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Volatile Organic Compounds: Organic compounds that have a relatively high Vapor pressure at room temperature.

PTR-ToF-MS Coupled with an Automated Sampling System and Tailored Data Analysis for Food Studies: Bioprocess Monitoring, Screening and Nose-space Analysis

1Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach (FEM), 2Faculty of Science and Technology, Free University of Bolzano, 3Department of Agriculture, Food and Environmental Sciences, University of Foggia, 4Institute of Analytical Chemistry & Radiochemistry, Leopold-Franzens Universität Innsbruck, 5Institut für Ionenphysik und Angewandte Physik, Leopold-Franzens Universität Innsbruck

JoVE 54075


Determination Of NOx in Automobile Exhaust Using UV-VIS Spectroscopy

JoVE 10076

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University

In the troposphere, ozone is naturally formed when sunlight splits nitrogen dioxide (NO2):

NO2 + sunlight → NO + O

O + O2 O3 Ozone (O3) can go on to react with nitric oxide (NO) to form nitrogen dioxide (NO2) and oxygen: NO + O3 → NO2 + O2 This results in no net gain of ozone (O3). However, with the anthropogenic production of ozone forming precursors (NO, NO2, and volatile organic compounds) through the combustion of fossil fuels, elevated levels of ozone in the troposphere have been found. Motor vehicle exhaust is a significant source of these ozone forming precursors: NO, NO2, and volatile organic compounds (VOCs). For example, mobile sources make up nearly 60% of NO + NO2 emissions. At the high temperatures found in a car’s combustion chamber, nitrogen and oxygen from the air react to form nitric oxide (NO) and nitrogen dioxide (NO2):

 Environmental Science

Gas Chromatography (GC) with Flame-Ionization Detection

JoVE 10187

Source: Laboratory of Dr. B. Jill Venton - University of Virginia

Gas chromatography (GC) is used to separate and detect small molecular weight compounds in the gas phase. The sample is either a gas or a liquid that is vaporized in the injection port. Typically, the compounds analyzed are less than 1,000 Da, because it is difficult to vaporize larger compounds. GC is popular for environmental monitoring and industrial applications because it is very reliable and can be run nearly continuously. GC is typically used in applications where small, volatile molecules are detected and with non-aqueous solutions. Liquid chromatography is more popular for measurements in aqueous samples and can be used to study larger molecules, because the molecules do not need to vaporize. GC is favored for nonpolar molecules while LC is more common for separating polar analytes. The mobile phase for gas chromatography is a carrier gas, typically helium because of its low molecular weight and being chemically inert. Pressure is applied and the mobile phase moves the analyte through the column. The separation is accomplished using a column coated with a stationary phase. Open tubular capillary columns are the most popular columns and have the stationary phase coated on the walls of the capillary. Stationary phases a

 Analytical Chemistry

Measuring Tropospheric Ozone

JoVE 10024

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University

Ozone is a form of elemental oxygen (O3), a molecule of three oxygen atoms bonded in a structure that is highly reactive as an oxidizing agent. Ozone occurs in both the stratosphere and the troposphere levels of the atmosphere. When in the stratosphere (located approximately 10-50 km from the earth’s surface), ozone molecules form to the ozone layer and help prevent harmful UV rays from reaching Earth’s surface. In lower altitudes of the troposphere (surface - approximately 17 km), ozone is harmful to human health and is considered an air pollutant contributing to photochemical smog (Figure 1). Ozone molecules can cause damage directly by harming respiratory tissue when inhaled or indirectly by harming plant tissues (Figure 2) and softer materials including tires on automobiles. Outdoor tropospheric ozone is formed at ground level when nitrogen oxides (NOx) and volatile organic compounds (VOCs) from automobile emissions are exposed to sunlight. Consequently, health concerns over ozone concentrations escalate in sunny conditions or when and where automobile use is increased. Reaction: NO2 + VOC + sunlight &

 Environmental Science

Effects of Exposure of Formaldehyde to a Rat Model of Atopic Dermatitis Induced by Neonatal Capsaicin Treatment

1Neuroscience Research Institute & Department of Physiology, College of Medicine, Korea University, 2Department of Pharmaceutics and Biotechnology, College of Medical Engineering, Konyang University, 3Division of Biological Science and Technology, Science and Technology College, Yonsei University Wonju Campus

JoVE 55987

 Immunology and Infection

3D Printing of Biomolecular Models for Research and Pedagogy

1Department of Physics, Brandeis University, 2Bioinformatics and Computational Biosciences Branch (BCBB), NIH/NIAID/OD/OSMO/OCICB, 3Library/LTS/MakerLab, Brandeis University, 4Interfaculty Institute of Biochemistry (IFIB), University of Tübingen, 5Winship Cancer Institute, Emory University School of Medicine

JoVE 55427


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