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Title: 4-Methoxypyridine-(pyridine-2,6-dicarboxylato-N,O,O′) copper(II).
Creator: McManus, Gregory, Perry, John J., Zaworotko, Michael J.
Abstract / Description: The synthesis and X-ray crystal structure of [Cu(C7H3NO4)(C6H7NO)], [Cu(dipic)(4-MeO-Py)], (dipic = pyridine-2,6-dicarboxylate, 4-MeO-Py = 4-methoxypyridine), is described. Molecules of [Cu(dipic)(4-MeO-Py)] are formed {via} coordination of the copper(II) cation to two nitrogen atoms, from the dipic and 4-MeO-Py ligands respectively, and to two oxygen atoms from the carboxylate groups of the dipic ligand. The molecules pack in a non-centrosymmetric manner, stacked eclipsed with respect to one...
Show moreThe synthesis and X-ray crystal structure of [Cu(C7H3NO4)(C6H7NO)], [Cu(dipic)(4-MeO-Py)], (dipic = pyridine-2,6-dicarboxylate, 4-MeO-Py = 4-methoxypyridine), is described. Molecules of [Cu(dipic)(4-MeO-Py)] are formed {via} coordination of the copper(II) cation to two nitrogen atoms, from the dipic and 4-MeO-Py ligands respectively, and to two oxygen atoms from the carboxylate groups of the dipic ligand. The molecules pack in a non-centrosymmetric manner, stacked eclipsed with respect to one another along the b-axis and aligned parallel in a head-to-tail motif. The title compound crystallizes in the orthorhombic space group, Pca2(1), with a = 27.339(3) Å, b = 3.7130(4) Å, c = 11.6859(12) Å, V = 1186.2(2) Å3, and Z = 4. The structure was solved by direct methods and refined by least-squares methods to a final R-factor of 0.0327 for 2648 independent reflections.
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Date Issued: 2004-12-01
Identifier: fgcu_ir_000516
Format: Citation

Title: A Case Study for Teaching Quantitative Biochemical Buffer Problems Using Group Work and "Khan Style" Videos .
Creator: Reilly, John, Dubetz, Terry A., Davis-McGibony, C. Michele, Ramoutar, Ria, Rudd, Gillian, Brown, David, Frost, Laura, Coticone, Sulekha, Beharry, Zanna, Barreto, Jose
Abstract / Description: New technological developments have minimized training, hardware expense, and distribution problems for the production and use of instructional videos, and any science instructor can now make instructional videos for their classes. We created short "Khan style" videos for the topic of buffers in biochemistry and assigned them as homework, followed by group problem-solving sessions in class. We tested the hypothesis that "inverting the classroom" (a popular terminology for the new format)...
Show moreNew technological developments have minimized training, hardware expense, and distribution problems for the production and use of instructional videos, and any science instructor can now make instructional videos for their classes. We created short "Khan style" videos for the topic of buffers in biochemistry and assigned them as homework, followed by group problem-solving sessions in class. We tested the hypothesis that "inverting the classroom" (a popular terminology for the new format) could replace traditional live lectures, which are typically followed by assigning homework problems (traditionally, mostly solved by students working alone). Using the inverted classroom method, we found that most of our students achieved mastery in solving buffer problems on an exam, without any live lecture (the class averages were ~80%). Our survey data showed that both students and faculty reviewers considered the new format to be an effective teaching tool. To validate our results, we included six survey questions concerning rigor and fairness; positive data were obtained in this regard, with a mean of ~4, on a 5-point scale. We included three separate classes in our study with grade data from 67 students and survey data from 42 students.
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Date Issued: 2014-09-01
Identifier: fgcu_ir_000551
Format: Citation

Title: A co-crystal of 1,10-phenanthroline with boric acid: a novel aza-aromatic complex.
Creator: Mirjafari, Arsalan, Pham, Lam, Smith, Philip J., Sykora, Richard E., Davis, James H.
Abstract / Description: The title compound, C12H8N2·2B(OH)3, is best described as a host-guest complex in which the B(OH)3 mol-ecules form a hydrogen-bonded cyclic network of layers parallel to the ab plane into which the 1,10-phenanthroline mol-ecules are bound. An extensive network of hydrogen bonds are responsible for the crystal stability. No π-stacking inter-actions occur between the 1,10-phenanthroline mol-ecules.
Date Issued: 2013-07-15
Identifier: 10.1107/S1600536813015134, fgcu_ir_000067, http://scripts.iucr.org/cgi-bin/paper?S1600536813015134
Format: Citation

Title: A co-crystal of 1,10-phenanthroline with boric acid: a novel aza-aromatic complex.
Creator: Mirjafari, Arsalan, Pham, Lam, Smith, Philip J., Sykora, Richard E., Davis, James H.
Abstract / Description: The title compound, C12H8N2·2B(OH)3, is best described as a host-guest complex in which the B(OH)3 molecules form a hydrogen-bonded cyclic network of layers parallel to the ab plane into which the 1,10-phenanthroline molecules are bound. An extensive network of hydrogen bonds are responsible for the crystal stability. No [pi]-stacking interactions occur between the 1,10-phenanthroline molecules.
Date Issued: 2013-05-31
Identifier: fgcu_ir_000535
Format: Document (PDF)

Title: A Comprehensive Search for Gamma-Ray Lines in the First Year of Data from the INTEGRAL Spectrometer.
Creator: Watanabe, Kenji, Teegarden, B.J.
Abstract / Description: We have carried out an extensive search for gamma-ray lines in the first year of public data from the spectrometer (SPI) on the INTEGRAL mission. INTEGRAL has spent a large fraction of its observing time in the Galactic plane with particular concentration in the Galactic center (GC) region (~3 Ms in the first year). Hence the most sensitive search regions are in the Galactic plane and center. The phase space of the search spans the energy range 20-8000 keV and line widths from 0 to 1000 keV ...
Show moreWe have carried out an extensive search for gamma-ray lines in the first year of public data from the spectrometer (SPI) on the INTEGRAL mission. INTEGRAL has spent a large fraction of its observing time in the Galactic plane with particular concentration in the Galactic center (GC) region (~3 Ms in the first year). Hence the most sensitive search regions are in the Galactic plane and center. The phase space of the search spans the energy range 20-8000 keV and line widths from 0 to 1000 keV (FWHM). It includes both diffuse and pointlike emission. We have searched for variable emission on timescales down to ~1000 s. Diffuse emission has been searched for on a range of different spatial scales from ~20° (the approximate field of view of the spectrometer) up to the entire Galactic plane. Our search procedures were verified by the recovery of the known gamma-ray lines at 511 and 1809 keV at the appropriate intensities and significances. We find no evidence for any previously unknown gamma-ray lines. The upper limits range from a few × 10-5 to a few × 10-2 cm-2 s-1 depending on line width, energy, and exposure; regions of strong instrumental background lines were excluded from the search. Comparison is made between our results and various prior predictions of astrophysical lines.
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Date Issued: 2006-03-22
Identifier: fgcu_ir_000558
Format: Citation

Title: A Mechanistic Study on the Catalytic, Asymmetric α‐Bromination of Acid Chlorides.
Creator: Paull, Daniel, Dogo-Isonagie, Cajetan, Bekele, Tefsit, France, Stefan, Wolfer, Jamison, Weatherwax, Anthony, Dudding, Travis, Lectka, Thomas
Abstract / Description: The mechanism of the catalytic, asymmetric α‐bromination of acid chlorides is probed through a series of crossover experiments, ion‐pairing tests, and kinetic resolution studies to shed light on the factors that contribute to, and limit the production of, optically‐active α‐bromo esters. In order to understand better the observed sense of induction, as well as the high degree of enantiomeric excess exhibited by these products, extensive molecular modeling is employed on the relevant...
Show moreThe mechanism of the catalytic, asymmetric α‐bromination of acid chlorides is probed through a series of crossover experiments, ion‐pairing tests, and kinetic resolution studies to shed light on the factors that contribute to, and limit the production of, optically‐active α‐bromo esters. In order to understand better the observed sense of induction, as well as the high degree of enantiomeric excess exhibited by these products, extensive molecular modeling is employed on the relevant transition states. Finally, the usefulness of the α‐bromo ester products is demonstrated by their simple derivatization into chiral epoxides.
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Date Issued: 2007-02-13
Identifier: fgcu_ir_000547
Format: Citation

Title: A new 65.8 topology and a distorted 65.8 CdSO4 topology: two new supramolecular isomers of [M2(bdc)2(L)2]n coordination polymers.
Creator: McManus, Gregory, Moulton, Brian, Abourahma, Heba, Bradner, Michael W., Lu, Jiangiang, Zaworotko, Michael J.
Abstract / Description: We report the crystal structures of two new coordination polymers that have similar composition but, despite having the same circuit symbol and Schläfli notation, different topologies: a novel 3D topology (USF-1) and a CdSO4-like topology.
Date Issued: 2003-05-16
Identifier: fgcu_ir_000521
Format: Citation

Title: A novel metal–organic ternary topology constructed from triangular, square and tetrahedral molecular building blocks.
Creator: McManus, Gregory, Wang, Zhenqiang, Beauchamp, Derek A., Zaworotko, Michael J.
Abstract / Description: A novel metal–organic network [Cu4(5-NH2-1,3-bdc)4(pyridine)2(H2O)2]n, displaying an unprecedented topology has been constructed utilizing the different coordinating functional groups of 5-NH2-1,3-bdc to generate a ternary network based upon vertex-linked triangular, square and tetrahedral molecular building blocks (MBBs).
Date Issued: 2007-10-16
Identifier: fgcu_ir_000511
Format: Citation

Title: A photoacoustic calorimetric characterization of the reaction enthalpy and volume for the preparation of a reactive intermediate from CpMn(CO)3.
Creator: Davies, Kevin, Maivald, David, Grabowski, Joseph J.
Abstract / Description: Photoacoustic calorimetry (PAC) allows measurement of the energetics of reactive intermediates. Here, we report the examination of the metal carbonyl η5-CpMn(CO)3 (Cp, cyclopentadiene) via time-independent PAC, in a homologous series of solvents. The measured heat releases allow one to determine simultaneously the enthalpy and volume change resulting from the photodissociation of CpMn(CO)3. While the photoacoustic signal results from both of these processes, it has often been assumed that the...
Show morePhotoacoustic calorimetry (PAC) allows measurement of the energetics of reactive intermediates. Here, we report the examination of the metal carbonyl η5-CpMn(CO)3 (Cp, cyclopentadiene) via time-independent PAC, in a homologous series of solvents. The measured heat releases allow one to determine simultaneously the enthalpy and volume change resulting from the photodissociation of CpMn(CO)3. While the photoacoustic signal results from both of these processes, it has often been assumed that the volume change contribution to the observed photoacoustic signal is negligible for small molecules undergoing photodissociation. The current study tests the assumption of a negligible reaction volume by using a more complete treatment. The reaction of an equimolar number of photons and CpMn(CO)3 molecules, the subsequent photodissociation of the Mn–CO bond, and the ligation of a solvent molecule in an alkane solvent yields ΔHobs = 32.7 ± 0.7 kcal/mol and ΔVchem = 11.0 ± 1.3 mL/mol, both of which are independent of the quantum yield of photodissociation. A detailed analysis of the quantum yield is included (using both previously reported measurements, and new data from this work), from which we determine Φdiss = 0.635. This quantum yield allows us to determine ΔHrxn = 51.6 kcal/mol and ΔVrxn = 17.3 mL/mol. These results demonstrate that if the contribution of the reaction volume change to the photoacoustic signal is ignored, the reaction enthalpy derived would underestimate the true value by 7%. We also estimate the BDE{Cp(CO)2Mn–CO} to be 59.4 kcal/mol.
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Date Issued: 2008-06-01
Identifier: fgcu_ir_000496
Format: Citation

Title: A regioselective etherification of pyridoxine via an ortho-pyridinone methide intermediate.
Creator: Boyce, Greg, Yazarians, Jessica A., Jiménez, Brian L.
Abstract / Description: The catalyst-free, regioselective synthesis of 4′-O-substituted pyridoxine derivatives under solventless conditions is described. The methodology relies on the highly regioselective formation of the ortho-pyridinone methide from pyridoxine and subsequent oxa-Michael addition of alcohol nucleophiles. This methodology provides good to excellent yields for primary and secondary alcohols and moderate yields for tertiary alcohols.
Date Issued: 2017-06-01
Identifier: fgcu_ir_000484
Format: Citation

Title: A Shape Model of the Taxonomic A-Class Asteroids 446 Aeternitas .
Creator: Fauerbach, Michael, Lucas, Michael P., Ryan, Jeffrey G.
Abstract / Description: We acquired dense rotational lightcurves for the taxonomic A-class asteroid 446 Aeternitas during three apparitions in 2006, 2007-2008, and 2009. Our results show that 446 Aeternitas is a prograde rotator, has a distinct angular shape, and is moderately elongated. Several planar areas in the convex shape model suggest concavities, possibly large craters or saddles. These features suggest that 446 Aeternitas is likely to be a collisional fragment. We found a pole solution of ? = +52o, ? = 356o...
Show moreWe acquired dense rotational lightcurves for the taxonomic A-class asteroid 446 Aeternitas during three apparitions in 2006, 2007-2008, and 2009. Our results show that 446 Aeternitas is a prograde rotator, has a distinct angular shape, and is moderately elongated. Several planar areas in the convex shape model suggest concavities, possibly large craters or saddles. These features suggest that 446 Aeternitas is likely to be a collisional fragment. We found a pole solution of ? = +52o, ? = 356o with no mirror solution apparent. However, low chi-square pole solutions centered on ecliptic longitude ? = 210o cannot be ruled out, leaving the ecliptic longitude of 446 Aeternitas unconstrained. Lightcurves measured over three asteroid apparitions were used during the inversion process to determine a refined rotational period of 15.73743 ± 0.00005 h. Typical errors for ecliptic latitude and longitude values are ± 10 degrees.
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Date Issued: 2012-07-01
Identifier: fgcu_ir_000501
Format: Citation

Title: A Simple Spectrophotometric Determination of an Equilibrium Constant That Does Not Require Any Measurementsof pH, Mass, Volume, Concentration, or Molar Absorptivity: The pKaof Methyl Red.
Creator: Brown, David, Dubetz, Terry, Barreto, Patricia D., Barreto, Jose
Abstract / Description: This laboratory exercise is intended for first-year chemistry students. It is designed to determine the pKa of Methyl Red with good precision and accuracy, while eliminating the need for pH meters, balances, pipets, or multiple buffer solutions. The experimental design is intended to encourage data sharing in class, requires only simple and rapid calculations, and will generate some thought provoking results about the relationship between pH and pKa.
Date Issued: 2007-09-14
Identifier: fgcu_ir_000492
Format: Citation

Title: A spectrophotometric determination of the energy of activation (Ea) for a complexation reaction: The kinetics of formation of Cr(III)/EDTA.
Creator: Brown, David, Dubetz, Terry, Alberte, Randall, Barreto, Jose, Kakareka, Joseph
Abstract / Description: For a first-order reaction, the integrated rate expression is ln [Rt]/[Ro] = –kt, where [Ro] and [Rt] represent reactant concentrations at time zero and any time, t, respectively. The formation of a purple complex by Cr(III) and EDTA closely adheres to first-order kinetics and, as the purple complex forms, the absorbance is easily measured over time. To study this reaction, we defined At as the product absorbance at any time, and Af as the final product absorbance. By experimentally...
Show moreFor a first-order reaction, the integrated rate expression is ln [Rt]/[Ro] = –kt, where [Ro] and [Rt] represent reactant concentrations at time zero and any time, t, respectively. The formation of a purple complex by Cr(III) and EDTA closely adheres to first-order kinetics and, as the purple complex forms, the absorbance is easily measured over time. To study this reaction, we defined At as the product absorbance at any time, and Af as the final product absorbance. By experimentally determining Af in advance and measuring At at any time during the reaction, the ratio At /Af reveals the extent of the reaction. The rate constant, k, can ultimately be determined from At /Af at various temperatures with a hand calculator. The thermodynamic parameter, Ea, and the kinetic parameter, A, are then obtained from an Arrhenius plot of ln k versus 1/T. The complexation of Cr(III) by EDTA has several important advantages in this thermodynamic and kinetic study. The stoichiometry between reactants and products is 1:1, the reaction can be driven to completion and is irreversible, the final product has a stable color, and the reactants are almost colorless using the concentrations described. The reaction has a marked temperature dependence that allows students to observe the effect of temperature on the rate constant. An introduction to Ea and A in the second semester of general chemistry is very important because it provides a foundation for later discussions of catalysis.
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Date Issued: 2005-05-23
Identifier: fgcu_ir_000493
Format: Citation

Title: A Surprising Mechanistic “Switch” in Lewis Acid Activation: A Bifunctional, Asymmetric Approach to α-Hydroxy Acid Derivatives.
Creator: Paull, Daniel, Abraham, Ciby J., Bekele, Tefsit, Scerba, Michael T., Dudding, Travis, Lectka, Thomas
Abstract / Description: We report a detailed synthetic and mechanistic study of an unusual bifunctional, sequential hetero-Diels−Alder/ring-opening reaction in which chiral, metal complexed ketene enolates react with o-quinones to afford highly enantioenriched, α-hydroxylated carbonyl derivatives in excellent yield. A number of Lewis acids were screened in tandem with cinchona alkaloid derivatives; surprisingly, trans-(Ph3P)2PdCl2 was found to afford the most dramatic increase in yield and rate of reaction. A series...
Show moreWe report a detailed synthetic and mechanistic study of an unusual bifunctional, sequential hetero-Diels−Alder/ring-opening reaction in which chiral, metal complexed ketene enolates react with o-quinones to afford highly enantioenriched, α-hydroxylated carbonyl derivatives in excellent yield. A number of Lewis acids were screened in tandem with cinchona alkaloid derivatives; surprisingly, trans-(Ph3P)2PdCl2 was found to afford the most dramatic increase in yield and rate of reaction. A series of Lewis acid binding motifs were explored through molecular modeling, as well as IR, UV, and NMR spectroscopy. Our observations document a fundamental mechanistic “switch”, namely the formation of a tandem Lewis base/Lewis acid activated metal enolate in preference to a metal-coordinated quinone species (as observed in other reactions of o-quinone derivatives). This new method was applied to the syntheses of several pharmaceutical targets, each of which was obtained in high yield and enantioselectivity.
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Date Issued: 2008-11-17
Identifier: fgcu_ir_000543
Format: Citation

Title: A Writing and Ethics Component for a Quantum Mechanics, Physical Chemistry Course.
Creator: Reilly, John, Strickland, Michael
Abstract / Description: A writing-across-the-curriculum and ethics component is presented for a second-semester, physical chemistry course. The activity involves introducing ethical issues pertinent to scientists. Students are asked to read additional material, participate in discussions, and write essays and a paper on an ethical issue. The writing and discussion component provides another opportunity for students to read and think about broader ethical issues in the scientific community. Two items were found to...
Show moreA writing-across-the-curriculum and ethics component is presented for a second-semester, physical chemistry course. The activity involves introducing ethical issues pertinent to scientists. Students are asked to read additional material, participate in discussions, and write essays and a paper on an ethical issue. The writing and discussion component provides another opportunity for students to read and think about broader ethical issues in the scientific community. Two items were found to make the writing element successful: (1) some type of student support for writing (workshop, writing center, etc.) and (2) a guest lecture from a philosophy faculty member to review ethical theories. In addition, a pre- and postforum questionnaire concerning ethical issues for scientists was given to students. Directional differences in agreement were found for such issues as limits on the pursuit of knowledge, development of weapons of mass destruction, and how well-rounded scientists should be.
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Date Issued: 2010-03-01
Identifier: fgcu_ir_000554
Format: Citation

Title: An Asymmetric Vinylogous Michael Cascade of Silyl Glyoximide, Vinyl Grignard, and Nitroalkenes via Long Range Stereoinduction.
Creator: Boyce, Greg, Johnson, Jeffrey S.
Abstract / Description: A diastereoselective auxiliary-mediated vinylation/[1,2]-Brook rearrangement/vinylogous Michael cascade of silyl glyoximide, vinylmagnesium bromide, and nitroalkenes is described. The reaction occurs with complete regio- and diastereocontrol in good yield. The diastereoselectivity is induced by a rare instance of 1,7-chirality transfer that is hypothesized to arise from a trans-multihetero-decalin transition state.
Date Issued: 2016-02-02
Identifier: fgcu_ir_000486
Format: Citation

Title: An Asymmetric, Bifunctional Catalytic Approach to Non-Natural α-Amino Acid Derivatives.
Creator: Paull, Daniel, Alden- Danforth, Ethan, Wolfer, Jamison, Dogo-Isonagie, Cajetan, Abraham, Ciby J., Lectka, Thomas
Abstract / Description: A catalytic, asymmetric process for the synthesis of 1,4-benzoxazinones from o-benzoquinone imides and ketene enolates is reported. Addition of Lewis acids (Zn(OTf)2, In(OTf)3, and in particular Sc(OTf)3) creates a bifunctional catalytic system that dramatically increases the reaction rate and the yield of these non-natural amino acid precursors while preserving the remarkable enantioselectivity inherent to the reaction. Cocatalyst Sc(OTf)3 increases the yield by up to 42% while producing...
Show moreA catalytic, asymmetric process for the synthesis of 1,4-benzoxazinones from o-benzoquinone imides and ketene enolates is reported. Addition of Lewis acids (Zn(OTf)2, In(OTf)3, and in particular Sc(OTf)3) creates a bifunctional catalytic system that dramatically increases the reaction rate and the yield of these non-natural amino acid precursors while preserving the remarkable enantioselectivity inherent to the reaction. Cocatalyst Sc(OTf)3 increases the yield by up to 42% while producing products in >99% ee.
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Date Issued: 2007-06-08
Identifier: fgcu_ir_000546
Format: Citation

Title: An Investigation of Commercially Available Batteries.
Creator: Cyr, Noah, Research Day
Abstract / Description: An inexpensive battery tester was designed and fabricated to measure the capacity of a serial of commercially available AA batteries in the laboratory. The key component was a potential auto logger. Several brands and types of batteries were investigated. Their performance in terms of energy capacity, effective energy capacity, and energy density were calculated. The results will provide guidance to common battery users and raise the awareness of environmental sustainability as well.
Date Issued: 2017
Identifier: fgcu_UGR_0008
Format: Document (PDF)

Title: Analysis of the Self-Association of Aliphatic Alcohols Using Fourier Transform Infrared (FT-IR) Spectroscopy.
Creator: Reilly, John, Thomas, Arun, Gibson, Aileen R., Luebehusen, Chi Y., Donojue, Marc D.
Abstract / Description: A number of industrially important systems contain molecules, such as alcohols, that form hydrogen bonds. To correlate the thermodynamic properties of such systems, assumptions must be made in modeling the chemical equilibrium. It has been found that the data can be fit to a high degree of accuracy if it is assumed that the system contains monomers, dimers, and trimers or tetramers. Alcohols are often modeled by an infinite equilibrium model that takes into account associated species of all...
Show moreA number of industrially important systems contain molecules, such as alcohols, that form hydrogen bonds. To correlate the thermodynamic properties of such systems, assumptions must be made in modeling the chemical equilibrium. It has been found that the data can be fit to a high degree of accuracy if it is assumed that the system contains monomers, dimers, and trimers or tetramers. Alcohols are often modeled by an infinite equilibrium model that takes into account associated species of all sizes. In this model and in others as well, an additional assumption must be made concerning the values of the various equilibrium constants; it usually is assumed that all of the equilibrium constants for a given species are equal. In this work, Fourier transform infrared (FT-IR) spectroscopy has been used to study the chemical association of aliphatic alcohols. Analysis of FT-IR spectroscopic data was used to determine the species present in a mixture and the corresponding equilibrium constants and also to evaluate the validity of the assumptions commonly made. The effects of molecular size on the enthalpic and entropic contributions to the equilibrium constant were determined by analyzing spectroscopic data for alcohols with carbon numbers of 5, 7, and 9 at different temperatures. A qualitative analysis of the spectra revealed that there are at least three types of hydrogen bonds in the mixtures. Equilibrium constants, enthalpies and entropies of association, and absorptivities of the unassociated OH stretch were determined. The equilibrium constants obtained were found to be a function of temperature and chain length.
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Date Issued: 2013-09-13
Identifier: fgcu_ir_000552
Format: Citation

Title: Analysis of Triclocarban in Aquatic Samples by Liquid Chromatography Electrospray Ionization Mass Spectrometry.
Creator: Paull, Daniel, Halden, Rolf U.
Abstract / Description: Triclocarban, N-(4-chlorophenyl)-N‘-(3,4-dichlorophenyl)urea, is a polychlorinated phenyl urea pesticide, marketed under the trademark TCC and used primarily as an antibacterial additive in personal care products. Despite its extensive use over several decades, environmental occurrence data on TCC are scarce. This is due in part to a lack of analytical techniques offering the desired sensitivity, selectivity, affordability, and ease of use. This need is addressed here by introducing a liquid...
Show moreTriclocarban, N-(4-chlorophenyl)-N‘-(3,4-dichlorophenyl)urea, is a polychlorinated phenyl urea pesticide, marketed under the trademark TCC and used primarily as an antibacterial additive in personal care products. Despite its extensive use over several decades, environmental occurrence data on TCC are scarce. This is due in part to a lack of analytical techniques offering the desired sensitivity, selectivity, affordability, and ease of use. This need is addressed here by introducing a liquid chromatography electrospray ionization mass spectrometry (LC/ESI/MS) method allowing for the determination of TCC concentrations in aquatic environments at the ng/L level. TCC was concentrated from aqueous samples by solid-phase extraction, separated from interferences on a C18 column by either isocratic or gradient elution, and detected and identified in negative ESI mode by selectively monitoring the (M − H)- base peak (m/z 313) and its 37Cl-containing isotopes (m/z 315, 317) that served as reference ions. Particulates contained in aquatic samples were extracted and analyzed separately. Accurate quantification was achieved using stable isotopes of TCC and triclosan as internal standards. Addition of 10 mM acetic acid to the mobile phase yielded acetic acid adducts ([M − H + 60]-) that were successfully exploited to boost method sensitivity and selectivity, especially when analyzing challenging environmental matrixes. Method detection limits were matrix dependent, ranging from 3 to 50 ng/L. In 36 grab samples obtained from the Greater Baltimore area, TCC was detected in river water and wastewater at concentrations of up to 5600 and 6750 ng/L, respectively. Raw and finished drinking water did not contain detectable quantities of the pesticide (<3 ng/L). In conclusion, the new LC/ESI/MS method was applied successfully to collect environmental occurrence data on TCC in U.S. water resources. Study results suggest that the bacteriostat and pesticide is a frequent but currently underreported contaminant whose environmental fate and behavior deserve further scrutiny.
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Date Issued: 2004-08-18
Identifier: fgcu_ir_000550
Format: Citation

Chemistry. (4)	+ -
Laboratories and Demonstrations (3)	+ -
Colorimetry. (2)	+ -
Equilibrium. (2)	+ -
Ionic Liquids. (2)	+ -

Ionic liquid crystals (2)	+ -
Ionic liquids (2)	+ -
Liquids crystals (2)	+ -
Mesophase (2)	+ -
Microwave (2)	+ -
Spectrophotometry. (2)	+ -
crystal structure (2)	+ -
general chemistry (2)	+ -
1-Methyl-3-H-imidazolium nitrate (1)	+ -
Alcoholysis. (1)	+ -
Amino acid ionic liquid (1)	+ -
Amino acids. (1)	+ -
Aminolysis (1)	+ -
Analytical Chemistry. (1)	+ -
Asteroids. (1)	+ -
Asymmetric (1)	+ -
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Asymmetric synthesis. (1)	+ -
Azomethine ylide (1)	+ -
Batteries (1)	+ -
Biocatalytic (1)	+ -
Biomimetic materials (1)	+ -
Biomimetic materials. (1)	+ -
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Bottled water. (1)	+ -

Scholarly Publications (84)	+ -
FGCU Faculty (32)	+ -
Student Research (1)	+ -

Entropy. (1)	+ -
Sulfate. (1)	+ -

Bromides. (1)	+ -
Enthalpy. (1)	+ -

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