Emissions Sampling & Analysis
Building Materials, Furniture, Consumer Goods, Construction Adhesives
High Performance Liquid Chromatography - UV/Vis, Fluorescence Detectors
These conditions are important when using retention time to identify components within a sample. Once the components of the sample are separated and leave the column the compounds are detected.
The HPLC’s UV-Vis detector measures the absorption of a sample in the ultraviolent-visible spectrum at various wavelengths to identify analytes. Fluorescence detectors are more sensitive and selective, exciting a specific molecule. The emitted wavelength is a property characteristic of a specific compound.
Gas Chromatography with Mass Spectrometry - FID, ECD, & NPD Detectors
GC/MS is an analytical method that is used to identify and detect various analytes and substances by gas chromatography and mass spectrometry.
The GC volatizes the sample into a gas phase and separates the compounds using a column packed with a stationary (solid) phase. The compounds are moved by a carrier gas, causing each one to exit the column at various times (retention times). The separated compounds leave the column and enter the mass spectrometer.
The MS turns the compounds into ionized fragments. The compounds are passed through a high energy beam of electrons to produce ions. The ions are electrically charged atoms or molecule with a net electric charge due to loss or gain of one or more electrons. Each ion has a mass, and the mass of the ion is divided by the charge giving a mass to charge ratio. The ionized fragments are exposed to a magnetic field then travel to the detection plate. The mass to charge ratio is plotted against the intensity of the signal and compared to a library which allows the compound to be identified. The compounds can be identified using a combination of their retention time and their mass spectrum.
Thermal Desorption Gas Chromatography with Mass Spectrometry
TD-GC/MS is the process of heating a sample such that volatile compounds can be removed from a solid matrix. This concentrates the analytes so that they are then able to be separated and characterized using GC/MS.