Method 0051/9056A

Sampling and Analysis of Halogens and Halogen Acids from a Midget Impinger Emission Sampling Train

This method describes the collection and analysis of halogens and halogen acids in stack gas emission samples from hazardous waste incinerators and municipal waste combustors. This method is designed to collect anions in their gaseous forms. Use of this method is limited to the sampling of relatively dry, particulate-free gas streams. The collected samples are analyzed using Method 9056.

The method was written for the collection and analysis of HCl and Cl2 but has the potential for collection of all halogens and halogen acids, but has not yet been fully evaluated for that use.  This method is similar to EPA Methods 26 and 26A.

Samples are collected using a heated probe, Teflon filter and a series of midget impingers.   The 1st impinger (also called the Knockout iminger) is left empty,  the 2nd and 3rd impingers are filled with 15mL of 0.05M H2SO4 solution.  The 4th and 5th impingers are filled with 15mL of 0.1M NaOH.  A drying tube follows the impinger series.


After collection, the sampling train is weighed if a moisture determination is needed.  The contents of the Knockout impinger and two H2SO4 impingers are combined into one container along with the water rinses of the impingers.  The contents of the two NaOH impingers are combined into one container along with the water rinses of the impingers.  Each fraction of the train is analyzed separately.  Typically, the halogen acids (HCl, HBr, HF) are determined from the H2SO4 impingers and the halogens (Br2, Cl2) from the NaOH impingers.


(EPA SW-846)


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Method Data

Hold Times, Preservatives, Preps, Collection, Analytical & Documentation
Holding Time:   4 weeks from sampling to analysis
Preservatives:   Method 9056 specifies samples be kept at 4C. NaOH impingers preserved with 2mL 0.5M sodium thiosulfate in the field.
Required Preps:   Teflon mat filter
Collection Method:   Midget impinger sampling train following Method 0051 procedures.
Analytical Methodology:   Ion chromatography by SW-846 9056
Documentation:   0051

Analyte List*

Analyte Formula CAS Number Detection Limit
Hydrogen bromide
Hydrogen chloride
Hydrogen fluoride

* 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.