MONITORING AND LABORATORY DIVISION
STANDARD OPERATING PROCEDURE

S.O.P. No. MLD 007 - Determination of Sulfate, Nitrate, and Chloride
                                      Using Ion Chromatography

SCOPE

This document describes a procedure for quantifying atmospheric concentrations of sulfate, nitrate, and chloride anions.  The procedure is based on the analysis of suspended particulate matter collected on a filter medium with a size selective inlet (SSI) high-volume sampler.

SUMMARY OF METHOD

Atmospheric suspended particulate matter is collected over a 24-hour period on a (8x10 inch) quartz fiber filter.  The filter is aspirated with a size selective inlet high-volume sampler.  A quarter of the filter is extracted in deionized water, filtered and injected into an ion exchange chromatographic column.  After separation, the anions pass through an electronic suppressor to eliminate background conductivity and are then detected with a conductivity cell.  The resultant peaks are identified by their characteristic retention times and quantified by reference to external standards.