ASTM D 4327 : 1997

1.1 This test method covers the sequential determination of fluoride, chloride, nitrite, ortho -phosphate, bromide, nitrate, and sulfate ions in water by chemically suppressed ion chromatography.

Note 1-Order of elution is dependent upon the column used; see Fig. 1.

1.2 This test method is applicable to drinking and waste waters. The ranges tested for this test method for each anion were as follows (measured in mg/L):

Fluoride 0.26 to 8.49 Chloride 0.78 to 26.0 Nitrite-N 0.36 to 12.0 Bromide 0.63 to 21.0 Nitrate-N 0.42 to 14.0 o-Phosphate 0.69 to 23.1 Sulfate 2.85 to 95.0

1.3 It is the user's responsibility to ensure the validity of this test method for other matrices.

1.4 Concentrations as low as 0.01 mg/L were determined depending upon the anions to be quantitated, in single laboratory work. Utilizing a 50-[mu]L sample volume loop and a sensitivity of 3 [mu]S/cm full scale, the approximate detection limits shown in Table 1 can be achieved. If lower detection levels are required, the sensitivity may be improved by using a lower scale setting (<3 [mu]S/cm) or a larger sample injection loop (>100 [mu]L). The analyst must assure optimum instrument performance to maintain a stable baseline at more sensitive conductivity full-scale settings.

1.5 The upper limit of this test method is dependent upon total anion concentration and may be determined experimentally as described in Annex A1. These limits may be extended by appropriate dilution or by use of a smaller injection volume.

1.6 Using alternate separator column and eluents may permit additional anions such as formate or citrate to be determined. This is not the subject of this test method.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.