Method 16
Semicontinuous Determination of Sulfur Emissions From Stationary Sources
40 CFR Part 60, Appendix A-6
From the method — regulatory text
Sections 1.0 and 2.0 of Method 16—Semicontinuous Determination of Sulfur Emissions From Stationary Sources, as published at 40 CFR Part 60, Appendix A-6. Retrieved 10/07/2026. The full method is on the eCFR.
1.0 Scope and Application
1.1 Analytes.
| Analyte | CAS No. | Sensitivity |
|---|---|---|
| Dimethyl disulfide [(CH3)2 S2] | 62-49-20 | 50 ppb. |
| Dimethyl sulfide [(CH3)2 S] | 75-18-3 | 50 ppb. |
| Hydrogen sulfide [H2 S] | 7783-06-4 | 50 ppb. |
| Methyl mercaptan [CH4 S] | 74-93-1 | 50 ppb. |
1.2 Applicability. This method is applicable for the determination of total reduced sulfur (TRS) compounds from recovery furnaces, lime kilns, and smelt dissolving tanks at kraft pulp mills and fuel gas combustion devices at petroleum refineries.
Note:
The method described below uses the principle of gas chromatographic (GC) separation and flame photometric detection (FPD). Since there are many systems or sets of operating conditions that represent useable methods of determining sulfur emissions, all systems which employ this principle, but differ only in details of equipment and operation, may be used as alternative methods, provided that the calibration precision and sample line loss criteria are met.
1.3 Data Quality Objectives. Adherence to the requirements of this method will enhance the quality of the data obtained from air pollutant sampling methods.
2.0 Summary of Method
2.1 A gas sample is extracted from the emission source and an aliquot is analyzed for hydrogen sulfide (H2S), methyl mercaptan (MeSH), dimethyl sulfide (DMS), and dimethyl disulfide (DMDS) by GC/FPD. These four compounds are known collectively as TRS.
EssentialRegs notes
Our plain-English reading of Method 16. Not the method text.
What it measures
The concentrations of individual reduced sulfur compounds in an exhaust gas, including hydrogen sulfide, methyl mercaptan, dimethyl sulfide and dimethyl disulfide, measured at repeated intervals.
How it works
A sample of the gas is drawn from the source and injected into a gas chromatograph at regular intervals. The chromatograph separates the sulfur compounds and a flame photometric detector, which responds to sulfur, measures each one. Because the analysis repeats during the test, the result is a series of readings rather than a single collected sample.
Equipment
A gas chromatograph with a flame photometric detector, a sampling probe and line, a sample conditioning and dilution system, and sulfur calibration standards.
When a rule cites it
Tests where the individual reduced sulfur compounds in an exhaust must be identified and added up to a total reduced sulfur figure. It is the chromatographic alternative to the impinger-based Method 16A.
Notes for compliance staff
Method 16 and Method 16A both address reduced sulfur but by different means: Method 16 is instrumental and reports compounds individually, while Method 16A is wet chemistry and reports one combined total. A rule's citation of one method does not allow the other unless the rule says so.
Cited by
Provisions in the corpus whose text cites Method 16. Subscribers land on the provision in the regulation reader; visitors see a preview of it (the GP05 sample opens in full).
40 CFR Part 60 Subpart OOOO
- § 60.5430 — What definitions apply to this subpart?
40 CFR Part 60 Subpart OOOOa
- § 60.5430a — What definitions apply to this subpart?
40 CFR Part 60 Subpart OOOOb
- § 60.5430b — What definitions apply to this subpart?
40 CFR Part 60 Subpart OOOOc
- § 60.5430c — What definitions apply to this subpart?
The sections marked as regulatory text above are reproduced from the CFR. Everything under ‘EssentialRegs notes’ is our reference copy, not the method. The method as published in the CFR controls.