High-flow, high-purity nitrogen for ESI desolvation, curtain gas, collision cell operation, and ELSD detection — generated on-site with built-in oil-free compressors. No cylinders, no downtime, no interruptions to overnight runs.
LC-MS systems are among the highest-volume nitrogen consumers in the lab. A single instrument can use 15–30 L/min continuously. Here is where all that nitrogen goes.
Heated nitrogen strips solvent from droplets as they enter the ion source, converting liquid eluent into gas-phase ions. This is the single largest nitrogen consumer on an LC-MS — typically 10–20 L/min.
A curtain of nitrogen sweeps across the entrance to the mass analyzer, preventing neutral molecules and solvent clusters from contaminating the vacuum region and degrading sensitivity over time.
In tandem MS/MS experiments, nitrogen in the collision cell fragments precursor ions into diagnostic product ions for structural identification and quantitation in MRM mode.
Evaporative Light Scattering Detectors use nitrogen to nebulize and evaporate LC eluent, leaving non-volatile analyte particles that scatter a laser beam. Requires clean, dry, oil-free nitrogen.
When you add desolvation (10–20 L/min) + curtain (3–10 L/min) + collision cell (0.5–3 L/min), a single triple-quad LC-MS consumes 15–30 L/min of nitrogen continuously. At 8 hours per day, that is 7,200–14,400 liters — roughly one high-pressure cylinder every 1–2 hours. This is why LC-MS labs are the #1 adopters of on-site nitrogen generators.
Electrospray ionization (ESI) is the most common ion source for LC-MS. It converts liquid eluent into gas-phase ions by spraying through a charged capillary. Heated nitrogen (200–600 °C) surrounds the spray to evaporate solvent and desolvate ions efficiently.
Higher desolvation gas flow and temperature generally improve sensitivity and reduce matrix effects — but this requires sustained, high-volume nitrogen delivery that cylinders cannot practically provide. A single LC-MS running at optimal desolvation settings consumes a nitrogen cylinder every 1–2 hours.
Why membrane generators are ideal: LC-MS desolvation does not require ultra-high purity (95–99.5% is sufficient). Membrane nitrogen generators deliver exactly this purity range at high flow rates (20–70 L/min) with built-in oil-free compressors — no external compressed air needed. This makes them the most cost-effective solution for LC-MS nitrogen supply.
Running 2–3 LC-MS instruments? A single NG CASTORE XL iQ 70 delivers 70 L/min — enough to feed three instruments simultaneously from one unit. No manifolds, no cylinder racks, no delivery schedules.
In MS/MS (tandem) mode, precursor ions are selected in Q1, accelerated into a collision cell (Q2) filled with an inert gas, and fragmented by collision-induced dissociation (CID). The resulting product ions are analyzed in Q3.
Nitrogen is the standard CID gas for most triple-quadrupole and QTOF LC-MS systems. It provides efficient fragmentation across a wide mass range while being readily available from the same generator supplying your desolvation gas.
The flow required for CID is relatively low (0.5–3 L/min), but purity matters more here than for desolvation. Contaminants in the collision cell can create chemical noise, reduce fragment ion yield, and degrade MRM sensitivity over time. A membrane generator delivering 99–99.5% purity with documented hydrocarbon and moisture levels is more than adequate.
ELSD (Evaporative Light Scattering Detection) and CAD (Charged Aerosol Detection) are universal LC detectors that work with any non-volatile analyte — no UV chromophore needed. Both require clean, dry, oil-free nitrogen to nebulize the eluent and evaporate the solvent.
Oil contamination is the #1 enemy: Even trace oil in the nebulizer gas creates a persistent background signal and contaminates the detector optics. This is why ELSD manufacturers specifically recommend against using house compressed air and require either cylinder nitrogen or an oil-free nitrogen generator.
A membrane generator with a built-in oil-free compressor delivers exactly the right purity (95%+) and dryness for ELSD at 1–3 L/min. The NG CASTORE XS iQ is purpose-built for this application — compact, quiet, and completely oil-free.
Many UHPLC systems run an ELSD in parallel with the mass spectrometer as a complementary detector. The NG CASTORE XL iQ has enough capacity to feed both the LC-MS (desolvation + curtain + CID) and the ELSD simultaneously from a single unit.
Quick reference for nitrogen requirements by LC-MS type and number of instruments.
| Configuration | N₂ Flow Required | Purity | Recommended Generator | Notes |
|---|---|---|---|---|
| Single Quad LC-MS ENTRY | 10–15 L/min | >95% | NG CASTORE XS iQ 15 | Desolvation + nebulizer only |
| Triple Quad (QQQ) | 15–25 L/min | >95% | NG CASTORE XS iQ 24/36 | + CID collision cell gas |
| QTOF | 15–30 L/min | >95% | NG CASTORE XL iQ 40 | Higher curtain gas flow |
| 2 × Triple Quad | 30–50 L/min | >95% | NG CASTORE XL iQ 50 | One generator, two instruments |
| 3 × LC-MS (mixed) | 45–70 L/min | >95% | NG CASTORE XL iQ 70 | Maximum single-unit capacity |
| 4+ LC-MS / Central Supply | 70–350 L/min | >95% | NG CASTORE PRO / BASIC | External compressor required |
| ELSD / CAD (standalone) | 1–3 L/min | >95% | NG CASTORE XS iQ 15 | Oil-free critical |
LC-MS labs consume more nitrogen than any other analytical technique. On-site generation delivers the biggest ROI.
LC-MS labs consuming 2–3 cylinders per day see payback in 3–6 months. After that, your nitrogen is essentially free. No gas invoices, no rental, no delivery fees.
Automated overnight LC-MS/MS sequences run to completion every time. No more arriving Monday to find your 200-sample batch failed at sample #47 because nitrogen ran out.
Run your desolvation gas at the manufacturer’s recommended flow without worrying about cylinder consumption. Higher flow = better sensitivity = better detection limits.
Eliminate cylinder delivery scheduling, receiving, swapping, leak testing, and inventory management. Your lab staff focuses on science, not gas logistics.
Documented, consistent gas quality from your generator means stable spray conditions, reproducible ionization efficiency, and reliable quantitation day after day.
NG CASTORE iQ models include an integrated oil-free compressor. No house air connection needed. Plug into power, connect to your LC-MS, and start generating nitrogen.
Our nitrogen generators are instrument-agnostic and support every LC-MS, UHPLC, and ELSD platform from every major manufacturer.
Xevo TQ-S, Xevo TQ-XS, Xevo G3 QTof, SYNAPT XS, ACQUITY UPLC. All ESI and APCI nitrogen gas configurations.
6495C, 6546 QTOF, 6560 IM-QTOF, 1290 Infinity II UHPLC. Jetstream and AJS ESI source gas support.
TSQ Altis/Fortis, Q Exactive, Orbitrap Exploris, Vanquish UHPLC. HESI and APCI source nitrogen compatibility.
Triple Quad 7500, X500R QTOF, QTRAP 6500+, ExionLC AD. Turbo V, IonDrive Turbo V source gas support.
LCMS-8060NX, LCMS-9050, Nexera UHPLC series. All heated ESI and DUIS source configurations.
timsTOF Pro 2, timsTOF SCP, EVOQ TQ, Elute UHPLC. CaptiveSpray and ESI source gas supply.
Thermo CAD, Agilent 380-ELSD, SEDEX 90 LT-ELSD, Shimadzu ELSD-LT III. Clean, oil-free nitrogen supply.
Central nitrogen supply for labs running 2–6+ LC-MS instruments. One NG CASTORE XL iQ 70 feeds three instruments simultaneously.
Tell us how many LC-MS instruments you run, which platforms you use, and whether you need ELSD support. We will size the right generator and calculate your ROI.