- Mⁿ⁺_1/nAlO₂ glasses is interpreted in terms of changes in ring statistics.  In SiO₂ glass, the Raman peaks at 606 (D2), 495 (D1) and 430 cm^-1 correspond to three-, four-, and >four-membered rings, respectively.  The predominant low-frequency peak in the vibrational spectra of glasses along the SiO₂-NaAlSiO₄ and SiO₂-CaAl₂Si₂O₈ joins at 540-606 cm^-1 and 485-515 cm^-1 are ascribed to three- and four-membered rings, respectively.

Courses:

CHEM 13 – General Chemistry II ( Summer 2002, Spring 2004, Fall 2004)
CHEM 402 – Environmental Chemistry ( Fall semesters)
CHEM 425 – Separations and Electrochemistry ( Fall semesters)
CHEM 426 – Chemical Spectroscopy ( Spring semesters)
CHEM 427 – Forensic Chemistry (beginning Spring 2006)
CHEM 451 – Physical Chemistry (Spring 2002-2005)
CHEM 457 – Physical Chemistry Lab ( Fall 2001, Spring 2002, Fall 2002)

Future Courses:

CHEM 227 – Analytical Chemistry

CHEM/ENGL 2XX - Science, Culture, and the Nature of Matter 1880-1939 (Co-Instructor: Mark Morrisson ; cross-listed with English Dept.)