--- title: "AMETEK Brookfield Jerome Specialty Air Analyzers | Aethair" description: "AMETEK Brookfield Jerome 631-X and 431-X gold-film analyzers for hydrogen sulfide and mercury vapor, in the Aethair sensor catalog via Thiamis." url: https://aethair.io/sensors/ametek-brookfield-specialty-air-analyzers/ --- Sensors · Specialty Air Analyzers # AMETEK Brookfield Jerome Specialty Air Analyzers Jerome portable single-gas analyzers by AMETEK Brookfield (formerly AMETEK Arizona Instrument). The 631-X measures hydrogen sulfide (0.003–50 ppm) and the 431-X measures mercury vapor (0.003–0.999 mg/m³), both with a proprietary gold-film sensor and an RS-232 serial port. The 631-X remains a current product; the 431-X has been superseded by the newer USB-based J405. [Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Build a Configuration](https://aethair.io/build/?params=h2s,hg) At a glance **2** parameters **2** models [**Connects via Thiamis** RS-232 · ASCII](https://aethair.io/products/thiamis/) 4 standards limit what it measures - [Cal/OSHA PEL Cal/OSHA Permissible Exposure Limits (8 CCR §5155, Table AC-1)](https://aethair.io/standards/cal_osha_pel/) - [NIOSH REL NIOSH Recommended Exposure Limits (RELs)](https://aethair.io/standards/niosh_rel/) - [OSHA construction OSHA Construction Exposure Limits (29 CFR 1926.55)](https://aethair.io/standards/osha_construction_pel/) - [OSHA PEL OSHA Permissible Exposure Limits (PEL)](https://aethair.io/resources/osha-air-quality-standards-compliance/) Measures ## What the AMETEK Brookfield Jerome Measures 2 parameters, each linked to its page: the sensors, units, and standards behind it. [Hydrogen Sulfide (H₂S) ppm](https://aethair.io/parameters/h2s/) [Mercury (Hg) mg/m³](https://aethair.io/parameters/hg/) [Connects via **Thiamis**](https://aethair.io/products/thiamis/) Wired interface [RS-232 ASCII](https://aethair.io/products/thiamis/#port-rs232) Models ## AMETEK Brookfield Jerome Models 2 models, each with what it measures and the ranges its datasheet gives. | Model | Description | Measures & specs | | - | - | - | | **Jerome-631X** | Hydrogen sulfide analyzer. Proprietary gold-film sensor, 0.003–50 ppm H2S at 0.001 ppm resolution; optional ammonia and chlorine inlet filters remove those interferents. Standard RS-232 serial port plus a 4–20 mA current loop. Current product. | [Hydrogen Sulfide (H₂S)](https://aethair.io/parameters/h2s/) | | **Jerome-431X** | Mercury vapor analyzer. Gold-film sensor, 0.003–0.999 mg/m³ Hg at 0.001 mg/m³ resolution, \~12 s sample readings; RS-232 serial output at 1200 baud. Superseded by the newer USB-based J405/J505 (end of repair service) but still integrated over RS-232. | [Mercury (Hg)](https://aethair.io/parameters/hg/) | Standards ## Standards for What It Measures Standards that set limits on the parameters it reports. [Cal/OSHA PEL Cal/OSHA Permissible Exposure Limits (8 CCR §5155, Table AC-1) 2 of its parameters](https://aethair.io/standards/cal_osha_pel/) [NIOSH REL NIOSH Recommended Exposure Limits (RELs) 2 of its parameters](https://aethair.io/standards/niosh_rel/) [OSHA construction OSHA Construction Exposure Limits (29 CFR 1926.55) 2 of its parameters](https://aethair.io/standards/osha_construction_pel/) [OSHA PEL OSHA Permissible Exposure Limits (PEL) 2 of its parameters](https://aethair.io/resources/osha-air-quality-standards-compliance/) [ACGIH TLV ACGIH Threshold Limit Values (TLV) 1 of its parameters](https://aethair.io/standards/acgih_tlv/) [OSHA confined space Confined-Space Atmospheric Limits 1 of its parameters](https://aethair.io/standards/confined_space/) [SCAQMD 1180 SCAQMD Rule 1180: refinery fenceline and community air monitoring 1 of its parameters](https://aethair.io/standards/scaqmd_1180/) Guidance that relies on it [BAAQMD Regulation 12, Rule 15: petroleum refining emissions tracking](https://aethair.io/standards/baaqmd_12_15/) On the platform ## What the AMETEK Brookfield Jerome Gets From Aethair Connected through Thiamis, its readings arrive in the same Environet account as Aethair's own monitors. ### [Live data and alerts](https://aethair.io/platform/environet/) [Environet](https://aethair.io/platform/environet/) shows the instrument live and alerts the people you choose by email, SMS, and webhook, at the thresholds you set. [Noesis](https://aethair.io/platform/noesis/) sets up a dashboard, a report, or an alert from a plain-text request. ### [Compliance reports](https://aethair.io/platform/reports/) [Aethair Reports](https://aethair.io/platform/reports/) produces scheduled or on-demand reports from the instrument's readings, as a PDF or secure link. Templates cover Aethair Blue, WELL v2, cabin air (ISO 23875), and the CMS-2567 healthcare codebook (ASHRAE 170), or you can report against custom limits such as OSHA PELs, NAAQS, EPA guidance, or your own program limits. ### [Dashboards and the app](https://aethair.io/platform/dashboards/) Environet dashboards and the [Aethair App](https://aethair.io/platform/app/) show the instrument's readings just like any Aethair device. The occupant-facing [Aethair Dashboards](https://aethair.io/platform/dashboards/) status display is built around Aethair IAQ and Aethair PRO. Similar ## Other Specialty Air Analyzers ### [2B Technologies](https://aethair.io/sensors/2b-technologies-specialty-air-analyzers/) [Specialty Air Analyzers](https://aethair.io/sensors/2b-technologies-specialty-air-analyzers/) [The 2B Technologies POM is a personal ozone monitor that measures ozone by UV absorption (254 nm)…](https://aethair.io/sensors/2b-technologies-specialty-air-analyzers/) ### [AethLabs](https://aethair.io/sensors/aethlabs-specialty-air-analyzers/) [Specialty Air Analyzers](https://aethair.io/sensors/aethlabs-specialty-air-analyzers/) [AethLabs microAeth MA-series aethalometers (the wearable MA200, portable MA350, and rack-mount…](https://aethair.io/sensors/aethlabs-specialty-air-analyzers/) ### [Defiant Technologies](https://aethair.io/sensors/defiant-technologies-specialty-air-analyzers/) [Specialty Air Analyzers](https://aethair.io/sensors/defiant-technologies-specialty-air-analyzers/) [Defiant Technologies FROG portable gas chromatograph (GC-PID). A MEMS micro-preconcentrator,…](https://aethair.io/sensors/defiant-technologies-specialty-air-analyzers/) ### [Durridge](https://aethair.io/sensors/durridge-specialty-air-analyzers/) [Specialty Air Analyzers](https://aethair.io/sensors/durridge-specialty-air-analyzers/) [The DURRIDGE RAD7 is a continuous radon/thoron monitor. It collects alpha emitters…](https://aethair.io/sensors/durridge-specialty-air-analyzers/) Questions ## AMETEK Brookfield Jerome FAQ How does a Jerome analyzer measure its target gas? Both models use a proprietary gold-film sensor. An internal pump draws a fixed volume of ambient air across a thin gold film; hydrogen sulfide (631-X) or mercury vapor (431-X) adsorbs onto the film and raises its electrical resistance in proportion to the mass collected, which the instrument converts to a concentration. The film is regenerated between samples, and the sensing principle has been in field use for over 35 years. Does one driver cover both analyzers, and how does it read them? Yes. A single driver serves both analyzers over their RS-232 serial port (1200 baud, 8 data bits, no parity). It first polls the instrument for its measurement unit: a reading in ppm identifies the 631-X and is recorded as hydrogen sulfide, while a reading in mg/m³ identifies the 431-X and is recorded as mercury. It then reads the displayed concentration each interval. Does this driver cover the newer Jerome J605 and J405? No, only the RS-232 631-X and 431-X, which answer a live poll for their current reading. The newer USB-based J605 (hydrogen sulfide) and J405/J505 (mercury) do not support unattended operation. Their USB port only sends the stored data log when an operator presses 'Send to PC' on the instrument, so a remote logger cannot poll them. Their only continuous machine output is a 4-20 mA analog signal. The 631-X remains a current AMETEK Brookfield product; the 431-X is superseded by the J405 but stays integrated over RS-232. Is the 631-X selective for hydrogen sulfide? The gold-film sensor responds specifically to hydrogen sulfide rather than to common background gases. For environments with known interferents, AMETEK offers optional inlet filters (an ammonia filter and a chlorine filter) that remove those gases before the sample reaches the sensor. Sources: [www.brookfieldengineering.com](https://www.brookfieldengineering.com/products/toxic-gas-analyzers/hydrogen-sulfide-analyzers/jerome-631-x) · [www.brookfieldengineering.com](https://www.brookfieldengineering.com/-/media/ametekbrookfield/product-manuals/jerome-431-mercury-analyzer-operation-manual-700-0046.pdf)