Semivolatile Organic Compounds, Dioxins and Furans from Stationary Sources
This is a modified method to allow for simultaneous sampling and analysis for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and semi-volatile organic compounds (SVOCs) from stationary sources. This is often commonly referred to in the industry as a joint train because two sampling methods are combined in order to save costs when sampling from the same source at the same conditions. SVOCs are loosely defined as those compounds with a boiling point greater than 100 °C. The PCDDs/PCDFs determined are seventeen 2,3,7,8-substituted isomers considered to be the most toxic. Total PCDDs/PCDFs by congener group (e.g. Total TCDD, PeCDD) are also reported.
Samples are collected isokinetically using a modified Method 5 train which consists of a glass fiber filter containing no organic binders, XAD-2 resin trap, and a series of impingers. The sampling train is rinsed with acetone and/or methylene chloride followed by toluene. Acetone and methylene chloride rinses can be combined but the toluene rinses need to be kept separately. The rinses and impinger water are collected and sent to the laboratory for analysis. Note that the impinger water is extracted and analyzed for SVOCs.
Typically all components of the train, including the rinses, are extracted and combined to produce one extract for analysis which represents the entire sampling train. This extract is then split and 50% of the extract is archived in case there are problems and re-analysis is necessary. PCDDs/PCDFs undergo an extensive cleanup prior to analysis which is not necessary for SVOCs. If there are problems with the cleanup, the archived portion of the sample extract can be processed avoiding the need to resample. The splitting of the extract will not affect the PCDD/PCDF detection limits because they are quantitated using isotopically labeled internal standards. However, SVOC detection limits from a joint train will be elevated due to the extract split.
Method 0023A is a sampling method for PCDDs/PCDFs similar to 23. The major difference is that 0023A requires that the front half of the train consisting of the rinses (nozzle, probe, front half filter holder) and filter are extracted and analyzed separately from the back half of the train consisting of the rinses (back half filter holder, condenser coil) and XAD-2 resin.