This method is for the determination of sulfides in aqueous, solid waste materials, or effluents. This method provides only a semi-quantitative determination of sulfide compounds considered "acid-insoluble" (e.g., copper sulfide and tin(IV) sulfide) in solid samples. Recoveries have been shown to be 20 to 40% for copper sulfide, one of the most stable and insoluble compounds, and 40 to 60% for tin (IV) sulfide which is slightly more soluble.
For acid-soluble sulfide samples, separation of sulfide from the sample matrix is accomplished by the addition of sulfuric acid to the sample. The sample is heated to 70°C and the hydrogen sulfide which is formed is distilled under acidic conditions and carried by a nitrogen stream into zinc acetate gas scrubbing bottles where it is precipitated as zinc sulfide.
For acid-insoluble sulfide samples, separation of sulfide from the sample matrix is accomplished by suspending the sample in concentrated hydrochloric acid by vigorous agitation. Tin(II) chloride is present to prevent oxidation of sulfide to sulfur by the metal ion (as in copper(II)), by the matrix, or by dissolved oxygen in the reagents. The prepared sample is distilled under acidic conditions at 100°C under a stream of nitrogen. Hydrogen sulfide gas is released from the sample and collected in gas scrubbing bottles containing zinc(II) and a strong acetate buffer. Zinc sulfide precipitates.
This method is suitable for measuring sulfide concentrations in samples which contain between 0.2 and 50 mg/kg of sulfide.
No Obligation Quotation for Analytical Services
If you would like us to provide a quote for laboratory analysis, just provide us with as much information as you can about your project (the more, the better) and we'll provide you a quote via email. As you are searching or browsing our Analytical Guide, you'll see the Request-A-Quote icon... just click on it to start the request process.
| Hold Times, Preservatives, Preps, Collection, Analytical & Documentation | |
|---|---|
| Holding Time: | 7 days from sample collection to preparation if properly preserved. Cool samples and store at 4°C with no headspace. |
| Preservatives: | Add 4 drops of 2N zinc acetate per 100 mL of sample and adjust pH to > 9 with 6N NaOH. |
| Required Preps: | 250mL Plastic bottle with Teflon-lined lid |
| Collection Method: | Grab sampling |
| Analytical Methodology: | Distillation |
| Documentation: | 
9030B
|
| Analyte | Formula | CAS Number | Detection Limit | |
|---|---|---|---|---|
| Sulfide | S(-2) |
18496-25-8 |
0.4 |
mg/L |
* The analytes and detection limits listed for each method represent the typical detection limits and analytes reported for that particular method. Keep in mind that analyte lists may vary from laboratory to laboratory. Detection limits may also vary from lab to lab and are dependent upon the sample size, matrix, and any interferences that may be present in the sample.