The DF-749 moisture analyzer checks purity in UHP gases

Using Servomex’s Tunable Diode Laser (TDL) sensor the DF-749 provides trace/ultra-trace moisture measurements for checks of ultra-high-purity (UHP) electronic gases in a range of background gases.

  • High-stability TDL measurements
  • A no-compromise solution
  • Simple maintenance and reduced ongoing costs

Ready to buy? Here’s how it works

It’s easy to find the product you need for your application with Servomex.


Get in touch to tell us what you need and the application you plan to use it for


Our expert team will help you select the right product package, ensuring you have the accessories and support to get the best performance from your analyzer


Your analyzer will be assembled in one of our state-of-the-art engineering centers and rapidly dispatched to your site

Ideal for quality checks of UHP gases

Joseph Ha
Product Manager, Purity & Speciality

The DF-749 provides trace and ultra-trace moisture contaminant measurements in a variety of background gases, including nitrogen, hydrogen, helium, argon and oxygen.

Ideal for quality checking of UHP gases used in LCD and LED manufacture, the DF-749’s compact form makes it easily portable for easy cart or mobile use. A robust hardware/software design virtually eliminates the dry-down times often associated with UHP gas checking.

Offering an ultra-sensitive Lower Detection Limit (LDL) of 250ppt, the DF-749 uses industry-leading TDL sensing technology to deliver ultra-reliable baseline measurements and a fast speed of response. 

High-stability TDL measurements

Modern LCD and LED manufacturing processes require an ultra-trace quality measurement for moisture contaminants in high-purity electronics-grade gases. In such a demanding application, users need analysis capable of delivering high-accuracy and ultra-low detection limits in multiple background gases. Regardless of your application requirements, you need a moisture analyzer that can also provide operational efficiencies. We don’t believe you should have to compromise.

A no-compromise solution

The DF-749 NanoTrace is ideal for your applications, combining high-stability trace and ultra-trace measurements with flexible portability. Using state-of-the-art TDL sensing – with zero drift and a fast speed of response – this device provides high stability and accuracy that is ideal for upset-prone applications. With a low LDL of 250ppt and the ability to monitor moisture in multiple background gases with a single unit, the DF-749 NanoTrace delivers a high-accuracy, adaptable monitoring solution, one enhanced by a compact design simplifying port-to-port mobility, making it ideal for either a fixed or cart-based solution.

Service team checklist

Simple maintenance and reduced ongoing costs

Proven sensing technology and advanced functionality deliver DF-749 users a low lifetime cost of ownership. Factory calibration helps facilitate quick and easy installation; data archiving makes the storage and recall of calibration, system errors and measurement data simple. The use of the high-stability TDL sensor – with zero drift intervals – extends calibration intervals and minimizes ongoing maintenance needs enabling considerable savings over a long product lifetime.

Man with Servomex System components

Looking for an integrated system solution?

If you’re building a gas analysis system, we can help. Our expert team works with you to design, build and deliver the project you need to meet your process requirements. Get in touch to learn more.

The benefits of TDL moisture measurement

The robust and ultra-reliable DF-749 provides flexible configuration options and a broad detection range of 0-20ppm.

High reliability

By redirecting 1% of the lasers output intentionally through a reference cell containing water vapor, we eliminate the possibility of the laser output drifting away from the moisture peak. By also continuously sweeping across the full moisture peak curve, we eliminate source/detector changes and any loss in mirror reflectivity by a ratiometric measurement.

Exceptional performance

With a multiple pass ‘Herriott Cell’ we effectively lengthen the absorption path by 50M to increase signal and offer a 250ppt Lower Detection Limit (LDL).

Easy to use

Compact and lightweight, the DF-749 moves easily from port-to-port and is ideal for both rack and cart mobile applications. A tried and tested Guided User Interface (GUI) allows operators low training threshold from one generation to another.

Unrivalled performance

  •  Analysis resistant to gas cell contamination and will meet performance specification with up to 90% signal loss
  •  250ppt Lower Detection Limit (LDL)
  •  Manufactured by Servomex – over 60 years’ experience with thousands of units used in the field


  • 4-20 mA, 0-10 VDC or RS 232/485
  • Broad detection range: 0-20ppm
  • Isolation gas manifold optional

Easy to use

  • Storage and recall; calibration, system error, measurement data and diagnostic history
  • Compact with a low weight; moves easily from port to port and ideal for other mobile applications

Low cost of ownership

  • Robust sensor construction reduces maintenance requirements
  • Zero drift measurement extends calibration intervals

Benchmark compliance

  • IEC 61010-1
  • Overvoltage Category II, Pollution Degree 2
  • CE Marked

Gases sensed, measurements and technologies

The DF-749 uses a TDL sensor to deliver high-stability trace and ultra-trace measurements of moisture as a contaminant in UHP gases.

Gas Measurement
Water vapour (Moisture) (H₂O)ppm, ppt, ppb


Laser Moisture


  • IEC 61010-1
  • Overvoltage Category II, Pollution Degree 2
  • EU EMC Directive
  • EU Low Voltage Directive

Schematics (select to expand)


483mm (19”) Wide x 266mm (10.5”) High x 608mm (23.9”) Deep


31.8kg (70lbs)

Get the detailed specifications

For in-depth specifications you’ll want to download our technical datasheet which includes information on technology, performance, operating environment, sample conditions and compliance along with technical drawings and top-level benefits and applications.”

Joseph Ha
Product Manager, Purity & Speciality

Download the DF-749 resource pack

“Our comprehensive resource pack has all the details you need about the features and benefits of the DF-749. Download it now to ensure you have all the essential details at your fingertips.”


Joseph Ha
Product Manager, Purity & Speciality

Manuals and brochures

Read all about the performance and technical specifications of the DF-749 moisture analyzer – download the product brochure and operator manual today.

DF-700 Gen 7 Recommended Spares

DF-700 Gen 7 Recommended Spares

Gen 7 Quick Guide

Watch our video guide that makes setting up and operating your new Gen-7 SERVOPRO DF-700 NanoTrace Series analyzer as simple as possible.

DF-700 Series Service Flyer-Upgrade

DF-700 Series Service Flyer-Upgrade

See for yourself

Servomex Gas Guide issue 4

Servomex Gas Guide issue 4

Servomex Brand Video

Watch our new film to find out how we analyse change, so we can help you make it happen. We believe that together we create a cleaner, healthier, and more productive world.

Ammonia Application video

See how our gas analysis solutions benefit process control, combustion efficiency, emissions monitoring, and quality in the ammonia production process.

Direct Reduction Iron application video

Discover our key measurement solutions for increased efficiency and reduced emissions in the DRI production process with this application video.

Related videos

Our DF-700 series video reveals more about our trace moisture analyzer range. Watch it now, and discover our expert solutions for moisture measurement applications.

Typical applications

With the capability to measure ultra-trace moisture in a variety of background gases, the DF-749 is ideal for quality checking of UHP gases used in LCD and LED manufacturing applications.

UHP Gases / Semiconductors

A comprehensive systems solution

Learn more

Explore our full range of applications

Still need to know more? Talk to one of our experts

If you haven’t yet been convinced, then speak to our experts. They’ll give you the best, most knowledgeable explanation of our solutions, and help you find the one that’s most suitable for your application.

© Copyright 2024 - Servomex is a Spectris company.
Click here to download your selected documents