@article{franzen_cochran_weng_bartolotti_delley_2016, title={The quadrapolar character of the Markovnikov reaction transition state}, volume={464}, ISSN={["1873-4421"]}, DOI={10.1016/j.chemphys.2015.11.001}, abstractNote={The properties of the transition states for the electrophilic addition reactions of four molecules of the type HX (X = Br, Cl, F and OH) to 1-propene form 2-X propane by the Markovnikov mechanism have been calculated using density functional theory (DFT). A comparative study of the transition state along the reaction path for both M and AM addition was studied in order to understand the origins of regioselectivity of H2O. The quadrapolar nature of the transition state is arises because of a sequential mechanism, in which the addition across the π-bond occurs in two steps, first H+ and then X−. The M reaction mechanism is consistent with a H+X− dipole which induces an oppositely polarized C1−C2+ dipole in the transition state, resulting in a quadrupole. The C1−C2+ dipole in the M mechanism is consistently larger than the C1+C2− dipole of the AM transition state for all species studied.}, journal={CHEMICAL PHYSICS}, author={Franzen, Stefan and Cochran, Kristin H. and Weng, James and Bartolotti, Libero and Delley, Bernard}, year={2016}, month={Jan}, pages={46–54} }
 @article{cochran_barry_robichaud_muddiman_2015, title={Analysis of trace fibers by IR-MALDESI imaging coupled with high resolving power MS}, volume={407}, ISSN={["1618-2650"]}, DOI={10.1007/s00216-014-8042-y}, abstractNote={Trace evidence is a significant portion of forensic cases. Textile fibers are a common form of trace evidence that are gaining importance in criminal cases. Currently, qualitative techniques that do not yield structural information are primarily used for fiber analysis, but mass spectrometry is gaining an increasing role in this field. Mass spectrometry yields more quantitative structural information about the dye and polymer that can be used for more conclusive comparisons. Matrix-assisted laser desorption electrospray ionization (MALDESI) is a hybrid ambient ionization source being investigated for use in mass spectrometric fiber analysis. In this manuscript, IR-MALDESI was used as a source for mass spectrometry imaging (MSI) of a dyed nylon fiber cluster and single fiber. Information about the fiber polymer as well as the dye were obtained from a single fiber which was on the order of 10 μm in diameter. These experiments were performed directly from the surface of a tape lift of the fiber with a background of extraneous fibers.}, number={3}, journal={ANALYTICAL AND BIOANALYTICAL CHEMISTRY}, author={Cochran, Kristin H. and Barry, Jeremy A. and Robichaud, Guillaume and Muddiman, David C.}, year={2015}, month={Jan}, pages={813–820} }
 @article{cochran_barry_muddiman_hinks_2013, title={Direct Analysis of Textile Fabrics and Dyes Using Infrared Matrix-Assisted Laser Desorption Electrospray Ionization Mass Spectrometry}, volume={85}, ISSN={["0003-2700"]}, DOI={10.1021/ac302519n}, abstractNote={The forensic analysis of textile fibers uses a variety of techniques from microscopy to spectroscopy. One such technique that is often used to identify the dye(s) within the fiber is mass spectrometry (MS). In the traditional MS method, the dye must be extracted from the fabric and the dye components are separated by chromatography prior to mass spectrometric analysis. Direct analysis of the dye from the fabric allows the omission of the lengthy sample preparation involved in extraction, thereby significantly reducing the overall analysis time. Herein, a direct analysis of dyed textile fabric was performed using the infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) source for MS. In MALDESI, an IR laser with wavelength tuned to 2.94 μm is used to desorb the dye from the fabric sample with the aid of water as the matrix. The desorbed dye molecules are then postionized by electrospray ionization (ESI). A variety of dye classes were analyzed from various fabrics with little to no sample preparation allowing for the identification of the dye mass and in some cases the fiber polymer. Those dyes that were not detected using MALDESI were also not observed by direct infusion ESI of the dye standard.}, number={2}, journal={ANALYTICAL CHEMISTRY}, author={Cochran, Kristin H. and Barry, Jeremy A. and Muddiman, David C. and Hinks, David}, year={2013}, month={Jan}, pages={831–836} }