Method CARB 429

Determination of Polycyclic Aromatic Hydrocarbon (PAH) Emissions from Stationary Sources

This method applies to the determination of nineteen polycyclic aromatic hydrocarbons (PAHs) in emissions from stationary sources.  The method calls for use of isotope dilution LRMS (low resolution mass spectrometry) or HRMS (high resolution) for PAH determination.   Since the method was written, the HRMS analysis is typically the option of preference in order to achieve the lowest detection limits possible. 

Particulate and gaseous phase PAHs are extracted isokinetically from the stack and collected using a modified Method 5 sampling train consisting of a heated probe and filter holder, Teflon coated glass fiber filter, XAD-2 resin trap and a series of impingers. 

Particulate and gaseous phase PCDD,s PCDFs and PCBs are extracted isokinetically from the stack and collected using a modified Method 5 sampling train consisting of a heated probe and filter holder, glass fiber or quartz filter,  XAD-2 resin trap, and a series of impingers.  The first and second impingers are filled with 100mL of a 3mM sodium bicarbonate/2.4 sodium carbonate solution to neutralize any acids in the gas stream.  The third impinger is left empty and the fourth impinger is filled 200-300g of silica gel. 

After collection, the filter is placed in glass petri dish or bottle.  The method states to not wrap the filter in aluminum foil.  The probe, nozzle and front half of the filter holder (front half of sampling train) is rinsed with acetone, hexane and  methylene chloride (3x each) and placed in an amber glass jar.  The back half of the sampling train (back half of filter holder, transfer lines, connecting glassware) is rinsed with the same solvents and can be combined with the front half rinse.  The contents of each impinger are weighed and can be combined in a single amber glass container.  The impingers are rinsed with acetone, hexane and methylene chloride (3x each).  The rinse can be combined with the impinger contents.  The silica gel can be weighed in the field.

Upon return to the laboratory, the sample components are spiked and extracted with methylene chloride.  The method states that the impinger contents can be processed separately from the other components of the train if a breakthrough check is needed.  Typically, all components of the train are combined for analysis.