The procedures after the extraction from the aerosol filter
(Section 3.6.2) for Dionex systems and for Waters systems are described in
Section 4.1.
This method is applicable for the determination of water-soluble particulate sulphate collected on a filter. The working range is within 1 to 80 µg S per filter.
Particulate sulphate collected on a filter is dissolved in water. The concentration of sulphate in the solution is determined spectrophotometrically as described in Section 4.2.1 or 4.2.2.
Same as listed in Section 4.2.1. In addition: 50 ml Erlenmeyer flasks.
Same as listed in Section 4.2.1.
Same as listed in Section 4.2.1.
Proceed as described in Section 4.2.1.
Transfer the exposed filters and blank filters to 50 ml Erlenmeyer flasks. Add 20 ml of water, shake well and leave for 30 minutes. (For small filters and low concentrations of sulphate use only 10 ml of water). Proceed according to Section 4.2.1.7 or 4.2.2.6.
The concentration of water soluble particulate sulphate in the air sample expressed in micrograms of sulphur per cubic metre, is given by:
a = concentration
of sulphur, in milligrams per litre, read from the calibration curve.
b = concentration
of sulphur in the blank sample
v1 = the
volume of water, in litres, used to extract the filter.