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Articles 1 - 8 of 8
Full-Text Articles in Life Sciences
An International Laboratory Comparison Of Dissolved Organic Matter Composition By High Resolution Mass Spectrometry: Are We Getting The Same Answer?, Jeffrey A. Hawkes, Juliana D'Andrilli, Jeffrey N. Agar, Mark P. Barrow, Stephanie M. Berg, Núria Catalán, Hongmei Chen, Rosalie K. Chu, Richard B. Cole, Thorsten Dittmar, Rémy Gavard, Gerd Gleixner, Patrick G. Hatcher, Chen He, Nancy J. Hess, Ryan H.S. Hutchins, Amna Ijaz, Hugh E. Jones, William Kew, Maryam Khaksari, Diana Catalina Palacio Lozano, Jitao Lv, Lynn R. Mazzoleni, Beatriz E. Noriega-Ortega, Helena Osterholz, Nikola Radoman, Christina K. Remucal, Nicholas D. Schmitt, Simeon K. Schum, Quan Shi, Carsten Simon, Gabriel Singer, Rachel L. Sleighter, Aron Stubbins, Mary J. Thomas, Nikola Tolic, Shuzhen Zhang, Phoebe Zito, David C. Podgorski
An International Laboratory Comparison Of Dissolved Organic Matter Composition By High Resolution Mass Spectrometry: Are We Getting The Same Answer?, Jeffrey A. Hawkes, Juliana D'Andrilli, Jeffrey N. Agar, Mark P. Barrow, Stephanie M. Berg, Núria Catalán, Hongmei Chen, Rosalie K. Chu, Richard B. Cole, Thorsten Dittmar, Rémy Gavard, Gerd Gleixner, Patrick G. Hatcher, Chen He, Nancy J. Hess, Ryan H.S. Hutchins, Amna Ijaz, Hugh E. Jones, William Kew, Maryam Khaksari, Diana Catalina Palacio Lozano, Jitao Lv, Lynn R. Mazzoleni, Beatriz E. Noriega-Ortega, Helena Osterholz, Nikola Radoman, Christina K. Remucal, Nicholas D. Schmitt, Simeon K. Schum, Quan Shi, Carsten Simon, Gabriel Singer, Rachel L. Sleighter, Aron Stubbins, Mary J. Thomas, Nikola Tolic, Shuzhen Zhang, Phoebe Zito, David C. Podgorski
Chemistry & Biochemistry Faculty Publications
High-resolution mass spectrometry (HRMS) has become a vital tool for dissolved organic matter (DOM) characterization. The upward trend in HRMS analysis of DOM presents challenges in data comparison and interpretation among laboratories operating instruments with differing performance and user operating conditions. It is therefore essential that the community establishes metric ranges and compositional trends for data comparison with reference samples so that data can be robustly compared among research groups. To this end, four identically prepared DOM samples were each measured by 16 laboratories, using 17 commercially purchased instruments, using positive-ion and negative-ion mode electrospray ionization (ESI) HRMS analyses. The …
Comparison Of A Simplified Cupric Oxide Oxidation Hplc Method With The Traditional Gc-Ms Method For Characterization Of Lignin Phenolics In Environmental Samples (Vol 13, Pg 1, 2015), Luni Sun, Robert G. M. Spencer, Peter J. Hernes, Rachael Y. Dyda, Kenneth Mopper
Comparison Of A Simplified Cupric Oxide Oxidation Hplc Method With The Traditional Gc-Ms Method For Characterization Of Lignin Phenolics In Environmental Samples (Vol 13, Pg 1, 2015), Luni Sun, Robert G. M. Spencer, Peter J. Hernes, Rachael Y. Dyda, Kenneth Mopper
Chemistry & Biochemistry Faculty Publications
In our article entitled “Comparison of a simplified cupric oxide oxidation HPLC method with the traditional GC-MS method for characterization of lignin phenolics in environmental samples” (Limnol. Oceanogr.: Methods 13, 2015, 1–52), doi: 10.1002/lom3.10001, we would like to correct the errors in Fig. 2 and Table 2 as mentioned below. The label to Fig. 2(a) needs to be transposed as indicated in the corrected Fig. 2 image below.
Studies On Hydroxyl Radical Formation And Correlated Photoflocculation Process Using Degraded Wood Leachate As A Cdom Source, Luni Sun, Kenneth Mopper
Studies On Hydroxyl Radical Formation And Correlated Photoflocculation Process Using Degraded Wood Leachate As A Cdom Source, Luni Sun, Kenneth Mopper
Chemistry & Biochemistry Faculty Publications
In this study, we examined hydroxyl radical (•OH) formation with respect to photoreactivity of colored dissolved organic matter (CDOM), the Fenton reaction, and photoflocculation using leachate from decaying wood. The relationship between •OH photoproduction rate and leachate optical properties (UV-visible absorption and fluorescence excitation-emission matrices (EEMS)) was studied during irradiation using a UV solar simulator. The results showed that the •OH photochemical formation rate is strongly related to humic-like fluorescence as characterized by parallel factor analysis (PARAFAC), and that these fluorescence components are more photolabile than most of the other CDOM components. Fourier transform infrared spectroscopy (FT-IR) indicated the photodegradation …
A Preliminary Examination Of An In Situ Dual Dye Approach To Measuring Light Fluxes In Lotic Systems, Elizabeth C. Minor, Elizabeth James, Jay A. Austin, Veronica Nelson, Ryan Lusk, Kenneth Mopper
A Preliminary Examination Of An In Situ Dual Dye Approach To Measuring Light Fluxes In Lotic Systems, Elizabeth C. Minor, Elizabeth James, Jay A. Austin, Veronica Nelson, Ryan Lusk, Kenneth Mopper
Chemistry & Biochemistry Faculty Publications
Light is a critical parameter in aquatic ecosystems, affecting primary production and in situ photochemistry. However, measuring light exposure for suspended particles or dissolved components in a dynamic water column can be challenging with existing Eulerian approaches. Here, we assess the simultaneous deployment of two dyes differing in photolability (rhodamine WT and fluorescein) as a Lagrangian measure of sunlight exposure in a lotic system. Fluorescein is sensitive to light exposure; rhodamine WT is relatively photostable. We examined dye fluorescence at various pH, salinity, and temperature conditions. We also tested dye photolability as a function of pH and wavelength range. In …
Characterization Of Heterogeneities And Domains In Aquatic And Sedimentary Organic Matter By 1 H Spin Diffusion: Potential For Elucidating The Formation Mechanisms, Jingdong Mao, Xiaoyan Cao
Characterization Of Heterogeneities And Domains In Aquatic And Sedimentary Organic Matter By 1 H Spin Diffusion: Potential For Elucidating The Formation Mechanisms, Jingdong Mao, Xiaoyan Cao
Chemistry & Biochemistry Faculty Publications
Although the information on domains and heterogeneities of natural organic matter (NOM) can provide insights into its formation mechanisms, the appropriate solid-state NMR technique for measuring them is still lacking. The traditional technique requires mobility differences in NOM whereas NOM components are primarily rigid. We introduced a new 1H spin diffusion technique, 1H-13C two-dimensional heteronuclear correlation (2D HETCOR) NMR with 1H spin diffusion, for characterization of domains and heterogeneities in aquatic and sedimentary organic matter. It was achieved by collecting a series of 2D HETCOR spectra with a variable mixing time, tm', and …
Absorption Spectral Slopes And Slope Ratios As Indicators Of Molecular Weight, Source, And Photobleaching Of Chromophoric Dissolved Organic Matter, John R. Helms, Aron Stubbins, Jason D. Ritchie, Elizabeth C. Minor, David J. Kieber, Kenneth Mopper
Absorption Spectral Slopes And Slope Ratios As Indicators Of Molecular Weight, Source, And Photobleaching Of Chromophoric Dissolved Organic Matter, John R. Helms, Aron Stubbins, Jason D. Ritchie, Elizabeth C. Minor, David J. Kieber, Kenneth Mopper
Chemistry & Biochemistry Faculty Publications
A new approach for parameterizing dissolved organic matter ( DOM) ultraviolet-visible absorption spectra is presented. Two distinct spectral slope regions ( 275-295 nm and 350-400 nm) within log-transformed absorption spectra were used to compare DOM from contrasting water types, ranging from wetlands (Great Dismal Swamp and Suwannee River) to photobleached oceanic water ( Atlantic Ocean). On the basis of DOM size-fractionation studies ( ultrafiltration and gel filtration chromatography), the slope of the 275-295- nm region and the ratio of these slopes (SR; 275-295- nm slope : 350-400- nm slope) were related to DOM molecular weight ( MW) and …
Naturally Present Fatty Acids As Internal Calibrants For Fourier Transform Mass Spectra Of Dissolved Organic Matter, Rachel L. Sleighter, Georgina A. Mckee, Zhanfei Liu, Patrick G. Hatcher
Naturally Present Fatty Acids As Internal Calibrants For Fourier Transform Mass Spectra Of Dissolved Organic Matter, Rachel L. Sleighter, Georgina A. Mckee, Zhanfei Liu, Patrick G. Hatcher
Chemistry & Biochemistry Faculty Publications
The analysis of dissolved organic matter ( DOM) by Fourier transform ion cyclotron resonance mass spectrometry ( FTICR- MS) has gained wide interest recently, driven primarily by its ultrahigh resolving power and mass accuracy. Accurate calibration of mass spectra is a key step to successfully decipher the DOM components. We propose a simple and accurate method to internally calibrate the peaks in the complex spectra without the need to add a calibrant. Mass spectra of DOM samples from the Dismal Swamp, Virginia, and the lower Chesapeake Bay display the presence of naturally occurring fatty acids which can be readily recognized …
Effects Of Salinity Changes On The Photodegradation And Ultraviolet-Visible Absorbance Of Terrestrial Dissolved Organic Matter, E. C. Minor, J. Pothen, B. J. Dalzell, H. Abdulla, K. Mopper
Effects Of Salinity Changes On The Photodegradation And Ultraviolet-Visible Absorbance Of Terrestrial Dissolved Organic Matter, E. C. Minor, J. Pothen, B. J. Dalzell, H. Abdulla, K. Mopper
Chemistry & Biochemistry Faculty Publications
We performed laboratory studies to determine the effects of salinity on the photodegradation of dissolved organic matter (DOM) from the Great Dismal Swamp, Virginia, an important source of terrestrial DOM to the lower Chesapeake Bay. Samples were created by mixing Great Dismal Swamp water (ionic strength approximate to 0 mol L-1) with modified artificial seawater solutions of differing salinities while keeping the final dissolved organic carbon (DOC) concentration constant. These samples were then irradiated for 24 h in a light box providing ultraviolet (UV) light similar to that of natural sunlight. Light absorbance and DOC concentrations decreased after …