Sulfur Testing

Finding Total Percentage of Sulfur

Sulfur Analysis & Techniques

Midwest Microlab performs Sulfur analysis using the Schoniger Combustion Technique.

The solid sample is weighed into ashless paper and inserted into a custom made Platinum stopper. The stopper is fitted with a flask that is charged with the appropriate reactants and oxygen. On combustion the S present is oxidized from SO2 to SO3. The resulting liquid is then removed and titrated. With an indicator the color change is gold to pink. In cases with high levels of Fluorine, it is best to add Boric acid.

The most common standard for this determination is Cystine available through the NIST.  Other standards are used for specific circumstances.

Due to the exclusive use of the flask combustion in the Sulfur determination, we are not able to determine Sulfur on air-sensitive samples.

Interferences Associated with Sulfur Analysis:

Known Interference’s for Sulfur Analysis include Cu, Eu, F, I, Na, P, Se, and Sn. 

Phosphorus presence within the sample will produce low results

Please note the interferences above cannot be circumvented during analysis. Irregular results can be reported due to an interference within the molecular formula of the sample. Please note irregular results due to interferences cannot be interpreted by the chemists. Midwest Microlab chemists will perform requested analysis and report results as found with the understanding that the submitter understood the interferences associated and how it may affect results. Please indicate all elements or the molecular formula on the submission form. 

Suggested Sample Size according to Total Percentage Theory:

Theory %              Sulfur Single                  Sulfur Duplicate             Sulfur Triplicate

0-5 %                         30 mg                              60 mg                                  90 mg

5-20%                        25 mg                              50 mg                                  75 mg

 Above 20%               10 mg                              20 mg                                  30  mg

Standard Turnaround time for the total percentage of Sulfur results is within 3-4 business days. RUSH services are available for an additional fee per sample,per analysis with per single run. Rush results turnaround time for Sulfur analysis is within 2-3 business days. 

Midwest Microlab does NOT handle any samples containing Osmium, Uranium, or Thallium within the molecular formula.Midwest Microlab is able to perform samples with Depleted Uranium but must be clearly indicated on the submission form.  Please indicate on the comments section of the submission form if samples have a high toxicity or strong stench. We do not handle any Finished Pharmaceuticals for release or highly volatile liquid samples with boiling points of less than 40 deg C.