@article{sui_feng_ankeny_vinueza_2022, title={Quantification of docusate antimicrobial finishing after simulated landfill degradation via tandem mass spectrometry and QuEChERS extraction}, volume={10}, ISSN={["1759-9679"]}, url={https://doi.org/10.1039/D2AY01153K}, DOI={10.1039/d2ay01153k}, abstractNote={Quantification of silver docusate antimicrobial finishing in soil by tandem mass spectrometry after QuEChERS extraction.}, journal={ANALYTICAL METHODS}, author={Sui, Xinyi and Feng, Chengcheng and Ankeny, Mary and Vinueza, Nelson R.}, year={2022}, month={Oct} }
 @article{millbern_trettin_wu_demmler_vinueza_2022, title={Synthetic dyes: A mass spectrometry approach and applications}, volume={11}, ISSN={["1098-2787"]}, DOI={10.1002/mas.21818}, abstractNote={Abstract}, journal={MASS SPECTROMETRY REVIEWS}, author={Millbern, Zoe and Trettin, Alison and Wu, Rachel and Demmler, Morgan and Vinueza, Nelson R.}, year={2022}, month={Nov} }
 @article{millbern_vinueza_2022, title={The characterization of disperse dyes in polyester fibers using DART mass spectrometry}, volume={9}, ISSN={["1556-4029"]}, DOI={10.1111/1556-4029.15129}, abstractNote={Abstract}, journal={JOURNAL OF FORENSIC SCIENCES}, author={Millbern, Zoe and Vinueza, Nelson R.}, year={2022}, month={Sep} }
 @article{umbuzeiro_morales_vacchi_albuquerque_szymczyk_sui_vinueza_freeman_2021, title={A promising Ames battery for mutagenicity characterization of new dyes}, volume={62}, ISSN={["1098-2280"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85097440491&partnerID=MN8TOARS}, DOI={10.1002/em.22417}, abstractNote={Abstract}, number={1}, journal={ENVIRONMENTAL AND MOLECULAR MUTAGENESIS}, author={Umbuzeiro, Gisela A. and Morales, Daniel A. and Vacchi, Francine I and Albuquerque, Anjaina F. and Szymczyk, Malgorzata and Sui, Xinyi and Vinueza, Nelson and Freeman, Harold S.}, year={2021}, month={Jan}, pages={52–65} }
 @article{marshburn_ashley_curtin_sultana_liu_vinueza_ison_jakubikova_2021, title={Are all charge-transfer parameters created equally? A study of functional dependence and excited-state charge-transfer quantification across two dye families}, volume={8}, ISSN={["1463-9084"]}, url={https://doi.org/10.1039/D1CP03383B}, DOI={10.1039/d1cp03383b}, abstractNote={Twenty dyes from the Max Weaver Dye Library were used to benchmark six commonly used DFT functionals to understand the interplay between the errors in the calculated excitation energies and the degree of charge transfer character of the excitations.}, journal={PHYSICAL CHEMISTRY CHEMICAL PHYSICS}, publisher={Royal Society of Chemistry (RSC)}, author={Marshburn, Richard Drew and Ashley, Daniel C. and Curtin, Gregory M. and Sultana, Nadia and Liu, Chang and Vinueza, Nelson R. and Ison, Elon A. and Jakubikova, Elena}, year={2021}, month={Aug} }
 @article{feng_sui_ankeny_vinueza_2021, title={Identification and quantification of CI Reactive Blue 19 dye degradation product in soil}, volume={137}, ISSN={["1478-4408"]}, url={https://doi.org/10.1111/cote.12527}, DOI={10.1111/cote.12527}, abstractNote={Abstract}, number={3}, journal={COLORATION TECHNOLOGY}, publisher={Wiley}, author={Feng, Chengcheng and Sui, Xinyi and Ankeny, Mary Ann and Vinueza, Nelson R.}, year={2021}, month={Jun}, pages={251–258} }
 @article{freeman_santos_chen_vendemiatti_oliveira_vacchi_vinueza_umbuzeiro_2021, title={Molecular characterization and ecotoxicological evaluation of the natural dye madder and its chlorinated products}, volume={11}, ISSN={["1614-7499"]}, DOI={10.1007/s11356-021-17388-4}, abstractNote={There has been increased interest in the use of natural dyes for textile coloration as alternatives to synthetic dyes, due to the general belief that natural dyes are more environmentally friendly. However, natural dyes have poor affinity for textiles, which can lead to high dye levels in the resultant wastewater. While chlorine treatment has proven to be effective for dye wastewater disinfection and decolorization, this process can also lead to the formation of more toxic degradation products for certain synthetic dyes. On the other hand, little information is available regarding the ecotoxicity of natural dyes and their chlorination products. To advance knowledge in this area, madder was selected due to its historical importance and wide application in the textile industry. Specifically, we sought to characterize the chlorine-induced degradation products of an aqueous madder solution and to assess their ecotoxicity. The main component of the present madder sample was Alizarin (89.8%). Chlorination led to complete decolorization, and 2-hydroxynaphthalene-1,4-dione and phthalic anhydride were identified as key degradation products. Chlorination of madder decreased toxicity to Daphnia similis (microcrustacean) 10-fold and removed the toxicity to Raphidocellis subcapitata (algae), when compared to the parent dye.}, journal={ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH}, author={Freeman, Harold S. and Santos, Tuane C. and Chen, Yufei and Vendemiatti, Josiane A. S. and Oliveira, Adria C. and Vacchi, Francine I. and Vinueza, Nelson R. and Umbuzeiro, Gisela A.}, year={2021}, month={Nov} }
 @article{liu_sui_terán_chapman_ankeny_vinueza_2021, title={Separation and identification of commercial reactive dyes with hydrophilic interaction liquid chromatography and quadrupole time‐of‐flight mass spectrometry}, volume={137}, ISSN={1472-3581 1478-4408}, url={http://dx.doi.org/10.1111/cote.12539}, DOI={10.1111/cote.12539}, abstractNote={Abstract}, number={4}, journal={Coloration Technology}, publisher={Wiley}, author={Liu, Yixin and Sui, Xinyi and Terán, Julio E. and Chapman, Lisa P. and Ankeny, Mary and Vinueza, Nelson R.}, year={2021}, month={Mar}, pages={407–417} }
 @article{terán_millbern_shao_sui_liu_demmler_vinueza_2020, title={Characterization of synthetic dyes for environmental and forensic assessments: A chromatography and mass spectrometry approach}, volume={44}, ISSN={1615-9306 1615-9314}, url={http://dx.doi.org/10.1002/jssc.202000836}, DOI={10.1002/jssc.202000836}, abstractNote={Abstract}, number={1}, journal={Journal of Separation Science}, publisher={Wiley}, author={Terán, Julio E and Millbern, Zoe and Shao, Dongyan and Sui, Xinyi and Liu, Yixin and Demmler, Morgan and Vinueza, Nelson R}, year={2020}, month={Nov}, pages={387–402} }
 @article{sultana_williams_ankeny_vinueza_2019, title={Degradation studies of CI Reactive Blue 19 on biodegraded cellulosic fabrics via liquid chromatography-photodiode array detection coupled to high resolution mass spectrometry}, volume={135}, ISSN={["1478-4408"]}, DOI={10.1111/cote.12440}, abstractNote={Abstract}, number={6}, journal={COLORATION TECHNOLOGY}, author={Sultana, Nadia and Williams, Kelsey and Ankeny, Mary and Vinueza, Nelson R.}, year={2019}, month={Dec}, pages={475–483} }
 @article{adams_vinueza_romanyuk_gordeev_paskova_ivanisevic_2019, title={Nanostructured GaOOH modified with reactive yellow, red and blue water-soluble dyes}, volume={9}, ISSN={["2158-3226"]}, DOI={10.1063/1.5080353}, abstractNote={Water soluble reactive dyes are used to modify nanostructured GaOOH. The resulting particles showed excellent stability in water solutions. The materials were characterized by Scanning electron microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) to assess changes due to the dye functionalization. SEM revealed changes in size after dye modification. XPS confirmed the presence of the dyes on the nanostructured materials and assessed changes in functional groups due to use of different type of modification and concentrations of dyes. The reported approach to stabilize the nanostructured GaOOH provides a simple and environmentally friendly route to tune the properties of wide band gap semiconductor materials.}, number={2}, journal={AIP ADVANCES}, author={Adams, W. Taylor and Vinueza, Nelson R. and Romanyuk, Oleksandr and Gordeev, Ivan and Paskova, Tania and Ivanisevic, Albena}, year={2019}, month={Feb} }
 @article{umbuzeiro_albuquerque_vacchi_szymczyk_sui_aalizadeh_ohe_thomaidis_vinueza_freeman_2019, title={Towards a reliable prediction of the aquatic toxicity of dyes}, volume={31}, ISSN={["2190-4715"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85074502142&partnerID=MN8TOARS}, DOI={10.1186/s12302-019-0258-1}, abstractNote={Abstract}, number={1}, journal={ENVIRONMENTAL SCIENCES EUROPE}, author={Umbuzeiro, Gisela de A. and Albuquerque, Anjaina F. and Vacchi, Francine I and Szymczyk, Malgorzata and Sui, Xinyi and Aalizadeh, Reza and Ohe, Peter C. and Thomaidis, Nikolaos S. and Vinueza, Nelson R. and Freeman, Harold S.}, year={2019}, month={Dec} }
 @article{kim_vinueza_kelley_park_2018, title={Correlation between solubility parameters and recovery of phenolic compounds from fast pyrolysis bio-oil by diesel extraction}, volume={1}, ISSN={2588-9133}, url={http://dx.doi.org/10.1016/j.crcon.2018.08.004}, DOI={10.1016/j.crcon.2018.08.004}, abstractNote={Fast pyrolysis bio-oils (fpBO) were extracted with two alternative commercial transportation fuels, hydrocarbon diesel and bio-diesel. The extraction of fpBO with commercial diesel fuel provided a yield of 4.3 wt%, but the yield increased significantly to 26.6 wt% when bio-diesel was the extractant. The molecular weight of fpBO before and after extraction were consistent with the loss of a more soluble, low molecular weight fraction from the crude fpBO. The relative energy difference (RED), based on the Hansen solubility parameter (HSP), is used to examine the extraction efficiency of specific compounds in the two different ‘solvents’. Differences in the RED values could be used to rationalize differences in the partitioning of common fpBO phenolics.}, number={3}, journal={Carbon Resources Conversion}, publisher={Elsevier BV}, author={Kim, Hoyong and Vinueza, Nelson R. and Kelley, Stephen S. and Park, Sunkyu}, year={2018}, month={Dec}, pages={238–244} }
 @article{sultana_liu_szymczyk_freeman_vinueza_2018, title={Dimerised heterobifunctional reactive dyes. Part 1: characterisation using quadrupole time-of-flight mass spectrometry}, volume={134}, ISSN={1472-3581}, url={http://dx.doi.org/10.1111/cote.12368}, DOI={10.1111/cote.12368}, abstractNote={As part of an approach to enhancing the efficiency of reactive dye adsorption on cellulosic fibres at low electrolyte levels, commercially available dyes were dimerised using hexamethylenediamine (HMDA) as a linking group. A key component of this work involved using high‐resolution mass spectrometry (HRMS) to characterise a group of polysulphonated heterobifunctional monochlorotriazine/vinyl sulphone reactive dyes (CI Reactive Yellow 176, CI Reactive Red 239, CI Reactive Blue 221, CI Reactive Red 194 and CI Reactive Blue 222) and their dimeric analogs. In this respect, dimeric dye ions of differently charged states were observed using HRMS‐negative electrospray ionisation in combination with quadrupole time‐of‐flight mass spectrometry. For example, HRMS showed that the HMDA‐linked reaction products were mixtures of the target (unhydrolysed) dimers, hydrolysed dimers, monoreacted products and hydrolysed unreacted dyes, with CI Reactive Yellow 176 and CI Reactive Red 194 producing the desired unhydrolysed dimers.}, number={6}, journal={Coloration Technology}, publisher={Wiley}, author={Sultana, Nadia and Liu, Yixin and Szymczyk, Malgorzata and Freeman, Harold S. and Vinueza, Nelson R.}, year={2018}, month={Aug}, pages={470–477} }
 @article{sultana_gunning_furst_garrard_dow_vinueza_2018, title={Direct analysis of textile dyes from trace fibers by automated microfluidics extraction system coupled with Q-TOF mass spectrometer for forensic applications}, volume={289}, ISSN={0379-0738}, url={http://dx.doi.org/10.1016/j.forsciint.2018.05.020}, DOI={10.1016/j.forsciint.2018.05.020}, abstractNote={Textile fiber is a common form of transferable trace evidence at the crime scene. Different techniques such as microscopy or spectroscopy are currently being used for trace fiber analysis. Dye characterization in trace fiber adds an important molecular specificity during the analysis. In this study, we performed a direct trace fiber analysis method via dye characterization by a novel automated microfluidics device (MFD) dye extraction system coupled with a quadrupole-time-of-flight (Q-TOF) mass spectrometer (MS). The MFD system used an in-house made automated procedure which requires only 10 μL of organic solvent for the extraction. The total extraction and identification time by the system is under 12 min. A variety of sulfonated azo and anthraquinone dyes were analyzed from ∼1 mm length nylon fiber samples. This methodology successfully characterized multiple dyes (≥3 dyes) from a single fiber thread. Additionally, it was possible to do dye characterization from single fibers with a diameter of ∼10 μm. The MFD-MS system was used for elemental composition and isotopic distribution analysis where MFD-MS/MS was used for structural characterization of dyes on fibers.}, journal={Forensic Science International}, publisher={Elsevier BV}, author={Sultana, Nadia and Gunning, Sean and Furst, Stephen J. and Garrard, Kenneth P. and Dow, Thomas A. and Vinueza, Nelson R.}, year={2018}, month={Aug}, pages={67–74} }
 @article{vinueza_jankiewicz_gallardo_nash_kenttämaa_2018, title={Effects of hydrogen bonding on the gas-phase reactivity of didehydroisoquinolinium cation isomers}, volume={20}, ISSN={1463-9076 1463-9084}, url={http://dx.doi.org/10.1039/C8CP03350A}, DOI={10.1039/c8cp03350a}, abstractNote={Two previously unreported isomeric biradicals with a 1,4-radical topology, the 1,5-didehydroisoquinolinium cation and the 4,8-didehydroisoquinolinium cation, and an additional, previously reported isomer, the 4,5-didehydroisoquinolinium cation, were studied to examine the importance of the exact location of the radical sites on their reactivities in the gas phase.}, number={33}, journal={Physical Chemistry Chemical Physics}, publisher={Royal Society of Chemistry (RSC)}, author={Vinueza, Nelson R. and Jankiewicz, Bartłomiej J. and Gallardo, Vanessa A. and Nash, John J. and Kenttämaa, Hilkka I.}, year={2018}, pages={21567–21572} }
 @article{boes_narron_park_vinueza_2018, title={Mass Spectrometry Exposes Undocumented Lignin-Carbohydrate Complexes in Biorefinery Pretreatment Stream}, volume={6}, ISSN={2168-0485 2168-0485}, url={http://dx.doi.org/10.1021/acssuschemeng.8b01986}, DOI={10.1021/acssuschemeng.8b01986}, abstractNote={The presence and effects of lignin–carbohydrate complexes (LCCs) in biorefinery processes are largely unknown. Recently identified in a significant hydrothermal pretreatment process stream (autohydrolyzate), these molecules likely influence not only downstream processing but also product purity and performance. However, without an understanding of their structures, it is impossible to analyze and cope with their effects. To identify and elucidate LCCs in autohydrolyzate, a new method employed chloride doping and tandem mass spectrometry. The results showed complexes ranging in mass from 326–714 Da with evidence of xylose and glucose units. Further analysis revealed lignin-like levels of unsaturation, considering the number of carbons present. These results suggest that, although the complexes contain one or two carbohydrate units, their primary structures are closer to lignin compounds. This method provides a glimpse into the structures of LCCs in a biorefinery process stream, laying the foundation for ea...}, number={8}, journal={ACS Sustainable Chemistry & Engineering}, publisher={American Chemical Society (ACS)}, author={Boes, Kelsey S. and Narron, Robert H. and Park, Sunkyu and Vinueza, Nelson R.}, year={2018}, month={Jul}, pages={10654–10659} }
 @article{boes_roberts_vinueza_2018, title={Rapid Quadrupole-Time-of-Flight Mass Spectrometry Method Quantifies Oxygen-Rich Lignin Compound in Complex Mixtures}, volume={29}, ISSN={["1879-1123"]}, DOI={10.1007/s13361-017-1847-0}, abstractNote={Complex mixture analysis is a costly and time-consuming task facing researchers with foci as varied as food science and fuel analysis. When faced with the task of quantifying oxygen-rich bio-oil molecules in a complex diesel mixture, we asked whether complex mixtures could be qualitatively and quantitatively analyzed on a single mass spectrometer with mid-range resolving power without the use of lengthy separations. To answer this question, we developed and evaluated a quantitation method that eliminated chromatography steps and expanded the use of quadrupole-time-of-flight mass spectrometry from primarily qualitative to quantitative as well. To account for mixture complexity, the method employed an ionization dopant, targeted tandem mass spectrometry, and an internal standard. This combination of three techniques achieved reliable quantitation of oxygen-rich eugenol in diesel from 300 to 2500 ng/mL with sufficient linearity (R2 = 0.97 ± 0.01) and excellent accuracy (percent error = 0% ± 5). To understand the limitations of the method, it was compared to quantitation attained on a triple quadrupole mass spectrometer, the gold standard for quantitation. The triple quadrupole quantified eugenol from 50 to 2500 ng/mL with stronger linearity (R2 = 0.996 ± 0.003) than the quadrupole-time-of-flight and comparable accuracy (percent error = 4% ± 5). This demonstrates that a quadrupole-time-of-flight can be used for not only qualitative analysis but also targeted quantitation of oxygen-rich lignin molecules in complex mixtures without extensive sample preparation. The rapid and cost-effective method presented here offers new possibilities for bio-oil research, including: (1) allowing for bio-oil studies that demand repetitive analysis as process parameters are changed and (2) making this research accessible to more laboratories. Graphical Abstract ᅟ.}, number={3}, journal={JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY}, author={Boes, Kelsey S. and Roberts, Michael S. and Vinueza, Nelson R.}, year={2018}, month={Mar}, pages={535–542} }
 @article{boes_narron_chen_park_vinueza_2017, title={Characterization of biofuel refinery byproduct via selective electrospray ionization tandem mass spectrometry}, volume={188}, ISSN={["1873-7153"]}, DOI={10.1016/j.fuel.2016.10.016}, abstractNote={To achieve economic viability, biorefineries need to increase efficiency through characterization of byproducts for the purpose of valorization. One such byproduct is the liquid stream produced after autohydrolysis pretreatment, autohydrolyzate liquor, which contains valuable organic derivatives of hemicellulose and lignin from biomass. To characterize the autohydrolysis liquor, we employed a novel method for such liquor analysis that uses electrospray ionization and ion dopants in combination with tandem mass spectrometry using a quadrupole–time-of-flight mass spectrometer. Electrospray expands current analysis of such liquors through softer ionization. Ion dopants provide for differentiation of the complex mixture components without requiring derivatization or preliminary separation. The dopants—ammonium chloride and sodium hydroxide—primarily target and enhance ionization of hemicellulosic or lignin derivative species, respectively, based on the species’ differing functionalities. Valuable structural information can be gleaned from these enhanced species by ion isolation and collision-activated dissociation (CAD), which reveals the presence of hemicellulosic or lignin derivative functionalities. These ionization techniques coupled with CAD enabled us to not only confirm the presence of low molecular weight ions, such as vanillin, as previously seen with gas chromatography-mass spectrometry but also expand the characterization to high molecular weight species. This expanded knowledge of the composition of autohydrolyzate liquor opens up the potential to develop lucrative co-products from this stream in a commercial biorefinery.}, journal={FUEL}, author={Boes, Kelsey S. and Narron, Robert H. and Chen, Yufei and Park, Sunkyu and Vinueza, Nelson R.}, year={2017}, month={Jan}, pages={190–196} }
 @article{umbuzeiro_szymczyk_li_chen_vendemiatti_de albuquerque_dos santos_maselli_kummrow_vinueza_et al._2017, title={Purification and characterization of three commercial phenylazoaniline disperse dyes}, volume={133}, ISSN={1472-3581}, url={http://dx.doi.org/10.1111/cote.12307}, DOI={10.1111/cote.12307}, abstractNote={Although tons of disperse dyes are used worldwile, little information on their ecotoxicity is available. While in silico models can be used to predict their ecotoxicity, experimental results from Daphnia can show significantly higher toxicity than predicted. Thus the objective of this work was to extend the knowledge base in this area by evaluating the ecotoxicity of three widely used disperse dyes and comparing the results to predicted values. Bearing in mind that generating ecotoxicity data on azo disperse dyes is complicated because they are not readily found as homogeneous compounds, we employed chromatographic methods to purify three commercially dyes C.I. Disperse Violet 93, Blue 291, and Blue 373 already found in the aquatic environment. No acute toxicity was observed for Daphnia similis. These results seems to be in general agreement when compared with ECOSAR predicted values. We hypothesize that differences in Kow values could explain the variations in results.}, number={6}, journal={Coloration Technology}, publisher={Wiley}, author={Umbuzeiro, Gisela A. and Szymczyk, Malgorzata and Li, Min and Chen, Yufei and Vendemiatti, Josiane A. S. and de Albuquerque, Anjaina F. and dos Santos, Amanda and Maselli, Bianca de S. and Kummrow, Fábio and Vinueza, Nelson R. and et al.}, year={2017}, month={Oct}, pages={513–518} }
 @article{kuenemann_szymczyk_chen_sultana_hinks_freeman_williams_fourches_vinueza_2017, title={Weaver's historic accessible collection of synthetic dyes: a cheminformatics analysis}, volume={8}, ISSN={["2041-6539"]}, DOI={10.1039/c7sc00567a}, abstractNote={The Max Weaver Dye Library is presented to the scientific community with a cheminformatics approach to enhance research opportunities with this unique collection of ∼98 000 vials of custom-made dyes.}, number={6}, journal={CHEMICAL SCIENCE}, author={Kuenemann, Melaine A. and Szymczyk, Malgorzata and Chen, Yufei and Sultana, Nadia and Hinks, David and Freeman, Harold S. and Williams, Antony J. and Fourches, Denis and Vinueza, Nelson R.}, year={2017}, month={Jun}, pages={4334–4339} }
 @book{dow_hinks_garrard_sohn_furst_li_gunning_vinueza_2016, title={Microfluidic System for Automated Dye Molecule Extraction and Detection for Forensic Fiber Identification}, author={Dow, T. and Hinks, D. and Garrard, K. and Sohn, A. and Furst, S. and Li, M. and Gunning, S. and Vinueza, N.}, year={2016}, month={May} }
 @article{vinueza_jankiewicz_gallardo_lafavers_desutter_nash_kenttaemaa_2016, title={Reactivity Controlling Factors for an Aromatic Carbon-Centered sigma,sigma,sigma-Triradical: The 4,5,8-Tridehydroisoquinolinium Ion}, volume={22}, ISSN={["1521-3765"]}, DOI={10.1002/chem.201502502}, abstractNote={Abstract}, number={2}, journal={CHEMISTRY-A EUROPEAN JOURNAL}, author={Vinueza, Nelson R. and Jankiewicz, Bartlomiej J. and Gallardo, Vanessa A. and LaFavers, Gregory Z. and DeSutter, Dane and Nash, John J. and Kenttaemaa, Hilkka I.}, year={2016}, month={Jan}, pages={809–815} }
 @book{benitez_2016, title={The Art of Color in Solving Mysteries and Crime}, institution={American Chemical Society}, author={Benitez, Nelson R.}, year={2016}, month={Oct} }
 @article{li_chen_2015, title={Analysis of Sulfonated Anthraquinone Dyes by Electrospray Ionization Quadrupole Time-of-flight Tandem Mass Spectrometry}, volume={06}, ISSN={2165-8064}, url={http://dx.doi.org/10.4172/2165-8064.1000236}, DOI={10.4172/2165-8064.1000236}, abstractNote={A tandem mass spectrometric method using a commercial quadrupole–time-of-flight (QTOF) mass spectrometer is described for the identification of sulfonated anthraquinone type dyes, having a 1-amino anthraquinone-2- sulfonate backbone. A total of 9 anthraquinone dye model compounds were evaporated and ionized via negative-ion electrospray ionization (ESI). Ionization of the sulfonated anthraquinone compounds primarily results in the formation of deprotonated molecules, [M-H]-. Once ionized, the ions were subjected to collision-activated dissociation (CAD). The type of neutral molecules or ions cleaved during CAD facilitates identification of the original compound. In most cases, a loss of 64 amu was observed for all dyes and was confirmed to be SO2 by high resolution mass spectrometry analysis. A unimolecular rearrangement of the sulfonate (SO3) group was triggered by CAD that allowed loss of SO2. Also, it was found that different group functionalities attached to the anthraquinone backbone (e.g., secondary aromatic amines and secondary alkyl amines) have specific fragmentation pathways that can be used to distinguish them under similar CAD conditions. For example, an anthraquinone having a secondary amine with an aromatic group attached to it (e.g., Acid Blue 25) can be differentiated from an anthraquinone having a secondary alkyl amine (e.g., Acid Blue 62) based on the product ions. The resultant fragmentation patterns could contribute to the identification of unknown dyes with similar chemical structures. The method was also successfully used in concert with targeted CAD for quantification purposes. The methodology presented here is the first stage in building a high resolution mass spectrometry dye database from the extensive uncatalogued Max Weaver Dye Library at North Carolina State University.}, number={01}, journal={Journal of Textile Science & Engineering}, publisher={OMICS Publishing Group}, author={Li, Min and Chen, Yufei}, year={2015} }
 @article{zhang_vinueza_datta_michielsen_2015, title={Functional dye as a comonomer in a water-soluble polymer}, volume={53}, ISSN={0887-624X}, url={http://dx.doi.org/10.1002/pola.27592}, DOI={10.1002/pola.27592}, abstractNote={ABSTRACT}, number={13}, journal={Journal of Polymer Science Part A: Polymer Chemistry}, publisher={Wiley}, author={Zhang, Wenwen and Vinueza, Nelson R. and Datta, Preeta and Michielsen, Stephen}, year={2015}, month={Mar}, pages={1594–1599} }
 @article{vinueza_kim_gallardo_mosier_abu-omar_carpita_kenttämaa_2015, title={Tandem mass spectrometric characterization of the conversion of xylose to furfural}, volume={74}, ISSN={0961-9534}, url={http://dx.doi.org/10.1016/j.biombioe.2014.10.012}, DOI={10.1016/j.biombioe.2014.10.012}, abstractNote={Thermal decomposition of xylose into furfural under acidic conditions has been studied using tandem mass spectrometry. Two different Brønsted acids, maleic and sulfuric acids, were used to demonstrate that varying the Brønsted acid does not affect the mechanism of the reaction. Two selectively labeled xylose molecules, 1-13C and 5-13C-xyloses, were examined to determine which carbon atom is converted to the aldehyde carbon in furfural. This can be done by using tandem mass spectrometry since collision-activated dissociation (CAD) of protonated unlabeled furfural results in the loss of CO from the aldehyde moiety. The loss of a neutral molecule with MW of 29 Da (13CO) was observed for protonated furfural derived from 1-13C-labeled xylose while the loss of a neutral molecule with MW of 28 Da (CO) was observed for protonated furfural derived from 5-13C labeled xylose. These results support the hypothesis that the mechanism of formation of furfural under mildly hot acidic conditions involves an intramolecular rearrangement of protonated xylose into the pyranose form rather than into an open-chain form.}, journal={Biomass and Bioenergy}, publisher={Elsevier BV}, author={Vinueza, Nelson R. and Kim, Eurick S. and Gallardo, Vanessa A. and Mosier, Nathan S. and Abu-Omar, Mahdi M. and Carpita, Nicholas C. and Kenttämaa, Hilkka I.}, year={2015}, month={Mar}, pages={1–5} }
 @article{vinueza_gallardo_klimek_carpita_kenttämaa_2013, title={Analysis of carbohydrates by atmospheric pressure chloride anion attachment tandem mass spectrometry}, volume={105}, ISSN={0016-2361}, url={http://dx.doi.org/10.1016/j.fuel.2012.08.012}, DOI={10.1016/j.fuel.2012.08.012}, abstractNote={The ability to characterize oligosaccharides directly in complex mixtures would greatly benefit many research efforts focused on the development of biofuels from lignocellulosic biomass. We report here on the utility of chloride anion attachment in atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) tandem mass spectrometry for MW determination and structural elucidation of several mono-, di- and oligosaccharides directly without sample pretreatment or derivatization. Chloride anion forms stable adducts with these sugars upon ESI or APCI, which can be readily identified due to the chlorine isotope pattern. Fragment anions or other product anions are usually not observed, which is beneficial for mixture analysis. Upon collisional activation in MS2 experiments, these adducts readily lose HCl, which helps verify the molecular weight of each analyte. Isolating the resulting anion and subjecting it to further collision-activated dissociation experiments (MSn; n = 3–4) until no ion signal remains yields useful structural information. Examination of equimolar mixtures of mono-, di- and oligosaccharides and mixtures of enzymatically digested biomass demonstrates the ability of this methodology to ionize all the components of the mixtures without bias and with nearly equal efficiency.}, journal={Fuel}, publisher={Elsevier BV}, author={Vinueza, Nelson R. and Gallardo, Vanessa A. and Klimek, John F. and Carpita, Nicholas C. and Kenttämaa, Hilkka I.}, year={2013}, month={Mar}, pages={235–246} }
 @article{vinueza_gallardo_klimek_carpita_kenttämaa_2013, title={Analysis of xyloglucans by ambient chloride attachment ionization tandem mass spectrometry}, volume={98}, ISSN={0144-8617}, url={http://dx.doi.org/10.1016/j.carbpol.2013.06.070}, DOI={10.1016/j.carbpol.2013.06.070}, abstractNote={Xyloglucan oligomers obtained upon enzyme digestion from Hymenaea courbaril, Arabidopsis Columbia-0 and mur3 were ionized and analyzed by using chloride anion attachment electrospray ionization (ESI) and tandem mass spectrometry. MW determination and structural elucidation of several xyloglucan oligomers was performed directly from the mixture solutions without sample pretreatment or derivatization. Sodium cation attachment was used to determine the number of xyloglucans present in the mixtures and their MWs. However, tandem mass spectrometry results showed that structure elucidation based on the sodium adducts is ambiguous. Chloride anion also forms stable adducts with these xyloglucans upon ESI. These adducts can be readily identified due to the chlorine isotope pattern. The mass spectral profile of xyloglucans obtained for the mixtures matches the HPAEC results, thus validating this methodology for the determination of the xyloglucan composition and the MW of each xyloglucan. Upon collisional activation in MS2 experiments, the chloride anion adducts readily lose HCl, which helps verify the molecular weight of each xyloglucan. Isolating the resulting anion (deprotonated oligomer) and subjecting it to further collision-activated dissociation experiments (MSn; n = 3–4) yields useful structural information that allows the differentiation between isomeric anions and hence determination of the sequence of the xyloglucan oligomers. The deprotonated oligomers fragment by a stepwise loss of sugar units from the reducing end.}, number={1}, journal={Carbohydrate Polymers}, publisher={Elsevier BV}, author={Vinueza, Nelson R. and Gallardo, Vanessa A. and Klimek, John F. and Carpita, Nicholas C. and Kenttämaa, Hilkka I.}, year={2013}, month={Oct}, pages={1203–1213} }
 @article{jankiewicz_vinueza_kirkpatrick_gallardo_li_nash_kenttämaa_2013, title={Does the 2,6-didehydropyridinium cation exist?}, volume={26}, ISSN={0894-3230}, url={http://dx.doi.org/10.1002/poc.3120}, DOI={10.1002/poc.3120}, abstractNote={Reactive intermediates are key species involved in many chemical and biochemical processes. For example, carbon‐centered aromatic σ,σ‐biradicals formed in biological systems from naturally occurring enediyne antitumor antibiotics are responsible for the irreversible cleavage of double‐stranded DNA caused by these prodrugs. However, because of their high reactivity, it is very difficult or impossible to isolate and investigate these biradicals. The aromatic σ,σ‐biradical, 2,6‐didehydropyridine, has been speculated for many years to be formed in certain organic reactions; however, no definitive proof of its generation has been obtained. We report here the successful generation of protonated 2,6‐didehydropyridine and the examination of its chemical properties in the gas phase by using a Fourier transform ion cyclotron resonance mass spectrometer. The results suggest that a mixture of singlet (ground) state and triplet (excited) state 2,6‐didehydropyridinium cations was generated. The two different states show qualitatively different reactivity, with the triplet state showing greater Brønsted acidity than that of the singlet state. The triplet state also shows much greater radical reactivity than that of the singlet state, as expected because of the coupling of the nonbonding electrons in the singlet state. Copyright © 2013 John Wiley & Sons, Ltd.}, number={9}, journal={Journal of Physical Organic Chemistry}, publisher={Wiley}, author={Jankiewicz, Bartłomiej J. and Vinueza, Nelson R. and Kirkpatrick, Lindsey M. and Gallardo, Vanessa A. and Li, Guannan and Nash, John J. and Kenttämaa, Hilkka I.}, year={2013}, month={Jun}, pages={707–714} }
 @article{kirkpatrick_vinueza_jankiewicz_gallardo_archibold_nash_kenttämaa_2013, title={Experimental and Computational Studies on the Formation of Threepara-Benzyne Analogues in the Gas Phase}, volume={19}, ISSN={0947-6539}, url={http://dx.doi.org/10.1002/chem.201203264}, DOI={10.1002/chem.201203264}, abstractNote={Abstract}, number={27}, journal={Chemistry - A European Journal}, publisher={Wiley}, author={Kirkpatrick, Lindsey M. and Vinueza, Nelson R. and Jankiewicz, Bartłomiej J. and Gallardo, Vanessa A. and Archibold, Enada F. and Nash, John J. and Kenttämaa, Hilkka I.}, year={2013}, month={May}, pages={9022–9033} }
 @article{hurt_degenstein_gawecki_borton ii_vinueza_yang_agrawal_delgass_ribeiro_kenttämaa_2013, title={On-Line Mass Spectrometric Methods for the Determination of the Primary Products of Fast Pyrolysis of Carbohydrates and for Their Gas-Phase Manipulation}, volume={85}, ISSN={0003-2700 1520-6882}, url={http://dx.doi.org/10.1021/ac402380h}, DOI={10.1021/ac402380h}, abstractNote={Mass spectrometric methodology was developed for the determination and manipulation of the primary products of fast pyrolysis of carbohydrates. To determine the true primary pyrolysis products, a very fast heating pyroprobe was coupled to a linear quadrupole ion trap mass spectrometer through a custom-built adaptor. A home-built flow tube that simulates pyrolysis reactor conditions was used to examine the secondary reactions of the primary products. Depending on the experiment, the pyrolysis products were either evaporated and quenched or allowed to react for a period of time. The quenched products were ionized in an atmospheric pressure chemical ionization (APCI) source infused with one of two ionization reagents, chloroform or ammonium hydroxide, to aid in ionization. During APCI in negative ion mode, chloroform produces chloride anions that are known to readily add to carbohydrates with little bias and little to no fragmentation. On the other hand, in positive ion mode APCI, ammonium hydroxide forms ammonium adducts with carbohydrates with little to no fragmentation. The latter method ionizes compounds that are not readily ionized upon negative ion mode APCI, such as furan derivatives. Six model compounds were studied to verify the ability of the ionization methods to ionize known pyrolysis products: glycolaldehyde, hydroxyacetone, furfural, 5-hydroxymethylfurfural, levoglucosan, and cellobiosan. The method was then used to examine fast pyrolysis of cellobiose. The primary fast pyrolysis products were determined to consist of only a handful of compounds that quickly polymerize to form anhydro-oligosaccharides when allowed to react at high temperatures for an extended period of time.}, number={22}, journal={Analytical Chemistry}, publisher={American Chemical Society (ACS)}, author={Hurt, Matthew R. and Degenstein, John C. and Gawecki, Piotr and Borton II, David J. and Vinueza, Nelson R. and Yang, Linan and Agrawal, Rakesh and Delgass, W. Nicholas and Ribeiro, Fabio H. and Kenttämaa, Hilkka I.}, year={2013}, month={Nov}, pages={10927–10934} }
 @article{jankiewicz_vinueza_reece_lee_williams_nash_kenttämaa_2012, title={Effects of a Hydroxyl Substituent on the Reactivity of the 2,4,6-Tridehydropyridinium Cation, an Aromatic σ,σ,σ-Triradical}, volume={18}, ISSN={0947-6539}, url={http://dx.doi.org/10.1002/chem.201102641}, DOI={10.1002/chem.201102641}, abstractNote={Abstract}, number={3}, journal={Chemistry - A European Journal}, publisher={Wiley}, author={Jankiewicz, Bartłomiej J. and Vinueza, Nelson R. and Reece, Jennifer N. and Lee, Young C. and Williams, Peggy and Nash, John J. and Kenttämaa, Hilkka I.}, year={2012}, month={Jan}, pages={969–974} }
 @article{amundson_gallardo_vinueza_owen_reece_habicht_fu_shea_mossman_kenttämaa_2012, title={Identification and Counting of Oxygen Functionalities and Alkyl Groups of Aromatic Analytes in Mixtures by Positive-Mode Atmospheric Pressure Chemical Ionization Tandem Mass Spectrometry Coupled with High-Performance Liquid Chromatography}, volume={26}, ISSN={0887-0624 1520-5029}, url={http://dx.doi.org/10.1021/ef2019098}, DOI={10.1021/ef2019098}, abstractNote={A tandem mass spectrometric method using a commercial linear quadrupole ion trap (LQIT) mass spectrometer and another LQIT coupled with a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer is described for the identification and counting of different oxygen-containing functionalities and alkyl groups in unknown aromatic analytes. A total of 64 aromatic model compounds were evaporated and ionized via positive-mode atmospheric pressure chemical ionization (APCI). Ionization of the model compounds primarily results in the formation of protonated molecules, [M + H]+. In some cases, the molecular radical cation, [M]+ •, and/or a fragment ion, [M – H]+, are formed instead. Only in one case, no ions were observed near the m/z value of the molecular ion, and the ion with the greatest m/z value is a fragment ion, [M + H – H2O]+. Once ionized, the ions were subjected to multiple isolation and collision-activated dissociation (CAD) events until no more fragmentation was observed (up to MS5). In mos...}, number={5}, journal={Energy & Fuels}, publisher={American Chemical Society (ACS)}, author={Amundson, Lucas M. and Gallardo, Vanessa A. and Vinueza, Nelson R. and Owen, Benjamin C. and Reece, Jennifer N. and Habicht, Steven C. and Fu, Mingkun and Shea, Ryan C. and Mossman, Allen B. and Kenttämaa, Hilkka I.}, year={2012}, month={Apr}, pages={2975–2989} }
 @article{gallardo_jankiewicz_vinueza_nash_kenttämaa_2012, title={Reactivity of a σ,σ,σ,σ-Tetraradical: The 2,4,6-Tridehydropyridine Radical Cation}, volume={134}, ISSN={0002-7863 1520-5126}, url={http://dx.doi.org/10.1021/ja209068z}, DOI={10.1021/ja209068z}, abstractNote={The 2,4,6-tridehydropyridine radical cation, an analogue of the elusive 1,2,3,5-tetradehydrobenzene, was generated in the gas phase and its reactivity examined. Surprisingly, the tetraradical was found not to undergo radical reactions. This behavior is rationalized by resonance structures hindering fast radical reactions. This makes the cation highly electrophilic, and it rapidly reacts with many nucleophiles by quenching the N-C ortho-benzyne moiety, thereby generating a relatively unreactive meta-benzyne analogue.}, number={4}, journal={Journal of the American Chemical Society}, publisher={American Chemical Society (ACS)}, author={Gallardo, Vanessa A. and Jankiewicz, Bartłomiej J. and Vinueza, Nelson R. and Nash, John J. and Kenttämaa, Hilkka I.}, year={2012}, month={Jan}, pages={1926–1929} }
 @article{vinueza_archibold_jankiewicz_gallardo_habicht_aqueel_nash_kenttämaa_2012, title={Reactivity of the 4,5-Didehydroisoquinolinium Cation}, volume={18}, ISSN={0947-6539}, url={http://dx.doi.org/10.1002/chem.201103628}, DOI={10.1002/chem.201103628}, abstractNote={Abstract}, number={28}, journal={Chemistry - A European Journal}, publisher={Wiley}, author={Vinueza, Nelson R. and Archibold, Enada F. and Jankiewicz, Bartłomiej J. and Gallardo, Vanessa A. and Habicht, Steven C. and Aqueel, Mohammad Sabir and Nash, John J. and Kenttämaa, Hilkka I.}, year={2012}, month={Jun}, pages={8692–8698} }
 @article{jankiewicz_gao_reece_vinueza_narra_nash_kenttämaa_2012, title={Substituent Effects on the Nonradical Reactivity of 4-Dehydropyridinium Cation}, volume={116}, ISSN={1089-5639 1520-5215}, url={http://dx.doi.org/10.1021/jp2101557}, DOI={10.1021/jp2101557}, abstractNote={Recent studies have shown that the reactivity of the 4-dehydropyridinium cation significantly differs from the reactivities of its isomers toward tetrahydrofuran. While only hydrogen atom abstraction was observed for the 2- and 3-dehydropyridinium cations, nonradical reactions were observed for the 4-isomer. In order to learn more about these reactions, the gas-phase reactivities of the 4-dehydropyridinium cation and several of its derivatives toward tetrahydrofuran were investigated in a Fourier transform ion electron resonance mass spectrometer. Both radical and nonradical reactions were observed for most of these positively charged radicals. The major parameter determining whether nonradical reactions occur was found to be the electron affinity of the radicals--only those with relatively high electron affinities underwent nonradical reactions. The reactivities of the monoradicals are also affected by hydrogen bonding and steric effects.}, number={12}, journal={The Journal of Physical Chemistry A}, publisher={American Chemical Society (ACS)}, author={Jankiewicz, Bartłomiej J. and Gao, Jinshan and Reece, Jennifer N. and Vinueza, Nelson R. and Narra, Padmaja and Nash, John J. and Kenttämaa, Hilkka I.}, year={2012}, month={Mar}, pages={3089–3093} }
 @article{habicht_vinueza_amundson_kenttämaa_2011, title={Comparison of Functional Group Selective Ion–Molecule Reactions of Trimethyl Borate in Different Ion Trap Mass Spectrometers}, volume={22}, ISSN={1044-0305 1879-1123}, url={http://dx.doi.org/10.1007/s13361-010-0050-3}, DOI={10.1007/s13361-010-0050-3}, abstractNote={We report here a comparison of the use of diagnostic ion-molecule reactions for the identification of oxygen-containing functional groups in Fourier-transform ion cyclotron resonance (FTICR) and linear quadrupole ion trap (LQIT) mass spectrometers. The ultimate goal of this research is to be able to identify functionalities in previously unknown analytes by using many different types of mass spectrometers. Previous work has focused on the reactions of various boron reagents with protonated oxygen-containing analytes in FTICR mass spectrometers. By using a LQIT modified to allow the introduction of neutral reagents into the helium buffer gas, this methodology has been successfully implemented to this type of an ion trap instrument. The products obtained from the reactions of trimethyl borate (TMB) with various protonated analytes are compared for the two instruments. Finally, the ability to integrate these reactions into LC-MS experiments on the LQIT is demonstrated.}, number={3}, journal={Journal of The American Society for Mass Spectrometry}, publisher={Springer Science and Business Media LLC}, author={Habicht, Steve C. and Vinueza, Nelson R. and Amundson, Lucas M. and Kenttämaa, Hilkka I.}, year={2011}, month={Feb}, pages={520–530} }
 @article{habicht_vinueza_duan_fu_kenttämaa_2010, title={Data-dependent neutral gain MS3: Toward automated identification of the N-Oxide functional group in drug metabolites}, volume={21}, ISSN={1044-0305 1879-1123}, url={http://dx.doi.org/10.1016/j.jasms.2009.12.015}, DOI={10.1016/j.jasms.2009.12.015}, abstractNote={We report here an automated method for the identification of N-oxide functional groups in drug metabolites by using the combination of liquid chromatography/tandem mass spectrometry (LC/MSn) based on ion-molecule reactions and collision-activated dissociation (CAD). Data-dependent acquisition, which has been readily utilized for metabolite characterization using CAD-based methods, is adapted for use with ion-molecule reaction-based tandem mass spectrometry by careful choice of select experimental parameters. Two different experiments utilizing ion-molecule reactions are demonstrated, data-dependent neutral gain MS3 and data-dependent neutral gain pseudo-MS3, both of which generate functional group selective mass spectral data in a single experiment and facilitate increased throughput in structural elucidation of unknown mixture components. Initial results have been generated by using an LC/MSn method based on ion-molecule reactions developed earlier for the identification of the N-oxide functional group in pharmaceutical samples, a notoriously difficult functional group to identify via CAD alone. Since commercial software and straightforward, external instrument modification are used, these experiments are readily adaptable to the industrial pharmaceutical laboratory.}, number={4}, journal={Journal of the American Society for Mass Spectrometry}, publisher={Springer Nature}, author={Habicht, Steven C. and Vinueza, Nelson R. and Duan, Penggao and Fu, Mingkun and Kenttämaa, Hilkka I.}, year={2010}, month={Apr}, pages={559–563} }
 @article{habicht_amundson_duan_vinueza_kenttämaa hilkka i._2010, title={Laser-Induced Acoustic Desorption Coupled with a Linear Quadrupole Ion Trap Mass Spectrometer}, volume={82}, ISSN={0003-2700 1520-6882}, url={http://dx.doi.org/10.1021/ac901943k}, DOI={10.1021/ac901943k}, abstractNote={In recent years, laser-induced acoustic desorption (LIAD) coupled with a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer has been demonstrated to provide a valuable technique for the analysis of a wide variety of nonvolatile, thermally labile compounds, including analytes that could not previously be analyzed by mass spectrometry. Although FT-ICR instruments are very powerful, they are also large and expensive and, hence, mainly used as research instruments. In contrast, linear quadrupole ion trap (LQIT) mass spectrometers are common due to several qualities that make these instruments attractive for both academic and industrial settings, such as high sensitivity, large dynamic range, and experimental versatility. Further, the relatively small size of the instruments, comparatively low cost, and the lack of a magnetic field provide some distinct advantages over FT-ICR instruments. Hence, we have coupled the LIAD technique with a commercial LQIT, the Thermo Fischer Scientific LTQ mass spectrometer. The LQIT was modified for a LIAD probe by outfitting the removable back plate of the instrument with a 6 in. ConFlat flange (CFF) port, gate valve, and sample lock. Reagent ions were created using the LQIT's atmospheric pressure ionization source and trapped in the mass analyzer for up to 10 s to allow chemical ionization reactions with the neutral molecules desorbed via LIAD. These initial experiments focused on demonstrating the feasibility of performing LIAD in the LQIT. Hence, the results are compared to those obtained using an FT-ICR mass spectrometer. Despite the lower efficiency in the transfer of desorbed neutral molecules into the ion trap, and the smaller maximum number of available laser pulses, the intrinsically higher sensitivity of the LQIT resulted in a higher sensitivity relative to the FT-ICR.}, number={2}, journal={Analytical Chemistry}, publisher={American Chemical Society (ACS)}, author={Habicht, Steven C. and Amundson, Lucas M. and Duan, Penggao and Vinueza, Nelson R. and Kenttämaa Hilkka I.}, year={2010}, month={Jan}, pages={608–614} }
 @article{habicht_duan_vinueza_fu_kenttämaa_2010, title={Liquid chromatography/tandem mass spectrometry utilizing ion-molecule reactions and collision-activated dissociation for the identification of N-oxide drug metabolites}, volume={51}, ISSN={0731-7085}, url={http://dx.doi.org/10.1016/j.jpba.2009.09.047}, DOI={10.1016/j.jpba.2009.09.047}, abstractNote={A liquid chromatography/tandem mass spectrometry (LC/MS3) method based on ion-molecule reactions and collision-activated dissociation (CAD) is presented for the identification of analytes with the N-oxide functional group directly in mixtures. Tri(dimethylamino)borane (TDMAB) rapidly and selectively derivatizes protonated N-oxides in a modified commercial linear quadrupole ion trap (LQIT) mass spectrometer to yield a distinct product ion (adduct—(CH3)2NH). The LQIT was outfitted with an external reagent-mixing manifold that allows TDMAB to be mixed with the helium buffer gas used in the trap. The derivatized analytes are readily identified on the basis of a shift of 98 Th (Thomson) relative to the m/z value of the protonated analyte. Further probing of the derivatized analytes via isolation followed by CAD can be used to confirm the presence of an N-oxide, and distinguish between aliphatic and aromatic tertiary N-oxides. Since the ion-molecule reaction is fast, these experiments can be accomplished on the same time scale as typical CAD-based MSn experiments, thus maintaining the duty cycle of the instrument for this type of experiment. To demonstrate real world applicability, the method was tested on real active pharmaceutical ingredients and their derivatives.}, number={4}, journal={Journal of Pharmaceutical and Biomedical Analysis}, publisher={Elsevier BV}, author={Habicht, Steven C. and Duan, Penggao and Vinueza, Nelson R. and Fu, Mingkun and Kenttämaa, Hilkka I.}, year={2010}, month={Mar}, pages={805–811} }
 @article{yang_nash_yurkovich_jin_vinueza_kenttämaa_2008, title={Gas-Phase Reactivity of Aromatic σ,σ-Biradicals toward Dinucleoside Phosphates}, volume={10}, ISSN={1523-7060 1523-7052}, url={http://dx.doi.org/10.1021/ol800312g}, DOI={10.1021/ol800312g}, abstractNote={In order to improve the understanding of the interactions of aromatic sigma,sigma-biradicals with DNA, the reactivity of three isomeric sigma,sigma-biradicals toward four dinucleoside phosphates was studied in a mass spectrometer. The dinucleoside phosphates were evaporated into the mass spectrometer by using laser-induced acoustic desorption (LIAD). The results demonstrate that the structure of the sigma,sigma-biradical and the base sequence of the dinucleoside phosphate can have a major influence on these reactions.}, number={10}, journal={Organic Letters}, publisher={American Chemical Society (ACS)}, author={Yang, Linan and Nash, John J. and Yurkovich, Michael J. and Jin, Zhicheng and Vinueza, Nelson R. and Kenttämaa, Hilkka I.}, year={2008}, month={May}, pages={1889–1892} }
 @article{habicht_vinueza_archibold_duan_kenttämaa_2008, title={Identification of the Carboxylic Acid Functionality by Using Electrospray Ionization and Ion−Molecule Reactions in a Modified Linear Quadrupole Ion Trap Mass Spectrometer}, volume={80}, ISSN={0003-2700 1520-6882}, url={http://dx.doi.org/10.1021/ac800002h}, DOI={10.1021/ac800002h}, abstractNote={A mass spectrometric method has been developed for the identification of the carboxylic acid functional group in analytes evaporated and ionized by electrospray ionization (ESI). This method is based on gas-phase ion-molecule reactions of ammoniated ([M + NH4]+) and sodiated ([M + Na]+) analyte molecules with trimethyl borate (TMB) in a modified linear quadrupole ion trap mass spectrometer. The diagnostic reaction involves addition of the deprotonated analyte to TMB followed by the elimination of methanol. A variety of analytes with different func-tionalities were examined, and this reaction was only observed for molecules containing the carboxylic acid functionality. The selectivity of the reaction is attributed to the acidic hydrogen present in the carboxylic acid group, which provides the proton necessary for the elimination of methanol. The diagnostic products are easily identified based on the m/z value of the product ion, which is 72 Th (thomson) greater than the m/z value of the charged analyte, and also by the character-istic isotope pattern of boron. The applicability of this method for pharmaceutical analysis was demonstrated for three nonsteroidal anti-inflammatory drugs: ibuprofen, naproxen, and ketoprofen.}, number={9}, journal={Analytical Chemistry}, publisher={American Chemical Society (ACS)}, author={Habicht, Steven C. and Vinueza, Nelson R. and Archibold, Enada F. and Duan, Penggao and Kenttämaa, Hilkka I.}, year={2008}, month={May}, pages={3416–3421} }
 @article{jankiewicz_reece_vinueza_nash_kenttämaa_2008, title={Reactivity of the 3,4,5-Tridehydropyridinium Cation-An Aromatic σ,σ,σ-Triradical}, volume={120}, ISSN={0044-8249 1521-3757}, url={http://dx.doi.org/10.1002/ange.200802714}, DOI={10.1002/ange.200802714}, abstractNote={Unterschiedliche Angriffspunkte: Studien zur Reaktivität des 3,4,5-Tridehydropyridiniumkations mithilfe eines Fourier-Transformations-Ionencyclotronresonanz-Massenspektrometers belegen, dass bei radikalischen Reaktionen zuerst über C3 Bindungen gebildet werden, bei nichtradikalischen Reaktionen über C3 oder C4 (siehe Schema). Das stärker Brønsted-saure isomere Kation 2,4,6-Tridehydropyridinium verhält sich anders, weil die meta-Benz-in-Positionen weniger reaktiv sind.}, number={51}, journal={Angewandte Chemie}, publisher={Wiley}, author={Jankiewicz, Bartłomiej J. and Reece, Jennifer N. and Vinueza, Nelson R. and Nash, John J. and Kenttämaa, Hilkka I.}, year={2008}, month={Dec}, pages={10008–10013} }
 @article{jankiewicz_reece_vinueza_nash_kenttämaa_2008, title={Reactivity of the 3,4,5-Tridehydropyridinium Cation-An Aromatic σ,σ,σ-Triradical}, volume={47}, ISSN={1433-7851 1521-3773}, url={http://dx.doi.org/10.1002/anie.200802714}, DOI={10.1002/anie.200802714}, abstractNote={Seeing the sites: Reactivity studies on the σ,σ,σ-triradical 3,4,5-tridehydropyridinium cation by using a Fourier transform ion cyclotron resonance mass spectrometer show that bond formation first occurs at C3 for radical reactions, and at either C3 or C4 for nonradical reactions (see scheme). The isomeric 2,4,6-tridehydropyridinium cation shows different chemical properties because of the lower reactivity of its meta-benzyne group(s) and its greater Brønsted acidity.}, number={51}, journal={Angewandte Chemie International Edition}, publisher={Wiley}, author={Jankiewicz, Bartłomiej J. and Reece, Jennifer N. and Vinueza, Nelson R. and Nash, John J. and Kenttämaa, Hilkka I.}, year={2008}, month={Dec}, pages={9860–9865} }
 @article{fu_duan_li_habicht_pinkston_vinueza_kenttämaa_2008, title={Regioselective ion–molecule reactions for the mass spectrometric differentiation of protonated isomeric aromatic diamines}, volume={133}, ISSN={0003-2654 1364-5528}, url={http://dx.doi.org/10.1039/b801961d}, DOI={10.1039/b801961d}, abstractNote={A mass spectrometric method utilizing regioselective ion-molecule reactions has been developed for the differentiation of protonated isomeric aromatic diamines in FT-ICR, linear quadrupole ion trap and triple quadrupole mass spectrometers.}, number={4}, journal={The Analyst}, publisher={Royal Society of Chemistry (RSC)}, author={Fu, Mingkun and Duan, Penggao and Li, Sen and Habicht, Steven C. and Pinkston, David S. and Vinueza, Nelson R. and Kenttämaa, Hilkka I.}, year={2008}, pages={452} }
 @article{jankiewicz_adeuya_yurkovich_vinueza_gardner_zhou_nash_kenttämaa_2007, title={Reactivity of an Aromatic σ,σ,σ-Triradical: The 2,4,6-Tridehydropyridinium Cation}, volume={119}, ISSN={0044-8249 1521-3757}, url={http://dx.doi.org/10.1002/ange.200701732}, DOI={10.1002/ange.200701732}, abstractNote={Tri-, Di- und Monoradikale: Die Reaktivität des σ,σ,σ-Triradikals 2,4,6-Tridehydropyridinium wurde mit derjenigen verwandter Mono- und Diradikale in einem Fourier-Transformations-Ionenzyklotronresonanz-Massenspektrometer verglichen. Das Triradikal hat einen Dublett-Grundzustand und geht an drei Positionen Radikalreaktionen ein. Bezüglich der Reaktivität steht es verwandten Monoradikalen näher als Diradikalen.}, number={48}, journal={Angewandte Chemie}, publisher={Wiley}, author={Jankiewicz, Bartłomiej J. and Adeuya, Anthony and Yurkovich, Michael J. and Vinueza, Nelson R. and Gardner, Samuel J. and Zhou, Meng and Nash, John J. and Kenttämaa, Hilkka I.}, year={2007}, month={Dec}, pages={9358–9361} }
 @article{jankiewicz_adeuya_yurkovich_vinueza_gardner_zhou_nash_kenttämaa_2007, title={Reactivity of an Aromatic σ,σ,σ-Triradical: The 2,4,6-Tridehydropyridinium Cation}, volume={46}, ISSN={1433-7851 1521-3773}, url={http://dx.doi.org/10.1002/anie.200701732}, DOI={10.1002/anie.200701732}, abstractNote={Tri-, bi-, and monoradicals: The reactivity of a σ,σ,σ-triradical, 2,4,6-tridehydropyridinium cation, was compared with that of related mono- and biradicals in a Fourier transform ion cyclotron resonance mass spectrometer. The triradical has a doublet ground state and contains three interacting radical sites. The reactivity of the triradical more closely resembles that of related monoradicals than related biradicals.}, number={48}, journal={Angewandte Chemie International Edition}, publisher={Wiley}, author={Jankiewicz, Bartłomiej J. and Adeuya, Anthony and Yurkovich, Michael J. and Vinueza, Nelson R. and Gardner, Samuel J. and Zhou, Meng and Nash, John J. and Kenttämaa, Hilkka I.}, year={2007}, month={Dec}, pages={9198–9201} }