24 Chromatography - Summary.pdf

Chromatography Chromatography & Instrumentation in Organic Chemistry Chromatography : separate mixtures such as dyes. Chromatography uses 2 phases: Rf = 1. A stationary phase Distance travelled by the component Distance travelled by the solvent front 2. A mobile phase Method Stationary phase Mobile...

Chromatography Chromatography & Instrumentation in Organic Chemistry Chromatography : separate mixtures such as dyes. Chromatography uses 2 phases: Rf = 1. A stationary phase Distance travelled by the component Distance travelled by the solvent front 2. A mobile phase Method Stationary phase Mobile phase Paper chromatography Water on paper Liquid Thin layer chromatography Solid Liquid Column chromatography Solid Liquid Instrument Principles Processes Uses Drug Testing Gas Chromatograph y Different components of a mixture have different interactions with the stationary and mobile phases Injection Transport of the sample along the column Separation in the column Detection High Performance Liquid Chromatograph y Different components of a mixture have different tendencies to adsorb onto very fine particles of a solid in the HLPC column Injection Transport of sample along column Separation in column Detection the the the Analysis of growth promoters in food Analysis of vitamins in food Chromatography Atomic Absorption Spectrometer Ground state atoms of an element absorb light characteristic of that element. Absorbance is directly proportional to concentration. Sample solution is sprayed into a flame & the sample element is converted into atoms of that element. Ground state atoms absorb radiation from a source made from that element. Finding the concentration of heavy metals in water (lead, mercury, cadmium) Absorbance is measured. Mass Spectrometer Infrared Spectrometer Positively charged ions are separated on the basis of their relative atomic masses in a magnetic Йeld Molecules of a substance absorb infrared light of diАerent frequencies. The combination of frequencies absorbed is peculiar to the molecules of that substance Vaporisation Ionisation Acceleration Separation Detection Analysis of gases from a waste dump Organic pollutants in water Infrared radiation passes through the sample. Sample absorbs infrared radiation at specific wavelengths which are detected. Identification of organic compounds (drugs + plastics) An absorption spectrum is obtained. Ultraviolet Absorption Spectrometer Absorption of radiation by molecules results in the promotion of electrons from their ground state energy levels to higher energy states. Absorbance is directly proportional to concentration. UV light is passed through the sample and a blank. An absorption spectrum is obtained. Analysis of drugs and plant pigment