ABSTRACT
CONTENTS 21.1 Introduction ..................................................................................................................... 563
21.1.1 Properties and Relevance................................................................................ 563 21.1.2 Analysis.............................................................................................................. 564 21.1.3 Internal Standard Quantification Method.................................................... 566
21.2 Principles behind the Method ...................................................................................... 568 21.3 Sampling........................................................................................................................... 569
21.3.1 Preliminary Remarks ....................................................................................... 569 21.3.2 Suspended Particulate Matter ........................................................................ 569 21.3.3 Dissolved Fraction............................................................................................ 570
21.4 Extraction ......................................................................................................................... 572 21.4.1 Preliminary Remarks ....................................................................................... 572 21.4.2 Extraction from Liquid Matrices.................................................................... 572 21.4.3 Extraction from Solid Matrices ...................................................................... 572
21.5 Cleanup ............................................................................................................................ 572 21.6 Instrumental Analysis .................................................................................................... 574
21.6.1 Gas Chromatography ...................................................................................... 574 21.6.2 Mass Spectrometry........................................................................................... 574 21.6.3 Identification and Quantification of Congeners.......................................... 575
21.7 Data Reporting ................................................................................................................ 575 References ................................................................................................................................... 576
21.1.1 Properties and Relevance
Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) [1,2] are environmental pollutants particularly relevant for their toxicity. Their structure formulas are shown in Figure 21.1. Each of the carbon atoms at the 1,2,3,4-, and 6,7,8,9-positions can bond either with chlorine or with hydrogen atoms, so yielding 210 possible congeners (75 PCDDs and 135 PCDFs), different in the number and/or position of chlorine atoms. The PCDDs and PCDFs are chemically and thermally stable and very persistent in the
environment. More important, the 17 congeners (7 PCDDs and 10 PCDFs) bearing chlorine atoms at the 2,3,7,8-position are considered to be carcinogenic (the 2,3,7,8-T4CDD has been classified as carcinogenic to humans by International Agency for Research on Cancer (IARC)) [3] and endocrine disrupting agents [4] consequently, only these 17 congeners, thereinafter briefly defined ‘‘toxic,’’ are generally determined.
