Analytical Chemistry Flashcards
What is Absorption Spectroscopy?
Analyzes the energy absorbed by the sample to excite an atom or molecule to an excited state
-frequency corresponding to difference in energy levels will be absorbed
What are the uses of Infared Spectroscopy?
Confirm presence of functional groups
E.g level of alcohol
Degree of unsaturation of oils and fats
Mass Spectroscopy?
Actual structure of a compound from fragmentation patterns
Nuclear Magnetic Resonance spectroscopy
Provides information on the chemical environment of hydrogen atoms in the molecule
Atomic Absorption Spectroscopy
Energy absorbed by the electrons as they are promoted from a lower to higher energy level that is measured
-identify exact concerntration
How do you determine the concentration of an element?
There is a direct relationship between the amount of light absorbed and the concentration of the element in the path of light
Chromatography usage?
To separate mixtures containing very small amounts of the individual components + purity
Adsorption
The more tightly the component is adsorbed the slower it will elute
Partition
The more soluble or volatile the component in the mobile phase the faster it will elute
Factors affecting he color of transition metal complexes (4things)
- Nature of the transition element
- The oxidation state
- The identity of the ligand
- The shape of the molecule
What region do organic molecules absorb in? Double bonds?
Ultraviolet
If there are a lot of double bonds less energy required and absorption in the Visible region
Tetramethylsilane?
All protons in same environment
Not toxic or reactive
Volatile-easily removed
Absorbs upfield
Gas-liquid Chromatography usage?
Separate and identify components present in mixtures of volatile liquids that do not decompose near boiling points
-detect alcohol concentration in urine
High-Performance Liquid Chromatography (HPLC)
Useful for non-volatile componenets
-oil samples, vitamins, separate enantiomers
Gas Chromatography with Mass spectrometry
Used to detect and measure the conc. of extremely small samples of subtances
