Determination of Metals Emissions from Stationary Sources – USEPA Method 29

USEPA Method 29 is used for the determination of metals emissions from stationary sources.  This method may also be used to determine particulate emissions in addition to the metals emissions. 
 
The method is used to determine the following analytes:

• antimony (Sb)
• arsenic (As)
• barium (Ba)
• beryllium (Be)
• cadmium (Cd)
• chromium (Cr)
• cobalt (Co)
• copper (Cu)
• lead (Pb)
• manganese (Mn)
• mercury (Hg)
• nickel (Ni)
• phosphorus (P)
• selenium (Se)
• silver (Ag)
• thallium (Tl)
• zinc (Zn)

A stack sample is withdrawn isokinetically from the source, particulate emissions are collected in the probe and on a heated filter, and gaseous emissions are then collected in an aqueous acidic solution of hydrogen peroxide (analyzed for all metals including Hg) and an aqueous acidic solution of potassium permanganate (analyzed only for Hg).
 
The recovered samples are digested, and appropriate fractions are analyzed for Hg by cold vapor atomic absorption spectroscopy (CVAAS) and for Sb, As, Ba, Be, Cd, Cr, Co, Cu, Pb, Mn, Ni, P, Se, Ag, Tl, and Zn by inductively coupled argon plasma emission spectroscopy (ICAP) or atomic absorption spectroscopy (AAS).  Graphite furnace atomic absorption spectroscopy (GFAAS) is used for analysis of Sb, As, Cd, Co, Pb, Se, and Tl if these elements require greater analytical sensitivity than what is obtained by ICAP.  If one so chooses, AAS is used for analysis of all listed metals if the resulting in-stack method detection limits meet the goal of the testing program.  Similarly, inductively coupled plasma-mass spectroscopy (ICP-MS) may be used for analysis of Sb, As, Ba, Be, Cd, Cr, Co, Cu, Pb, Mn, Ni, Ag, Tl and Zn.
 
Iron (Fe) is a spectral interference during the analysis of As, Cr, and Cd by ICAP.  Aluminum (Al) is a spectral interference during the analysis of As and Pb by ICAP.  Generally, these interferences are reduced by diluting the analytical sample, but such dilution raises the in-stack detection limits.  Background and overlap corrections are used to adjust for spectral interferences.