Sulfide ion is found in ground waters and wastewater, causing odor and corrosion problems. If acidified, these waters can release hydrogen sulfide, which is extremely toxic even at low levels. This test method provides a means for interference-free measurement of free sulfide ion.

Note 1—Sulfide forms complexes with hydrogen ions (HS ¹⁻ and H₂S). In addition, sulfide ion forms soluble complexes with elemental sulfur (S₂ ²⁻, S₃ ²⁻, S₄ ²⁻, etc.), tin, antimony, and arsenic ions.

1.1 This test method uses an ion-selective electrode to determine sulfide ion in water. The test method is applicable in the range from 0.04 to 4000 mg/L of sulfide.

1.2 Precision data presented in this test method were obtained using reagent water only. It is the user's responsibility to ensure the validity of this test method for untested types of water.

1.3 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. Sulfide samples, when acidified, can release highly toxic hydrogen sulfide gas. For a specific precautionary statement, see Note 2.