An analytical method was developed for the trace analysis of a wide range of semivolatile organic compounds (SOCs) in 50-L high-elevation snow and lake water samples. The method was validated for 75 ...SOCs from seven different chemical classes (polycyclic aromatic hydrocarbons, organochlorine pesticides, amides, triazines, polychlorinated biphenyls, thiocarbamates, and phosphorothioates) that covered a wide range of physical-chemical properties including 7 orders of magnitude of octanol-water partition coefficient (log Kow = 1.4-8.3). The SOCs were extracted using a hydrophobically and hydrophilically modified divinylbenzene solid-phase extraction device (modified Speedisk). The average analyte recovery from 50 L of reverse osmosis water, using the modified Speedisk, was 99% with an average relative standard deviation of 4.8%. Snow samples were collected from the field, melted, and extracted using the modified Speedisk and a poly(tetrafluoroethylene) remote sample adapter in the laboratory. Lake water was sampled, filtered, and extracted in situ using an Infiltrex 100 fitted with a 1-m glass fiber filter to trap particulate matter and the modified Speedisk to trap dissolved SOCs. The extracts were analyzed by gas chromatographic mass spectrometry with electron impact ionization and electron capture negative ionization using isotope dilution and selective ion monitoring. Estimated method detection limits for snow and lake water ranged from 0.2 to 125 pg/L and 0.5-400 pg/L, respectively. U.S. historic and current-use pesticides were identified and quantified in snow and lake water samples collected from Rocky Mountain National Park, CO. The application of the analytical method to the analysis of SOCs in large-volume groundwater samples is also shown. PUBLICATION ABSTRACT
SOCs volatility and persistence properties cause many SOCs to become ubiquitous in the environment as well as accumulate in areas with lower temperatures such as polar or orographic regions. Many ...anthropogenic SOCs pose a serious risk to human and ecosystem health because of their persistent, bioaccumulative, and toxic properties in the environment. Unique and sensitive ecosystems exist in polar or orographic regions.Vast improvements in our understanding of the fate and transport of many SOCs have been made with research in polar or orographic regions located in eastern North America, Europe, and parts of the arctic and Antarctica. Advancements in our understanding of the fate and transport of SOCs in western U.S are hindered by the limited number and scope of past studies, sampling strategies, and current methodologies. Described herein, the development, validation, and as well as the demonstration of a new analytical method capable of measuring 75 SOCs including current and historic-use pesticides, polycyclic aromatic hydrocarbons, polychlorinated biphenyls in large-volume lake water and snowmelt samples. A novel solid phase extraction device containing hydrophilic and hydrophobic called a “modified Speedisk” was developed to handle large volume aqueous samples (50L), capture a wide range of SOCs, and capable of interfacing with an in situ submersible pump. In addition, this dissertation contains the development, validation, and demonstration of an analytical method capable of quantifying 98 SOCs including polybrominated diphenyl ethers from remote lake systems. Sediment core, snow, and lake water samples were collected, extracted, and quantified for SOCs using the methods above from fourteen high-altitude and/or high-latitude remote lake systems in western National Parks (NPs). Many SOCs demonstrated a significant regression between surficial sediment fluxes and snow fluxes (p<0.05). These significant regressions stress the importance of winter time SOC deposition in western NPs. SOC deposition in Rocky Mountain NP and Glacier NP is dependent on regional upslope wind directions and the location of regional sources (relative to the Continental Divide). Lake water concentrations and sediment fluxes were generally lower in the Alaska’s NPs and Olympic NP, due to proximity to source regions and the prevailing westerly winds.
SOCs volatility and persistence properties cause many SOCs to become ubiquitous in the environment as well as accumulate in areas with lower temperatures such as polar or orographic regions. Many ...anthropogenic SOCs pose a serious risk to human and ecosystem health because of their persistent, bioaccumulative, and toxic properties in the environment. Unique and sensitive ecosystems exist in polar or orographic regions. Vast improvements in our understanding of the fate and transport of many SOCs have been made with research in polar or orographic regions located in eastern North America, Europe, and parts of the arctic and Antarctica. Advancements in our understanding of the fate and transport of SOCs in western U.S are hindered by the limited number and scope of past studies, sampling strategies, and current methodologies. Described herein, the development, validation, and as well as the demonstration of a new analytical method capable of measuring 75 SOCs including current and historic-use pesticides, polycyclic aromatic hydrocarbons, polychlorinated biphenyls in large-volume lake water and snowmelt samples. A novel solid phase extraction device containing hydrophilic and hydrophobic called a “modified Speedisk” was developed to handle large volume aqueous samples (50L), capture a wide range of SOCs, and capable of interfacing with an in situ submersible pump. In addition, this dissertation contains the development, validation, and demonstration of an analytical method capable of quantifying 98 SOCs including polybrominated diphenyl ethers from remote lake systems. Sediment core, snow, and lake water samples were collected, extracted, and quantified for SOCs using the methods above from fourteen high-altitude and/or high-latitude remote lake systems in western National Parks (NPs). Many SOCs demonstrated a significant regression between surficial sediment fluxes and snow fluxes (p<0.05). These significant regressions stress the importance of winter time SOC deposition in western NPs. SOC deposition in Rocky Mountain NP and Glacier NP is dependent on regional upslope wind directions and the location of regional sources (relative to the Continental Divide). Lake water concentrations and sediment fluxes were generally lower in the Alaska’s NPs and Olympic NP, due to proximity to source regions and the prevailing westerly winds.
Here we highlight some of the opportunities associated with combining advanced sample preparation techniques with stateof-the-art chemical analysis techniques. This article considers the unique ...combination of selective pressurized liquid extraction (SPLE) with gas chromatography (GC) coupled with mass spectrometry (MS) and ultrahigh-pressure liquid chromatography coupled with tandem MS (UHPLC-MS-MS). We use this powerful combination to develop a novel analytical technique capable of measuring hormones and organic contaminants in whale earwax plugs. We explore the analytical challenges with such combinations and the advantages of focusing both on sample preparation as well as chemical analysis.
Wave packet interferometry provides benchmark information on light-induced electronic quantum states by monitoring their relative amplitudes and phases during coherent excitation, propagation, and ...decay. The relative phase control of soft x-ray pulse replicas on the single-digit attosecond timescale achieved in our experiments makes this method a powerful tool to probe ultrafast quantum phenomena such as the excitation of Auger shake-up states with sub-cycle precision. In this contribution we present first results obtained for different Auger decay channels upon generating L-shell vacancies in argon atoms using Michelson-type all-reflective interferometric autocorrelation at a central free-electron laser photon energy of 274.7 eV.
Here, we use x-rays to create and probe quantum coherence in the photoionized amino acid glycine. The outgoing photoelectron leaves behind the cation in a coherent superposition of quantum mechanical ...eigenstates. Delayed x-ray pulses track the induced coherence through resonant x-ray absorption that induces Auger decay and by photoelectron emission from sequential double photoionization. Sinusoidal temporal modulation of the detected signal at early times (0 to 25 fs) is observed in both measurements. Advanced ab initio many-electron simulations allow us to explain the first 25 fs of the detected coherent quantum evolution in terms of the electronic coherence. In the kinematically complete x-ray absorption measurement, we monitor its dynamics for a period of 175 fs and observe an evolving modulation that may implicate the coupling of electronic to vibronic coherence at longer time scales. Our experiment provides a direct support for the existence of long-lived electronic coherence in photoionized biomolecules.
Quantum coherence between electronic states of a photoionized molecule and the resulting process of ultrafast electron-hole migration have been put forward as a possible quantum mechanism of ...charge-directed reactivity governing the photoionization-induced molecular decomposition. Attosecond experiments based on the indirect (fragment ion-based) characterization of the proposed electronic phenomena suggest that the photoionization-induced electronic coherence can survive for tens of femtoseconds, while some theoretical studies predict much faster decay of the coherence due to the quantum uncertainty in the nuclear positions and the nuclear-motion effects. The open questions are: do long-lived electronic quantum coherences exist in complex molecules and can they be probed directly, i.e. via electronic observables? Here, we use x-rays both to create and to directly probe quantum coherence in the photoionized amino acid glycine. The outgoing photoelectron wave leaves behind a positively charged ion that is in a coherent superposition of quantum mechanical eigenstates lying within the ionizing pulse spectral bandwidth. Delayed x-ray pulses track the induced coherence through resonant x-ray absorption that induces Auger decay and by the photoelectron emission from sequential double photoionization. Sinusoidal temporal modulation of the detected signal at early times (0 - 25 fs) is observed in both measurements. Advanced ab initio many-electron simulations, taking into account the quantum uncertainty in the nuclear positions, allow us to explain the first 25 fs of the detected coherent quantum evolution in terms of the electronic coherence.
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