320 likes | 1.44k Views
Organic Analysis. Basic concepts. Elements and Atoms. Fundamental building block of all substances is the element. Atom smallest particle of an element that can exist but retain identity as that element. The Periodic Table. All elements are listed systematically.
E N D
Organic Analysis Basic concepts
Elements and Atoms • Fundamental building block of all substances is the element. • Atom smallest particle of an element that can exist but retain identity as that element.
The Periodic Table • All elements are listed systematically. - elements are arranged according to similar properties. • groupscontain elements with similar properties in vertical columns. • periods are horizontal rows of elements.
Periodic table G R O U P S P E R I O D S
What are Compounds? • A compound is combination of at least 2 elements. • Compounds have different physical and chemical properties than either element alone. Eg. Ag2S, CO2
Physical States of Matter • Matter is classified into three physical states SOLID LIQUID GAS (VAPOR) • Substances can change from one state to another eg. sublimation, freezing, evaporation, condensation.
Phases of matter • Different phases are formed when two substances will not mix. Eg. oil and water.
Chemical Bonds Attractive forces that hold the atoms or molecules of a substance together. Solids have strong attractive forces but gases have weak bonds allowing the molecules to move in any and all directions.
Organic and Inorganic Analysis Organic substances always contain the element carbon. Everything else is inorganic! • Properties of organic and inorganic materials are very distinct therefore they require different types of tests.
Qualitative versus Quantitative testing. • Qualitative (think “quality”) tests state the identity only eg. Heroin and quinine. • Quantitative (think “quantity”) also determines how much there is, either % or weight. Eg. Heroin sample- 90% heroin and 10% quinine.
Analysis of Organic Materials. • Common analytical techniques: 1. Spectrophotometry 2. Chromatography
Chromatography • Useful for analyzing samples with many different components eg. Drug mixtures. • Theory: chemical substances tend to partially escape into the surrounding environment when dissolved in liquid OR absorbed on a solid surface.
Terminology • Equilibrium : point where the number of molecules leaving the liquid phase = number of molecules entering the liquid phase i.e. no further change • Partitioning : movement/dissociation to liquid or gas phase is determined by the solubility of the gas in the liquid.
Terminology • Moving and Stationary phases : In chromatography one phase is always moving (“moving phase”) over another (“stationary phase”). SOLID LIQUID GAS • Different types of chromatography vary in both their stationary and moving phases.
H.P.L.C. and G.C. H.P.L.C. High Performance Liquid Chromatography G.C. Gas Chromatography
Gas Chromatography (G.C.) The component with the greatest affinity for the moving phase (i.e. gas) will travel through the column faster separation of the mixture’s components.
Chromatograms • The detector records the separation of the different components of the mixture as a function of time. • Each peak is one component of the mixture. • Time required for the peak to emerge is called the retention time
Pyrolysis Gas Chromatography • High temps (500-1000oC) will decompose solid materials to gaseous products that can be analyzed by the G.C. • Chart of different components of the mixture is called a pyrogram.
High Performance Chromatography (H.P.L.C.) • takes place at room temperature. • Sample components are retarded to different degrees depending on their interaction with the stationary phase. • Useful for analysis of organic explosives and heat sensitive drugs.
Thin Layer Chromatography • Solid samples are dissolved in a solvent prior to analysis, then “spotted” onto the solid support. • Components with the greatest affinity for the moving phase (liquid solvent) will move farthest. • Visualize spots with fluorescent dye or other chemicals.
Calculation of Rf value • Identification involves running a known/authentic sample on the same T.L.C. plate. Rf = distance traveled by the component distance traveled by the moving phase
Thin Layer Chromatography • Advantages: 1. Used for mixtures eg. drugs which are not pure. 2. Small amount of sample….approx. 100ug. 3. Can run multiple samples simultaneously.
Gel Electrophoresis • Separates mixtures according to their size and charge as determined by migration within an agarose gel which has an electrical current running through it. • Used to separate complex biochemical mixtures eg. proteins and DNA. • Separate components appear as “bands” on the gel.