ResourcesApplication Notes

Residual Solvent Analysis of Chemical Products by GC-FID with Hydrogen as a Carrier Gas

In this application note we will successfully validate a method for the analysis of residual solvents by GC-FID. A technical grade active ingredient (eugenol) will also be tested.

ASTM D6729, Determination of Individual components in spark ignition engine fuels by 100 metre capillary high resolution gas chromatography

Scion Instruments offers the solution for detailed hydrocarbon analysis (DHA). Spark ignition engine fuels consists out of hundreds of hydrocarbon compounds, with this method according to ASTM D6729 these components can be distinguished and analysed. The ASTM D6729 describes a standard test method for individual components in spark ignition engine fuels by high resolution gas chromatography.

Determination of Free Glycerol Content in Fatty Acid Methyl Esters (FAME) and Biodiesel According to EN-14106

Biodiesel is produced by transesterification of the parent oil or fat with an alcohol, usually methanol, in the presence of a catalyst, usually potassium hydroxide or sodium hydroxide, or, increasingly, alkoxides. The resulting product can contain not only the desired alkyl ester product but also unreacted starting material mono-, di- and triacylglycerides, residual alcohol and catalyst...

Analysis of 2,4-DNPH Derivatized Aldehydes by HPLC-DAD

Aldehydes are important compounds regularly use in the chemical industry. Sick house syndrome is a medical condition caused by poor air quality in enclosed indoor spaces and the presence of specific volatile organic compounds (VOCs) such as formaldehyde. It is vital that the level of formaldehyde and associated compounds are regularly measured and controlled especially in working environments in which formaldehyde is handled. SCION Instruments developed a method for the simultaneous analysis of seven DNPH (2,4- Dinitrophenylhydrazine) derivatised aldehydes plus one derivatised ketone.

Monitoring 57 Ozone Precursors in Ambient Air

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.

EPA 8260: Analysis of Volatile Organic Compounds by GC-MS

The United States Environmental Protection Agency (US EPA) was established in 1970 with the aim to protect human health and the environment. Since then environmental contamination has been at the forefront of government policy and regulation through US EPA methods for the analysis of environmental pollutants. EPA 8260 is the standard method for the analysis of volatile organic compounds (VOCs) in ground water and solid waste by purge and trap (P&T) gas chromatography with mass spectrometry (GC-MS). EPA 8260 is a comprehensive method with more than 100 VOCs in the target compound list.

The Determination of Vehicle Emissions in Exhaust Gases and Ozone Precursors in Ambient Air with a Built-in Preconcentrator/GC System

Internal combustion engine emissions are comprised of a long list of organic compounds from C2 to C12 hydrocarbons. Major sources of these are automobiles and trucks with lesser sources including industrial emissions and home powered tools such as lawnmowers and leaf blowers. These emissions are considered as ozone precursors in the ambient air since under atmospheric conditions in the summer months, they can interact with nitrogen oxides in the presence of sunlight to produce ozone, a criteria air pollutant under the United States Clean Air Act (1970). The amount and identity of the saturated and unsaturated organics that make up the ozone precursors has a major impact on the amount of ozone produced since each precursor has a certain ozone formation potential. Concentration at the tailpipe of an automobile are much greater than those found in the ambient air, so any analytical system must be capable of analysing a wide range of concentrations. A custom SCION GC system combining a special preconcentrator and dual FID was used to evaluate a standard gas mixture which contained target precursors from C2 to C13 hydrocarbons.

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

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. The SCION helium free analyser will ensure safe routine operation, with no performance change when operating under EPA Method 8270 specifications. SCION’s unique axial ion source provides excellent robust operation and minimises unwanted protonation and spectral distortions. In addition, the GC with split/splitless (SSL) injector and inert pathway prevent compound degradation and reactions with the hydrogen carrier gas. This application note demonstrates the exceptional performance of the SCION GC-MS when operated under Method 8270 specifications.

Analysis of Mineral Oils Utilising Temperature Programmed Large Volume Injection

Mineral oil hydrocarbons are typically found in water, foods and soils. These hydrocarbons can be extracted using a variety of solvents, with the most popular being hexane and petroleum ether. As concentrations can be very low, sample enrichment is often required. However, SCION instruments developed a method that simply uses a Large Volume Injection (LVI) technique to simplify sample pre-treatment whilst dramatically increasing throughput. The Hydrocarbon Index (HOI) is the total amount of compounds which can be extracted from water samples using a non-polar solvent. The solvent must have a boiling point between 39℃ and 69℃, thus replacing the use of halogenated solvents. Halogenated solvents and high concentrations of polar substances can interfere with the determination of the HOI. In addition, the compounds must not absorb on Florisil and must elute between ndecane and n-tetracontane. The method is suitable for HOI determinations in concentrations above 0.1mg/L in water samples. This application note describes the highly efficient analysis of mineral oil hydrocarbons in water using the SCION 456 GC equipped with a Programmable Temperature Vaporiser (PTV). The system is very well suited to the DIN-EN-ISO 9377 method.

AN0023_US EPA Method TO-15 Volatile Organic Compounds in Ambient Air

Many volatile organic compounds (VOCs) that occur in ambient air are the result of emissions from mobile, industrial sources, landfills and hazardous waste sites. The levels of these compounds in air frequently regulated by national or local government agencies. Additionally, it is vital to monitor the VOCs to determine the effect they have on human health, the environment and the global climate. Detection of toxic organic compounds in ambient air is undoubtedly one of the most difficult analyses in gas chromatography, due to the trace levels needed to be quantified and due to the large number of target compounds. Samples must be concentrated into a small volume in order to enhance detection limits.