ABSTRACT
CONTENTS 23.1 Introduction ..................................................................................................................... 600
23.1.1 Physicochemical, Toxicological, and Ecological Aspects ........................... 601 23.1.2 Regulations......................................................................................................... 606 23.1.3 Analytical Process ............................................................................................. 606
23.1.3.1 Sampling and Preservation of Samples........................................ 606 23.1.3.2 Analytical Methods.......................................................................... 607 23.1.3.3 Detectors, Columns, and Gas Chromatography Conditions .... 608
23.2 Headspace Extraction Techniques ............................................................................... 609 23.2.1 Static Headspace ............................................................................................... 609
23.2.1.1 Factors Affecting the Technique.................................................... 609 23.2.1.2 HS Limitations and Advantages ................................................... 618
23.2.2 Purge and Trap.................................................................................................. 618 23.2.2.1 Purge, Trap, and Desorption Processes: Factors
Affecting the Technique.................................................................. 621 23.2.2.2 P&T Limitations and Advantages................................................. 628
23.3 Sorptive Extraction Techniques.................................................................................... 628 23.3.1 Solid-Phase Microextraction............................................................................ 629
23.3.1.1 Extraction: Absorption .................................................................... 629 23.3.1.2 Desorption......................................................................................... 637 23.3.1.3 SPME Limitations and Advantages .............................................. 638
23.3.2 Stir Bar Sorptive Extraction............................................................................. 639 23.3.2.1 SBSE Advantages and Limitations................................................ 639
23.4 Membrane Extraction Techniques ............................................................................... 639 23.5 Solvent Extraction Techniques ..................................................................................... 643
23.5.1 Liquid-Liquid Extraction................................................................................. 643 23.5.2 Single-Drop Microextraction ........................................................................... 649
23.5.2.1 Factors Affecting the Technique.................................................... 650 23.5.2.2 SDME Limitations and Advantages ............................................. 651
23.5.3 Liquid-Phase Microextraction......................................................................... 651 23.5.3.1 Factors Affecting the Technique.................................................... 652 23.5.3.2 LPME Limitations and Advantages.............................................. 652
23.6 Other Techniques............................................................................................................ 652 23.7 Conclusions...................................................................................................................... 653 References ................................................................................................................................... 653
Volatile organic compounds (VOCs) are a group of contaminants of prime concern in water analysis. Many of those compounds are pollutants that not only contribute to environmental degradation processes such as stratospheric ozone depletion and tropospheric ozone formation, but also contaminate water reservoirs. The oxidation of VOCs in the presence of nitrogen oxides leads to the formation of photochemical smog, which is harmful to humans, animals, and vegetation. The problem has been considered of such magnitude that the governments have taken important decisions in order to reduce the emission of these compounds, such those taken in Montreal Protocol [1].
