The mass selective detector is an ideal tool for the analysis of trace level volatile sulfur compounds. It provides structural information and achieves excellent sensitivity and selectivity in the Selected Ion Monitoring mode. This paper demonstrates the low parts-per-billion analysis of eight volatile sulfur compounds in various hydrocarbon matrices. The system is well suited for fuel cell developers to characterize fuel feedstocks and analyze impurities that can poison critical catalytic processes. Measurement of carbonyl sulfide in propylene is also demonstrated.
The document details an analytical method for determining volatile sulfur compounds (VSCs) at parts-per-billion levels. It highlights the suitability of the mass selective detector (MSD) for fuel cell developers needing to characterize feedstocks and monitor impurities that can poison catalytic processes in Polymer Electrolyte Membrane (PEMFC), Molten Carbonate (MCFC), Phosphoric Acid (PAFC), and Solid Oxide (SOFC) systems.
The specific hardware configuration reviewed involves the Agilent 6890N gas chromatograph coupled with a 5973N MSD. The text provides experimental details, including instrument conditions such as injection port temperature (150°C), column specifications (DB-1), and mass range settings. It demonstrates the system's capability to analyze eight specific sulfur compounds in matrices like helium, natural gas, propylene, and refinery gas using Selected Ion Monitoring (SIM) mode.
| Injection port temperature | 150°C |
|---|---|
| Split ratios | 1:1 upto 50:1 |
| Carrier gas flow mode | Constant flow mode 1.9 mL/min |
| Column dimensions and type | 60 m x 0.320 mm x 5.0 um DB-1 |
| Initial temperature and time | 40°C for 5 min |
| Temperature ramp rate | 25 °C/min |
| Final temperature and time | 270°C for 2 min |
| MSD Mass range | 33 to 100 and 12 to 100 |
| Source temperature | 230°C |
| Transfer line temperature | 280 °C |
The system analyzes eight volatile sulfur compounds: hydrogen sulfide, carbonyl sulfide, methyl mercaptan, ethyl mercaptan, dimethyl sulfide, carbon disulfide, t-butyl mercaptan, and tetrahydrothiophene.
The method was demonstrated in helium, natural gas, propylene, and refinery gas.
The use of the MSD with selected ion monitoring (SIM) can largely overcome the coelution problem caused by interfering hydrocarbons.
The calibration was focused in the ppb range, specifically from 88 to 1170 ppb for hydrogen sulfide in natural gas.