Showing 61 - 70 of 86 results

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Monitoring 57 Ozone Precursors in Ambient Air [AN0036]

Ozone, or trioxygen, is a gas made up of three oxygen atoms (O3). Naturally occurring in the stratosphere (upper atmosphere), ozone protects life on Earth from the Sun’s ultraviolet (UV) radiation. However, the tropospheric ozone formation occurs when nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs) react in the atmosphere in the presence of sunlight, specifically the UV spectrum. NOx, CO and VOCs are known as the ozone precursors. These ozone precursors cause a negative impact on plants and animals. Although VOCs are naturally emitted by biological organisms, NOx and VOCs are emitted during combustion of farming equipment and burning of biological materials.
It is vital that the environment is not only protected from these ozone precursors but the level of ozone precursors are monitored. The United States Air Cleansing Act (1970) empowered the Environmental Protection Agency (EPA) to maintain air cleanliness and protect public health. EPA requires states in the US to identify problematic areas through comprehensive monitoring of NOx, CO and VOCs (known as Photochemical Assessment Monitoring Stations; PAMS). In the PAMS monitoring program, there are 57 specified target compounds, mainly non-methane hydrocarbons ranging from C2 to C12. This application note describes the process for monitoring these 57 ozone precursors in ambient air.

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Optimal Quantification of THC in Blood, May 2019.1 [AN014]

INTRODUCTION: The number of regular cannabis users in the world is estimated at 183 million people[1]. It is illegal to drive a vehicle whilst under the influence of cannabis. The active ingredient in cannabis is delta9-Tetrahydrocannabinol (Δ9-THC). Common side effects includes the feeling of euphoria, hallucinations, relaxation and even sedation. Post ingestion, Δ9-THC is metabolised into the inactive ingredient Tetrahydrocannabinolic Acid (THCA/ THCCOOH).

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Performance of EPA Method 8270 using Hydrogen Carrier Gas on SCION GC-MS, May 2019.1 [AN018]

INTRODUCTION: United States Environmental Protection Agency (USEPA) Method 8270 is an analytical method for the detection of semi-volatile organic compounds in solid waste matrices, soils, air sampling media and water samples, by gas chromatography with mass spectrometry (GC-MS). The method measures a mixture of acids, bases and neutrals in sample extracts. The complexity of these extracts demand a robust instrument that is easy to operate and
maintain. Adding to method complexity is the uncertainty in both cost and supply of helium, forcing laboratories to consider hydrogen as a carrier gas. Hydrogen is not an inert gas; it is reactive and can be an explosion hazard if allowed to build up in the GC oven or manifold of the MS.

Showing 61 - 70 of 86 results