Static and dynamic fluorescence spectroscopy are used to investigate the local compositional changes in binary supercritical fluids on a picosecond time scale. A fluorescent solute molecule whose emission characteristics are sensitive to solvent polarity is used to probe the composition of the local solvent environment. The systems investigated were supercritical CO2 with the addition of small amounts of the polar cosolvents, CH3OH and CH3CN. These systems exhibit a reorganization of the local solvent shell(s) about the fluorescent probe following optical excitation, a process known as solvent relaxation. Average rates for this dynamic solvation process were determined, and an Arrhenius analysis performed. It is shown that the binary supercritical fluid composed of CO2 and CH3OH can reorganize more rapidly than the CO2-CH3CN system.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLIMSport (V): pH Data Acquisition: An Inexpensive Probe and Calibration SoftwareEd Vitz and Thomas A. Betts Cite this: J. Chem. Educ. 1994, 71, 5, 412Publication Date (Print):May 1, 1994Publication History Received3 August 2009Published online1 May 1994Published inissue 1 May 1994https://doi.org/10.1021/ed071p412RIGHTS & PERMISSIONSArticle Views124Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (4 MB) Get e-Alertsclose Get e-Alerts
The Salton Sea, California, a hypersaline, closed-system lake, experiences high wind event-associated tilapia fish kills. This study reports on the occurrence of several tons of organic spheres taphonomically associated with disarticulated tilapia skeletal parts occurring along the Salton Sea's shorelines. Chemical analyses demonstrate that sphere composition is consistent with soft tissue degradation of tilapia by anaerobic bacteria producing adipocere. Infrared spectroscopy (IR) and gas chromatography (GC) reveal the presence of both triglycerides and salts of free fatty acids. Specifically, GC-MS FAME (fatty acid methyl ester) analysis identified the presence of relatively high concentrations of palmitic, oleic, stearic, pentadecanoic, and myristic acids in the adipocere spheres which are nearly identical to the fatty acid profile of Salton Sea tilapia. SEM studies document the incorporation of fragmented fish bones and detrital grains within the spheres. Formation of adipocere masses in the Salton Sea affects the buoyancy and hydrodynamic equivalence of fish bone fragments, thereby influencing deposition of disarticulated bone materials, and may affect local redox conditions at the burial site.
Frequency-domain fluorescence spectroscopy is used to study the transient solvation of 4-amino-N-methylphthalimide (4AMP) in binary supercritical fluids composed of 2-propanol and CO 2 . The time-resolved emission spectra are constructed for this system with the use of the wavelength-dependent frequency-domain data. Analysis of the experimental data indicates that: (1) 4AMP is pre-associated with 2-propanol prior to excitation; (2) the 2-propanol-induced spectral relaxation occurs on a nanosecond time scale; and (3) the excited-state reaction between 4AMP and 2-propanol is reversible.
Abstract The spotted lanternfly, Lycorma delicatula, is an introduced plant hopper that causes significant damage to host plants in the United States. Because of its affinity for tree of heaven, Ailanthus altissima, control efforts have focused on the use of the systemic insecticide, dinotefuran, in designated trap trees. There is concern about exposure to this pesticide by non-target species, especially honey bees, Apis mellifera, via lanternfly honeydew. Therefore, honey bee colonies were established in areas of high densities of trap trees and samples of honey, bees, and beeswax were collected in May, July, and October of 2017 for analysis. Samples were extracted by the QuEChERS method and analyzed using high-performance liquid chromatography with tandem mass spectrometry to determine the presence and quantity of dinotefuran. Additionally, honeydew from lanternflies was analyzed for dinotefuran and informal observations of trap tree visitors were made. None of the worker bee, wax, or honey samples indicated detectable levels of dinotefuran; however, honeydew samples collected did contain dinotefuran above the detection limit with amounts ranging from 3 to 100 ng per sample. The lack of dinotefuran in honey bee products matches the general absence of honey bees at trap trees in informal observations.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFluorescence Polarization as a Tool to Pinpoint Vesicle Thermal Phase TransitionsGary A. Baker , Thomas A. Betts , and Siddharth Pandey View Author Information Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260 Department of Physical Sciences, Kutztown University of Pennsylvania, Kutztown, PA 19530 Department of Chemistry, New Mexico Institute of Mining and Technology, Socorro, NM 87801Cite this: J. Chem. Educ. 2001, 78, 8, 1100Publication Date (Web):August 1, 2001Publication History Received3 August 2009Published online1 August 2001Published inissue 1 August 2001https://pubs.acs.org/doi/10.1021/ed078p1100https://doi.org/10.1021/ed078p1100research-articleACS PublicationsRequest reuse permissionsArticle Views983Altmetric-Citations3LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Fluorescence,Phase transitions,Polarization,Students,Vesicles Get e-Alerts
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInvestigation of Imposter Perfumes Using GC–MSKelley A. Mowery , Daniel E. Blanchard , Stephanie Smith , and Thomas A. Betts View Author Information Department of Physical Sciences, Kutztown University of PA, Kutztown, PA 19530Cite this: J. Chem. Educ. 2004, 81, 1, 87Publication Date (Web):January 1, 2004Publication History Received3 August 2009Published online1 January 2004Published inissue 1 January 2004https://pubs.acs.org/doi/10.1021/ed081p87https://doi.org/10.1021/ed081p87research-articleACS PublicationsRequest reuse permissionsArticle Views3089Altmetric-Citations11LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Molecular structure,Physical chemistry,Sample preparation,Software,Students Get e-Alerts
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCyclodextrin Inclusion Complexes with a Solvatochromic Fluorescent ProbeGary A. Baker , Nicole J. Crane , Rudolph C. Mayrhofer , and Thomas A. Betts View Author Information Department of Chemistry, State University of New York, Buffalo, NY 14260 Department of Physical Sciences, Kutztown University of PA, Kutztown, PA 19530Cite this: J. Chem. Educ. 2002, 79, 10, 1261Publication Date (Web):October 1, 2002Publication History Received3 August 2009Published online1 October 2002Published inissue 1 October 2002https://pubs.acs.org/doi/10.1021/ed079p1261https://doi.org/10.1021/ed079p1261research-articleACS PublicationsRequest reuse permissionsArticle Views1147Altmetric-Citations27LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Analytical apparatus,Fluorescence,Macrocyclic compounds,Mathematical methods,Oligosaccharides Get e-Alerts
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSteady-state and time-resolved fluorescence investigations of pyrene excimer formation in supercritical CO2JoAnn Zagrobelny, Thomas A. Betts, and Frank V. BrightCite this: J. Am. Chem. Soc. 1992, 114, 13, 5249–5257Publication Date (Print):June 1, 1992Publication History Published online1 May 2002Published inissue 1 June 1992https://pubs.acs.org/doi/10.1021/ja00039a042https://doi.org/10.1021/ja00039a042research-articleACS PublicationsRequest reuse permissionsArticle Views476Altmetric-Citations77LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpectroscopic determination of solute-fluid cluster size in supercritical nitrogen oxide (N2O)Thomas A. Betts, JoAnn Zagrobelny, and Frank V. BrightCite this: J. Am. Chem. Soc. 1992, 114, 21, 8163–8171Publication Date (Print):October 1, 1992Publication History Published online1 May 2002Published inissue 1 October 1992https://pubs.acs.org/doi/10.1021/ja00047a027https://doi.org/10.1021/ja00047a027research-articleACS PublicationsRequest reuse permissionsArticle Views145Altmetric-Citations71LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
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