An automated method for the determination of sulfate.

An automated method of sulfate analysis is described, which can detect sulfate concentrations as low as 2.5 mug per ml water. The assay is based on the reaction of sodium rhodizonate and barium forming a colored complex. Sulfate quantitavely interferes with this reaction. The assay is reproducible in the range of 2.5 to 30 mug sulfate per ml water. This method conveniently and accurately measures water soluble sulfate filtered from the air, and is especially useful in assaying samples containing microgram quantities of sulfate from experimental inhalation apparatus.