Instrumentation used to quantify environmental analytes

        1.  Spectrophotometric Techniques -  based on light absorption
            a.  UV/Vis Spectrophotometry  -  (phosphate, silica)
             b.  Atomic Absorption Spectrophotometry  - (metals)
             c.  Infra-red gas analysis   -   (TOC)

        2. Chromatographic techniques  -  (separations)
            a. High Performance Liquid Chromatography 
                                (polar organics - many pesticides) 
                 1. Ion chromatography (anions)
            b. Gas chromatography (nonpolar organics - chlorinated hydrocarbons)
 
        3. Potentiometric techniques -  Analyte forms electrical circuit w/ sensor
            a.  Ion-selective electrodes - pH, DO, F^-, etc.
                 b.  Potentiometric Titrations  - Alkalinity

        4. Mass spectrometry  - often as detector coupled to others (e.g. GC/MS)
                          molecule broken up into characteristic fragments