English PRODUCTS + SOLUTIONS + KNOWLEDGE + SERVICES & SUPPORT + ABOUT US + CONTACT US CONTACT US RESOURCES NEWS Learn About Process Gas Chromatography What is Process Gas Chromatography? Why Choose Us for Process Gas Chromatography? Process Gas Chromatography FAQ Process Gas Chromatography Glossary AMETEK MOCON » KNOWLEDGE » Learn About Process Gas Chromatography » Process Gas Chromatography Glossary Process Gas Chromatography Glossary A Accuracy: The difference between the maximum and minimum measurements of 5 analyses of a known standard. Max Deviation (%) – Min Deviation (%) B BTEX: Benzene, Toluene, Ethylbenzene and Xylene. Aromatic hydrocarbons. Common carcinogenic VOC’s frequently found in combustion exhaust. C Carrier gas: A pure gas used to drive sample through the GC process. Typically Nitrogen, Hydrogen or Helium Chromatogram: The graphical results from a GC analysis. Column: The portion of a gas chromatograph which allows various gasses present in a sample to separate into their constituent parts. See our FAQ titled: How does a GC work / what’s the difference between total and GC analysis Concentration (%, ppm, ppb, ppt): Per Cent, Parts per Million, Parts per Billion and Parts per Trillion. 10% = 100,000 ppm. 10 ppm = 10,000 ppb. 10 ppb = 10,000 ppt D Drift: The difference in response to a known standard measured 24 hours apart. [( Initial Cal – 24 Hour Cal ) / ( Cal Value )] * 100 Dwell: The period of time that a multi-point sampling system spends monitoring a given point. E eV: Electron Volt. A measure of the energy of a photon. Closely related to the frequency and wavelength of light. F FID: Flame-Ionization Detector. A gas detector which uses a hydrogen flame to displace and collect electrons from a sample. Typically used for hydrocarbons. G GC: Gas Chromatograph. A device used to measure both composition and concentration of a gas sample I Ionization Potential: A measure of energy required to free an electron from a given atom or molecule. See eV. M MDQ: Minimum Detectable Limit. The lowest concentration a given detector can quantify. Method: The Analytical Method. The method defines all the fixed parameters within a given analysis. Column temperature, carrier gas flow rate, injection timing, concentration alarm levels and calibration information are all examples of Method parameters. P Permanent Gas: A class of gasses which will condense except at extremely low temperatures. E.G.: Hydrogen, Oxygen, Nitrogen and Carbon Monoxide. PID: Photo-Ionization Detector. A gas detector which uses high energy ultra-violet light to displace and collect electrons from a sample. Typically used for VOCs. PLC / DCS: Programmable Logic Controller / Data Collection System. Computerized devices which collect information from various locations in a process and make control decisions based on this information PSI: Pounds per Square Inch. A measure of gas pressure commonly used in the US R Repeatability: The % Relative Standard Deviation of the measurements of 5 consecutive measurements. [ Std Dev ( Conc1 … Conc5 ) / Average ( Conc1 … Conc5 ) * 100 S Sample loop: A length of tubing used to collect and inject a fixed volume of sample into a column. See our FAQ titled: How does a GC work / what’s the difference between total and GC analysis Sequence: Multi-port Sequence. The sequence defines which sample locations will be monitored and in what order. This gives the user flexibility to monitor higher risk areas more frequently. T TCD: Thermal Conductivity Detector. A universal gas detector which measures the difference in thermal conductivity between a sample and reference gas stream to determine sample content. THA: Total Hydrocarbon Analyzer: A device used to measure the total hydrocarbon content of a gas sample. This device does not measure composition of the sample. V VOC: Volatile Organic Compound. A broad class of chemicals which evaporate easily at room temperature and typically have ionization potentials below 10.6 eV. See BTEX for some examples. W WITS: Wellsite Information Transfer Standard. A data protocol standard used to provide real time data to oil exploration drilling rigs. SHARE WITH YOUR NETWORK PRODUCT BRANDS MOCON Dansensor Baseline KNOWLEDGE Resource Library Learn About Permeation Learn About Modified Atmosphere Packaging Learn About Process Gas Chromatography SERVICES & SUPPORT Consulting & Testing Services Performance Service Spare Parts & Consumables ABOUT US About AMETEK MOCON News & Events Careers Contact Us Subscribe to Newsletter Follow Us Privacy Policy Ametek.com SITE MAP Regulatory Legal Unsubscribe Partner Portal Academy News & Events ©2020 AMETEK MOCON All rights reserved. Continuous product development may make it necessary to change details without notice. By continuing to use the site, you agree to our Privacy and Cookie Policy. Ok