GC Analysis of Sulfur Components in Propylene Using a Pulsed Flame Photometric Detector

Hydrogen sulfide (H2S), carbonyl sulfide (COS), and methyl mercaptan (CH3SH) are common components in light hydrocarbon streams. They have corrosive and toxic properties that can damage pipes and equipment. The emission of undesired odors caused by volatile sulfur compounds in intermediates and final products can have serious economic and environmental impact. In addition, the presence of sulfur can affect the performance of industrial processes, resulting in chemical reactions, loss of catalyst activity (catalyst poisoning), and ultimately lower yield.

These sulfur components must be quantified at low-ppb levels.1,2 They can be measured with sulfur-specific detection devices such as a pulsed flame photometric detector (PFPD), but large sample volumes are needed to reach the desired low-ppb detection limits. This creates matrix overload and quenching effects (decreased signal/sensitivity due to background interferences) on most sulfur-specific detectors, limiting the detector’s sensitivity and linearity and raising quantification limits. The Agilent J&W Select Low Sulfur porous layer open tubular (PLOT) column capillary (Agilent, Middelburg, The Netherlands) with novel stationary phase was developed for the analysis of sulfur species such as H2S, COS, and CH3SH in light hydrocarbon C3 matrices. The column has high loadability properties and unique selectivity, giving baseline resolution for sulfur components and matrix components.


The following was used—GC-PFPD column: Agilent J&W Select Low Sulfur, 60 m × 0.32 mm (p/n CP8575); oven: 65 °C isotherm; carrier gas: helium with a constant flow of 2.0 mL/min; injector: 200 °C, split 1:20; detector: PFPD, 200 °C; sample: propylene matrix containing ~500 ppb H2S, COS, and CH3SH; injection volume: 1 mL; injection: gas sampling valve.

Results and discussion

The stationary phase shows good selectivity between H2S, COS, and low mercaptans in various C3 hydrocarbon matrices. Therefore, coelution of the sulfur components and the matrix, which causes quenching, is avoided.

The system was equipped with a gas sampling valve.The gas sampling valve event table is shown in Table 1; the detector settings are shown in Table 2.

Figure 1 - Chromatogram of sulfur compounds H2S, COS, and CH3SH in a propylene matrix using the Agilent J&W Select Low Sulfur column with GC-PFPD.

The chromatogram of sulfur compounds H2S, COS, and CH3SH in a propylene matrix is illustrated in Figure 1. Methyl mercaptan shows peak broadening from column overloading due to the large amount of propylene. The propylene matrix elutes between COS and methyl mercaptan.


The Agilent J&W Select Low Sulfur column used in a GC with a sulfur-specific detector, such as a PFPD, can detect H2S, COS, and CH3SH at trace levels in a propylene matrix as a result of effective separation of the sulfur compounds and the matrix. Separating the matrix from the sulfur components eliminates the quenching effects caused by the matrix, and gives a better response for the sulfur compounds. The column provides a good response for reactive sulfur compounds, such as H2S, which makes detections of 20 ppb possible. Although this is a PLOT column, no spikes will be observed because the column does not shed particles. It can therefore be used safely in combination with valves.


  1. Wardencki, W. Review: Problems with the determination of environmental sulphur compounds by gas chromatography. J. Chromatogr. A 1998, 793, 1–19.
  2. Firor, R.L.; Quimby, B.D. Comparison of sulfur selective detectors for low-level analysis in gaseous streams. Agilent Technologies publ. 5988-2426EN.

    Ms. Jacobse is Research Engineer GC, Agilent Technologies, Herculesweg 8 4338 PL, Middelburg, The Netherlands; tel.: +31 118 671570; fax: +31 118 671569; e-mail: helena.jacobse@ agilent.com.