chemistry

Chromatography is the separation of a mixture of compounds into individual components. There are three major steps involved with separating and identifying components of a mixture using a GC-MS. They are: Injecting a sample into the GC inlet Separating the sample into individual components Detecting the compounds present in the sample. This is done in the detector. In the video shown below, the detector is a mass spectrometer . Chromatography using a GC or GC-MS has been described in previous posts: Gas chromatography The Injection System in GasChromatography – Sample Introduction Understanding Columns in GasChromatography Gas Chromatography Detectors How does a mass-spectrometer work? A GC-MS analytical instrument equipped with an autoinjector is shown in the following video. A sample is automatically injected into the GC inlet and separation and identification of its constituents takes place.     https://www.youtube.com/watch?v=R4sITWA8xrc

Solutions and Concentration - Solution Composition Chemical reactions often take place in aqueous solutions. To perform stoichiometric calculations in such cases the amounts of chemicals present in solution – the concentration of solution - must be known. Concentration of a solution is a measurement stating the amount of a solute present in a known amount of solution: Concentration = amount of solute / amount of solution The terms solute and solution are usually used for liquid samples but they can be extended to gaseous and solid samples. The most common units of concentration are given in Table I.1: Common Units of