Modern laboratories rely on nitrogen gas for many processes, including LC-MS and GC carrier gas, sample preservation, and glove box purging. While many have traditionally used gas cylinders, more labs now choose nitrogen generators for greater safety, efficiency, and cost savings. With so many models available, selecting the right nitrogen generator can be challenging. Use our Laboratory Nitrogen Generator Guide to make an informed decision.
Consider the following points when contacting suppliers:
1. Understand Your Nitrogen Requirements
Start by identifying what you’ll be using nitrogen for:
- Analytical instrumentation (e.g. LC-MS, GC): These often require high-purity nitrogen (95%–99.999%).
- Sample preparation: Lower purity may be acceptable.
- Purge and blanketing: Flow rate is often more critical than purity.
Document your flow rate (L/min or SCFH), pressure (bar or psi), and purity (%) requirements for each application. Often this can be found in the instrument manufacturer’s site preparation guide. It is also possible for nitrogen flow rates to be calculated from cylinder or liquid nitrogen usage. This can be particularly helpful for purging, blanketing and sample preparation requirements where an exact flow rate per minute can’t be determined.
2. Purity Matters—But Don’t Overdo It
Specifying a higher purity than is actually needed can increase the initial purchase cost. Although 99.999% (5.0 grade) is needed for GC carrier gas, LC-MS requires purity between 95–99.5%. Select a generator with the correct purity and you can save on both upfront and operating costs. For customers switching from liquid nitrogen, it’s best to use the purity needed by the application or instrument rather than requesting quotes for like for like purity.
3. Choose the Right Technology
There are two main types of technology which gas generators use to produce nitrogen.
- Membrane Nitrogen Generators: Generally suited to lower-purity needs (typically up to 99.5%). The initial cost may be lower, however, the membrane will require to be replaced over time which can cost up to 75% of the original purchase cost.
- Pressure Swing Adsorption (PSA) Generators: Deliver higher purity (up to 99.9995%) and drier nitrogen. The CMS adsorbent regenerates continuously and has a lifetime of 10 years plus.
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4. Sizing It Right—Now and for the Future
Select a generator that can meet peak demand without overloading. But also consider:
- The effect of downtime on your processes
- Future expansion plans
- Multi-instrument support
Tip: Factoring in a 20% margin for flow rate ensures the laboratory nitrogen generator isn’t running at full capacity continuously and will improve the service lifetime of critical components.
5. Integration and Footprint
Nitrogen generators come in various forms:
- Standalone units
- Wall-mounted units
- Rack-integrated systems
- Centralised nitrogen generators gas piped to the various points of use. For example the MaxiFlow 100 can supply 3/4 LCMS instruments from one generator.
Tip: Evaluate your lab space, choose an appropriate installation location and consider noise levels. Some units operate quietly enough for lab use, while others work better in utility rooms.
6. Maintenance and Service Support
Ask potential suppliers to provide information on:
- Annual Maintenance costs & Service back-up
- Compressor maintenance
- Remote monitoring capabilities
- Warranty and service agreements
7. Total Cost of Ownership (TCO)
Calculate the potential costs over the generator’s expected life to see your return on investment and support future budgeting. Be sure to consider ongoing costs such as:
- Energy consumption
- Maintenance costs
- Compressor wear and tear
- Downtime and productivity loss
Conclusion
To choose the right nitrogen generator, assess your lab’s current and future needs, and partner with a reputable supplier. This approach helps you reduce gas costs, boost efficiency, and create a safer lab environment.
