A5032147593- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Atmospheric aerosols and clouds
- Air Quality and Health Impacts
- Atmospheric Ozone and Climate
- Analytical Chemistry and Chromatography
- Advanced Chemical Sensor Technologies
- Analytical Chemistry and Sensors
- Arctic and Antarctic ice dynamics
- Chromatography in Natural Products
- Advanced biosensing and bioanalysis techniques
- Ocean Acidification Effects and Responses
- Climate change and permafrost
- Crystallization and Solubility Studies
- RNA and protein synthesis mechanisms
- Porphyrin and Phthalocyanine Chemistry
- Marine and coastal ecosystems
- Toxic Organic Pollutants Impact
- Chemical and Physical Properties in Aqueous Solutions
- Oil, Gas, and Environmental Issues
- Drug Solubulity and Delivery Systems
- Odor and Emission Control Technologies
- Protein purification and stability
- Molecular Biology Techniques and Applications
- RNA Interference and Gene Delivery
Merck & Co., Inc., Rahway, NJ, USA (United States)
2020-2025
University of Michigan
2016-2024
Michigan United
2017-2020
Siena College
2011-2012
In freshwater lakes, harmful algal blooms (HABs) of Cyanobacteria (blue-green algae) produce toxins that impact human health. However, little is known about the lake spray aerosol (LSA) produced from wave-breaking in HABs. this study, LSA were laboratory samples collected Lake Michigan and Erie during HAB nonbloom conditions. The incorporation biological material within individual HAB-influenced particles was examined by single-particle mass spectrometry, scanning electron microscopy with...
Inland sources of particulate chloride for atmospheric nitryl (ClNO2) formation remain unknown and unquantified, hindering air quality assessments. Globally each winter, tens millions tons road salt are spread on roadways deicing. Here, we identify aerosol as the primary source, accounting 80–100% ClNO2 formation, at an inland urban area in wintertime. This study provides experimental evidence connection between through production this important reservoir nitrogen oxides chlorine radicals,...
Abstract. Organic aerosol formation and transformation occurs within aqueous cloud droplets, yet little is known about the composition of high molecular weight organic compounds in water. Cloud water samples collected at Whiteface Mountain, New York, during August–September 2014 were analyzed by ultra-high-resolution mass spectrometry to investigate dissolved carbon, with a focus on sulfur- nitrogen-containing compounds. was evaluated context inorganic ion concentrations, pH, total carbon...
Abstract. Long-range aerosol transport affects locations hundreds of kilometers from the point emission, leading to distant particle sources influencing rural environments that have few major local sources. Source apportionment was conducted using real-time chemistry measurements made in July 2014 at forested University Michigan Biological Station near Pellston, Michigan, a site representative remote Great Lakes region. Size-resolved chemical composition individual 0.5–2.0 µm particles...
SignificancePhysical and chemical properties of individual atmospheric particles determine their climate impacts. Hygroscopic inorganic salt mixed with trace amounts organic material are predicted to be liquid under typical tropospheric conditions in the summertime Arctic. Yet, we unexpectedly observed a significant concentration solid composed ammonium sulfate an coating high relative humidity low temperature. These particle consistent marine biogenic-derived new formation growth, collision...
Abstract. Loss of sea ice is opening the Arctic to increasing development involving oil and gas extraction shipping. Given significant impacts absorbing aerosol secondary precursors emitted within rapidly warming region, it necessary characterize local anthropogenic sources compare natural conditions. From August September 2015 in Utqiaġvik (Barrow), AK, chemical composition individual atmospheric particles was measured by computer-controlled scanning electron microscopy with...
Sea spray aerosol (SSA) and lake (LSA) from wave breaking contribute to particulate matter (PM) in coastal regions near oceans freshwater lakes, respectively. However, SSA LSA contributions atmospheric populations inland are poorly understood because of difficulties differentiating them other sources when using bulk particle measurements. Herein, we show that episodically at a rural site northern Michigan >700 >25 km the nearest seawater Great Lakes sources, During July 2014, individual...
Abstract Marine aerosol plays a vital role in cloud‐aerosol interactions during summer the Arctic. The recent rise temperature and decrease sea ice extent have potential to impact marine biogenic sources. Compounds like methanesulfonic acid (MSA) non‐sea‐salt sulfate (nss‐SO 4 2− ), oxidation products of dimethyl sulfide (DMS) emitted by primary producers, are likely increase concentration. Long‐term studies understand these changes sulfur with Arctic climate. Samples were collected over...
The rapid decrease in Arctic sea ice is motivating development and increasing oil gas extraction activities. However, few observations of these local emissions exist, limiting the understanding impacts on atmospheric composition climate. To address this knowledge gap, chemical aerosols was measured within North Slope Alaska fields during August September 2016 using an aerosol time-of-flight mass spectrometer (ATOFMS) a speciation monitor (ToF-ACSM). Plumes from activities were characterized...
Hydroxymethanesulfonate (HMS) is produced in the aqueous-phase reaction of formaldehyde (HCHO) and sulfur dioxide (SO2) has been proposed as a significant contributor to midlatitude wintertime pollution events. Here we report HMS detection within submicrometer atmospheric aerosols during frequent late summer, regional fog events an Arctic oil field. The number fraction individual particles containing increased periods, consistent with formation. single-particle mass spectra showed primary...
A rare example of crystal form-dependent, gamma radiation-induced degradation is presented. Islatravir known to exist in several polymorphic forms, but only one these forms shows the generation a specific dimer product under irradiation. Extended irradiation studies demonstrated that crystalline an appreciable rate formation. Additionally, this not observed form other forced stress conditions. We present structural elucidation impurity and rationalize its form-dependent based on analysis...
Abstract As the Arctic rapidly warms, sea ice extent is decreasing and oil gas extraction activities are expanding. Local combustion emissions affect atmospheric aerosol chemical mixing state (the distribution of species across population), which impacts climate‐relevant properties. Bulk single‐particle measurements submicron aerosols were conducted at Oliktok Point, Alaska within North Slope fields. In this work, we quantify diversity using online mass spectrometry data (32,880 individual...
Nitryl chloride (ClNO2) is formed in urban areas from the multiphase reaction of dinitrogen pentoxide (N2O5) on chloride-containing surfaces. ClNO2 undergoes photolysis to produce atomic chlorine (Cl•), a strong atmospheric oxidant. While previous studies have focused particulate chloride, saline snowpack locations impacted by sea spray and road salt usage represents an additional, potentially large, source ClNO2. Here, we present first modeling study explore production inland snowpack. The...
Abstract. Organic aerosol formation and transformation occurs within aqueous cloud droplets, yet little is known about the composition of high molecular weight organic compounds in water. Cloud water samples collected at Whiteface Mountain, New York during August–September 2014 were analyzed by ultrahigh-resolution mass spectrometry to investigate dissolved carbon, with focus on sulfur- nitrogen-containing compounds. was evaluated context inorganic ion concentrations, pH, total carbon...
Porphyrin containing thin film colorimetric sensors for volatile organic compounds (VOCs) have been synthesized and characterized. Electropolymerization has employed to synthesize robust poly-tetrakis(4-aminophenyl)porphyrin films. Production of films by this method allows fine control over thickness allowing rapid responses analytes. While many techniques used produce rely on electrostatics, these are covalently linked, yielding excellent structural integrity upon repeated exposure...
Abstract Selection of column and mobile phase eluent/buffer is a crucial step in chromatographic method development. The introduction new technologies requires continuous performance evaluation enabling the deployment improved screening workflows. Consequently, development universal that could be used across different chemistries pH ranges would highlighted as advantageous. Herein, we introduce single generic probe developed via software‐based modeling delivers excellent results for...
Abstract. Long-range aerosol transport affects locations hundreds of kilometers from the point emission, leading to distant particle sources influencing rural environments that have few major local sources. Source apportionment was conducted using real-time chemistry measurements made in July 2014 at forested University Michigan Biological Station near Pellston, Michigan, a site representative remote Great Lakes region. Size-resolved chemical composition individual 0.5–2.0 μm particles...
The identification, quantification, understanding, and control of impurities in starting materials, intermediates, substances are crucial during the evaluation new molecular entities clinical development pharmaceutical industry. Through process characterization islatravir (MK-8591), two from regulatory material, TMS-Triol, were discovered a late stage that persisted product. However, they not detectable by gas chromatography (GC) method used. This paper describes use orthogonal analytical...