Method 8A

Determination of Sulfuric Acid Vapor or Mist and Sulfur Dioxide Emissions from Kraft Recovery Furnaces

This method is for the determination of sulfuric acid vapor or mist  from kraft recovery furnaces as an alternative to EPA Method 8.  Sulfates which are present in particulate matter and sulfur dioxide cause interferences with Method 8.  Samples are collected onto a filter and impinger solutions.  The sulfuric acid and sulfur dioxide are separated and both fractions are measured separately by the barium-thorin titration method.  It is also possible to determine filterable particulates by using a heated glass fiber filter for collection.

A modified Method 5 train consisting of a heated probe, heated quartz filter, heated SO2 condenser and series of impingers is used for collection.  The first two impingers are filled with 100mL of 3% hydrogen peroxide (H2O2) and the third impinger with 100mL of distilled deionized water.

After sample collection, the probe, filter holder and H2SO4 condenser are rinsed with deionized water and put into Container 1.  Container 2 consists contents of the first two impingers.  Note the liquid levels in both containers prior to shipping them to the lab.  Each container is analyzed separately.

Possible method interferences are fluorides, free ammonia, dimethyl aniline and recovery furnace salt cake.

US-EPA approved the use of Method 8A in December 1996 for the determination of acid vapor or mist and sulfur dioxide emissions from kraft recovery furnaces.

(40 CFR Part 60, Appendix A)


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Method Data

Hold Times, Preservatives, Preps, Collection, Analytical & Documentation
Holding Time:   None specified in the method.
Preservatives:   None specified in the method.
Required Preps:   Quartz filter
Collection Method:   Modified Method 5 train following Method 8A procedures.
Analytical Methodology:   Barium-thorin titration
Documentation:   8A

Analyte List*

Analyte Formula CAS Number Detection Limit
Sulfur dioxide
Sulfur trioxide
Sulfuric acid

* The analytes and detection limits listed for each method represent the typical detection limits and analytes reported for that particular method. Keep in mind that analyte lists may vary from laboratory to laboratory. Detection limits may also vary from lab to lab and are dependent upon the sample size, matrix, and any interferences that may be present in the sample.