Eliminate CO₂ and water vapor absorption bands from your infrared spectra with dry, moisture-free nitrogen purge gas — generated on-site for stable baselines, reproducible measurements, and zero cylinder logistics.
Atmospheric CO₂ and water vapor absorb infrared radiation at specific wavelengths, creating interference bands that obscure analyte signals, distort baselines, and reduce measurement accuracy.
Dry nitrogen flows through the spectrometer’s optical bench, displacing atmospheric CO₂ and water vapor from the IR beam path between source, interferometer, sample compartment, and detector.
For hygroscopic or moisture-sensitive samples, a dedicated nitrogen purge around the sample compartment prevents atmospheric water from interacting with your sample during measurement, ensuring accurate results.
MCT (mercury cadmium telluride) detectors and certain accessories like ATR crystals and microscope stages benefit from nitrogen purging to prevent moisture condensation and extend component lifespan.
Atmospheric carbon dioxide absorbs strongly at 2349 cm⁻¹ (asymmetric stretch) and 667 cm⁻¹ (bending mode). Water vapor produces broad, complex absorption across 3500–3900 cm⁻¹ and 1300–1900 cm⁻¹. These bands can overlap with analyte peaks, distort baselines, and make quantitative measurements unreliable.
Software subtraction is not enough. While modern FTIR software can subtract atmospheric contributions, this approach introduces noise, creates artifacts near strong atmospheric bands, and fails when ambient conditions change between background and sample scans. Physical removal of CO₂ and H₂O by nitrogen purging is always superior.
Dry nitrogen purge eliminates the problem at the source. By flooding the optical path with dry, CO₂-free nitrogen, you remove atmospheric absorbers physically rather than mathematically. The result: cleaner baselines, lower noise floors, and reliable spectra in the critical fingerprint region.
PSA generators (NG EOLO series) deliver the driest nitrogen with the lowest dew point — ideal for demanding applications like far-IR spectroscopy, ATR microscopy, and humid laboratory environments. Membrane generators (NG CASTORE series) provide excellent purity at higher flow rates for labs running multiple FTIR instruments or combining purge gas with LC-MS nitrogen.
NIR spectroscopy: Near-infrared instruments operating in the 4000–12000 cm⁻¹ range are less affected by CO₂ but still sensitive to water vapor overtone and combination bands. Nitrogen purging is essential for quantitative NIR measurements in pharmaceutical, food, and polymer applications.
FTIR microscopy: IR microscopes with MCT detectors require continuous nitrogen purge to prevent moisture condensation on the cooled detector element. Even brief exposure to humid air can degrade MCT performance and require extended re-purging before measurements resume.
TGA-FTIR / GC-FTIR hyphenation: When FTIR is coupled to thermogravimetric analyzers or gas chromatographs, the transfer line and gas cell require nitrogen purge gas in addition to the spectrometer bench. This increases total nitrogen demand to 5–15 L/min.
Process FTIR: In-line and at-line FTIR analyzers in manufacturing environments require robust, continuous nitrogen supply. An on-site generator eliminates the risk of cylinder depletion during 24/7 process monitoring.
Quick reference for nitrogen purge requirements by FTIR configuration.
| Configuration | N₂ Flow | Purity | Key Requirement | Recommended Generator |
|---|---|---|---|---|
| Single FTIR (bench purge) MOST COMMON | 2–5 L/min | >99.5% | Dry, CO₂-free | NG EOLO 500 / 750 |
| FTIR + ATR accessory | 3–7 L/min | >99.5% | Dry, continuous | NG EOLO 750 / 1300 |
| FTIR microscope (MCT) | 3–8 L/min | >99.999% | Ultra-dry, oil-free | NG EOLO 1300 (PSA) |
| TGA-FTIR / GC-FTIR | 5–15 L/min | >99.5% | Higher flow for transfer line | NG EOLO 4000 / SIRIO |
| NIR (quantitative) | 2–5 L/min | >99.5% | H₂O removal critical | NG EOLO 750 |
| 2–3 FTIR instruments | 6–15 L/min | >99.5% | Central supply | NG EOLO 4000 / SIRIO 1500 |
| Process FTIR (24/7) | 5–20 L/min | >99.5% | Continuous, uninterrupted | NG CASTORE XS iQ |
| FTIR + LC-MS shared supply | 20–50 L/min | >95% | High flow for both | NG CASTORE XL iQ |
On-site nitrogen generation transforms FTIR purge gas from a recurring expense and logistical hassle into a set-and-forget utility.
Consistent, dry nitrogen produces stable, reproducible baselines. No more spectral artifacts from atmospheric fluctuations between background and sample scans.
Your FTIR stays purged 24/7 — no more Monday morning re-purge cycles because the weekend cylinder ran empty and humidity crept back into the optical bench.
FTIR purge gas is a low-flow, continuous application that burns through cylinders slowly but steadily. A generator eliminates the recurring expense permanently.
The water vapor rotation spectrum (below 500 cm⁻¹) is particularly dense. Effective purging unlocks the far-infrared region for lattice vibration, hydrogen bonding, and metal-ligand studies.
Continuous nitrogen purge prevents moisture condensation on liquid-nitrogen-cooled MCT detector elements, extending detector lifespan and maintaining sensitivity.
Removing atmospheric interference from the beam path improves the accuracy of quantitative methods, especially for analytes with bands near 1600, 2350, or 3500 cm⁻¹.
Our nitrogen generators are instrument-agnostic and support every FTIR, NIR, and IR microscopy platform from every major manufacturer.
Nicolet iS50, iS20, Summit. iN10/iN10 MX FTIR microscopes. Nicolet iG50 research grade. All purge gas configurations.
INVENIO, VERTEX 70v, ALPHA II, LUMOS II FTIR microscope. Vacuum and purge bench options. HYPERION microscope support.
Cary 630, Cary 660 FTIR. 4300 Handheld FTIR. 4500a portable. Laser direct infrared (LDIR). All bench purge configurations.
Spectrum 3 / 3 MIR/NIR/FIR. Spectrum Two. Spotlight 150i/200i/400 FTIR microscopes. Frontier NIR/MIR/FIR.
IRXross, IRSpirit, IRTracer-100 FTIR. AIM-9000 FTIR microscope. Full nitrogen purge compatibility.
FT/IR-4X, FT/IR-6X series. IRT-5200 FTIR microscope. VIR series. Vacuum and purge instrument options.
Metrohm NIRS, FOSS NIR, Bruker MPA II, ABB FTPA2000. Process and at-line NIR analyzers with nitrogen purge.
Thermo TGA-IR, PerkinElmer TGA 8000, Bruker TGA-IR. Hyphenated systems requiring additional purge gas for transfer lines.
Tell us which FTIR or NIR instruments you run, whether you use MCT detectors or microscopy accessories, and your current purge gas setup. We will recommend the right nitrogen generator for your spectroscopy lab.