World-renowned multi-gas analyzers and custom spectroscopy solutions

Who We Are

Cerex designs and manufactures FTIR and UV-DOAS multi-gas analyzers to solve complex monitoring challenges

For over 20 years, Cerex has used solid spectroscopy techniques to simultaneously monitor multiple gases in real time. Our analyzers are used for Fenceline Monitoring, Continuous Emission Monitoring, Process Monitoring, Ambient Air Quality Monitoring, Indoor Air Quality Monitoring, Leak Detection, Hazmat First Response, and more

Real-time measurements, instant data

Cerex’s unique, proprietary software uses algorithms to display target gas readings every 5-30 seconds – resulting in accuracy that is unmatched in the market.
Cerex analyzers save raw spectrographic information, allowing further analysis after the fact. Our clients can see what compounds are in the air at any given time – an advantage compared to “black box solutions”.

Low maintenance

Unlike competing products, Cerex’s equipment uses little to no moving parts that wear out. Combined with inherent calibration (preventing time-consuming troubleshooting), and integrated networking, our products provide peace of mind and low cost of ownership. Our devices, such as the UV Sentry HC, are highly sensitive, precise, and reliable in rough field conditions.

Built for regulation compliance

Designed from the ground up, our analyzers are specifically engineered to meet regulations, including the HON (Hazardous Organic NESHAP) rule, US EPA criteria for fence-line and refinery benzene monitoring, and more.

UV Sentry HC (Harsh Climate Model)
UV DOAS Analyzer

How does Cerex equipment operate?

Cerex equipment can reliably detect hundreds of gases

Our acclaimed equipment couples UV DOAS or FTIR technology with ultra low minimum detection limits (down to parts per trillion)


Ultra Violet Differential Optical Absorption Spectroscopy

Benzene / BTEX


Sulfur Dioxide SO2

Nitric Oxide NO

Nitrogen OXideNO2



…and more


Fourier-Transform Infrared Spectroscopy

Sulfur Dioxide (SO2)
Nitrogen Oxide (NO)
Nitric Oxide (NO2)
Carbon Oxide (CO)
Carbon Dioxide (CO2)
Methane (CH4)
Hydrochloric Acid (HCL)
Water Vapor

…and more

UV-DOAS or FTIR Technology

Cerex offers both UV-DOAS and FTIR technology based analyzers to target your gases of interest at the lowest detection limits possible. Depending on your application, there are pros and cons to each option.

Generally, UV-DOAS based analyzers are the most cost-effective choice for focusing on select gases with extreme sensitivity. In contrast, FTIR based analyzers are highly adept at monitoring dozens of gases simultaneously – with laboratory sensitive quality.

Not sure what best suits your project? Our application engineers would be happy to discuss your specific application with you.


Fenceline Monitoring and Regulation Compliance

Cerex Fenceline Analyzers are designed to meet existing and emerging regulatory requirements for industrial facilities worldwide – offering high sensitivity, gapless fence-line coverage, and cost effective long term operation

  • HON Rule for Benzene, 1,3-Butadiene, Chloroprene, Ethylene Dichloride, Vinyl Chloride
  • 40 CFR § 63.658 / USEPA Method 325 A/B
  • SCAQMD Rule 1180
  • BAAQMD Refinery Regulation 12 Rule 15
  • USEPA TO-16
  • RCER-2020

Portable Gas Analyzers
(Indoor Monitoring and more)

Cerex portable analyzers include the Shepherd FTIR, Cerex FTIR and Hound series UVDOAS instruments designed for efficient multi-gas monitoring of common and uncommon air toxics and health hazards

  • Waste Anesthetics
  • Hospital Monitoring
  • Odor complaint Response
  • HAZMAT response
  • Industrial Hygiene
  • Leak Detection
  • Chemical Warfare Agents (CWAs)
  • Toxic Industrial Chemicals (TICs)
  • Can be used to meet HON Rule and other EPA criteria

Continuous Emissions Monitoring (CEMs)

Cerex specializes in both Traditional Method 320, 321, and 318 compliant extractive CEMs as well as insitu CEM and process control analyzers for a diverse array of applications and target gas mixtures

  • Traditional extractive systems
  • Insitu non-contact Cross Stack and parallel sample stream
  • Process Control
  • UVDOAS / FTIR Hybrid systems
  • Turn-key complete hardware systems
  • DeSOx
  • DeNOx
  • Ammonia Slip
  • Criteria Gas
  • VOCs

Other Challenges and Custom Built Solutions

For any application, we can customize a solution for you with our extensive list of options. Talk to our application engineers about any unique needs you may have

Serving a Wide Variety of Industries

Cerex has an extensive client base including government agencies, major oil refineries, major chemical manufacturers, and international environmental consultants. We offer in-depth training on the spectroscopy techniques we employ in our instruments, as well as detailed support of all hardware and software.

  • Petroleum / Oil Refineries

  • Governmental Agencies

  • Mass Livestock Farms

  • Nuclear Facilities

  • Solar

  • Chemical Manufacturing

  • Steel Manufacturing

  • Synthetic Rubber Plants

  • Power Generation Plants

  • ..and more
Petroleum Refineries
Synthetic Rubber Plants
Tank Farms
Wastewater Treatment


Our Solutions in Action

Cerex proudly partners with Sonoma Technologies (STI) to implement monitoring solutions all over the world.

  • Trusted by some of the world’s largest petrochemical companies (including Chevron, Shell, Marathon, and more)

  • Analyzers provided to and used by multiple government and regulatory bodies (including the EPA)

Click below to view some of our current live installations for major petrochemical companies in North America

Current open-path solution for a refinery in California

Talk to our application specialists about your unique needs

Our engineers have decades of experience in creating custom solutions to meet your monitoring challenges.
Contact us today to explore solutions for your air or process monitoring project.