Organic Analysis

1. Honors Forensic Science Organic Analysis

2. I. Elements and Compounds • A. Matter = anything that has mass and occupies space • B. Element = cannot be broken down into simpler substances by chemical means • i. Listed in periodic table • Ii. 98 naturally occurring elements

3. C. Periodic table = chart of elements arranged in a systematic fashion • i. Vertical rows are called groups or families • Ii. Horizontal rows are called series • Iii. Elements in a given row have similar properties

4. D. Atom = smallest particle of an element that can exist and still retain its identity as that element • E. Compound = a pure substance composed of two or more elements • i. 6 million known compounds

5. II. Physical states • A. Solid = rigid and has definite shape and volume • B. Liquid = occupies specific volume, but fluidity causes it to take shape of container it is in • C. Gas (vapor) = neither definite shape or volume

6. D. Substances change from one state to another • E. Sublimination = physical change from the solid directly into the gaseous state • F. Phase = a uniform piece of matter, different phases are separated by definite visible boundaries

7. III. Selecting an Analytical Technique • A. To select a technique, need to know whether substance is organic or inorganic • I. Organic = substance composed of carbon and hydrogen • Ii. Inorganic = CO2 and all substances that lack carbon • Iii. Also, need to consider the need for qualitative and quantitative determination

8. IV. Analytical Technique • A. Spectrophotometry • i. An analytical method for identifying a substance by its selective absorption of different wavelengths of light • Ii. Most applicable to organic analysis • Iii. Optimum utilization requires that a material be in relatively pure state

10. b. Chromatography • i. Any of several analytical techniques whereby organic mixtures are separated into their components by their attraction to a stationary phase while being propelled by a moving phase • Ii. Useful technique for purifying substances

12. Iii. Behavior first observed in 1803 by William Henry (Henry’s Law) • Iv. During process, one phase is always made to move continuously in one direction over a stationary or fixed phase

13. V. Is like a race between chemical compounds; at the beginning, all substances are mixed together; as race progresses, those that have preference for moving phase will move faster and pull ahead of others; at end, all substances separated

15. vi. Gas Chromatography • 1. separates mixtures on the basis of their distribution between a stationary liquid phase and a moving gas phase • 2. used widely because of its ability to resolve a highly complex mixture into its components within a time period usually measured in minutes

16. 3. is very sensitive • 4. sample must be vaporized and passed through heated tube

19. vii. High-performance liquid chromatography • 1. liquid is moving phase • 2. can perform process at room temperature • 3. used for organic explosives and drugs that are heat sensitive

20. viii. Thin-layer Chromatography • 1. incorporates solid stationary phase and moving phase to effect separation of constituents of mixture • 2. because most compounds are colorless, use UV light to reveal those that fluoresce • 3. cannot by itself provide absolute identification; has to be used in conjunction with other procedures to prove absolute identity

21. 4. powerful tool for solving analytical problems • 5. rapid and sensitive • 6. minimal cost and space requirements

23. ix. Electrophoresis • 1. related to TLC in that it separates materials according to their migration rates on solid phase • 2. uses electrical current instead of moving liquid phase • 3. characterization of proteins, enzymes, and DNA