TRS MEDOR® — Chromatotec Sulfur Compounds Analyser

The TRS MEDOR is an automatic, isothermal gas chromatograph built by Chromatotec for continuous measurement of hydrogen sulfide, mercaptans and sulphides — the compound group generally referred to as total reduced sulfur, or TRS. It is available in two versions: a ppm-range instrument and a ppb-range instrument, covering applications from trace-level odour monitoring to higher-concentration process streams.

What it measures

In its standard configuration, the analyser resolves H₂S, SO₂, dimethyl sulfide (DMS), methyl mercaptan (MM) and ethyl mercaptan (EM) within a 600-second cycle. For applications that require a wider compound list, Chromatotec offers an extended configuration adding DMDS, DES, IPM, TBM, NPM, 2BM, IBM, NBM, MES and THT, at a cycle time of 1200 seconds. The instrument also calculates Odor Index, Total Sulfur and Total Mercaptans directly from the chromatographic result — useful where a single composite value is needed for reporting or process control, rather than reading each compound separately.

Detection performance

• Detection limit (H₂S, SO₂, DMS, MM, EM): LDL ≤ 0.1 ppm
• Detection limit (DMS, standard): ≤ 1.5 ppb(v)
• Detection range: 0–10, 0–100 or 0–1000 (ppb or ppm, depending on version)
• Linearity: 0.995 for all compounds
• Repeatability (RSD, concentration): < 3% over 48 hours
• Repeatability (RSD, retention time): < 0.5% over 48 hours
• Cycle time (standard compound list): 600 seconds
• Cycle time (extended compound list): 1200 seconds

The two-tier cycle time is worth noting when specifying the instrument: the standard five-compound method reports every 10 minutes, while the extended method — needed where regulatory or process requirements call for the wider sulfur speciation — doubles that to 20 minutes. Not specified by the manufacturer: detector technology used to achieve these limits.

Gas supply requirements

• Carrier gas: dry air or N₂ at 3 bar, ≤ 4 ml/min
• Calibration gas (continuous): ~50 ml/min
• Calibration gas (during validation, M52 configuration): ~250 ml/min
• Pneumatic valve: 90 ml per commutation

These figures matter for anyone sizing gas cylinders or a generator/zero-air supply around the instrument — particularly the higher flow demand during validation cycles, which is easy to underestimate if only the continuous calibration figure is used for sizing.

Control, data and connectivity

The TRS MEDOR runs on an embedded Windows-based computer with its own LCD display, storing results locally on 128 GB of SSD memory. Ethernet connectivity supports remote control, which matters for installations where the analyser sits in a shelter or enclosure some distance from the control room. Beyond Ethernet, no further communication protocols (Modbus, 4–20 mA, etc.) are stated on the manufacturer's page — confirm against the TSP TRS MEDOR datasheet if this is a specification requirement.

Standards and regulatory reference

• ISO 19739:2004
• DIN 51855/7
• ASTM D7493-22
• ASTM D7165-22
• EPA Method 16B — Total Reduced Sulfur, Gas Chromatograph Analysis

These are reference measurement standards and methods that the TRS MEDOR's technique is aligned with, rather than certifications held by the instrument itself. Where a tender specifically requires compliance to one of these methods, this should be confirmed against the relevant datasheet rather than assumed from the product page alone.

Explosion-protected variants

Chromatotec also publishes technical documentation for Exd, Exp and CSA-certified versions of the underlying GC 866 platform, indicating that hazardous-area variants of this analyser exist. Zone classification and specific ATEX/CSA ratings are not detailed on the product page itself and should be confirmed before quoting a hazardous-area installation.

Configuration

• Required: carrier gas supply (dry air or N₂), calibration gas supply
• Application-dependent: extended compound-list configuration (1200s cycle), explosion-protected enclosure (Exd/Exp/CSA)
• Not specified: sample conditioning, probes, or sampling system requirements — these will depend on the sample matrix and should be discussed with AAVOS during specification

Why AAVOS

AAVOS distributes Chromatotec instruments in Belgium, the Netherlands and Luxembourg, and can support product selection, system configuration, installation, calibration and ongoing maintenance for the TRS MEDOR. Where a project involves an explosion-protected variant or an extended compound list, AAVOS can help confirm the correct configuration against your application before ordering.

Get in touch

Contact AAVOS for technical advice, configuration support or a quotation on the TRS MEDOR.

06 — FAQ

What does the TRS MEDOR measure?

In its standard configuration it measures H₂S, SO₂, dimethyl sulfide, methyl mercaptan and ethyl mercaptan, and calculates Odor Index, Total Sulfur and Total Mercaptans from the result. An extended configuration adds further sulfur compounds at a longer cycle time.

What is the difference between the ppm and ppb versions?

Both versions use the same measurement principle; they differ in their detection range, covering either 0–10/0–100 ppb or 0–1000 ppb/ppm-level ranges depending on which is selected. Chromatotec also offers more sensitive configurations on request for specialised applications.

How long is a measurement cycle?

600 seconds for the standard five-to-seven compound list, or 1200 seconds when the extended compound list is used.

Which standards or methods does the TRS MEDOR reference?

ISO 19739:2004, DIN 51855/7, ASTM D7493-22, ASTM D7165-22, and EPA Method 16B for total reduced sulfur determination.

Is the TRS MEDOR certified for hazardous areas?

Explosion-protected (Exd, Exp) and CSA-certified variants of the underlying GC 866 platform exist. Specific zone ratings should be confirmed with AAVOS for your installation before ordering.

What gas supply does the instrument need?

Dry air or nitrogen as carrier gas at 3 bar (≤ 4 ml/min), plus a calibration gas supply of roughly 50 ml/min continuously, rising to around 250 ml/min during validation cycles on the M52 configuration.

How is data stored and accessed?

The instrument runs on an embedded Windows-based computer with a local LCD display and 128 GB of SSD storage, with Ethernet connectivity for remote control.

Can AAVOS help specify the right configuration?

Yes. AAVOS can advise on compound list, cycle time, gas supply sizing, and whether an explosion-protected variant is needed for your application.