On-site hydrogen generators replace acetylene cylinders for hydride generation and cold vapor AAS — delivering sub-ppb trace metal detection for As, Se, Hg, and 20+ other elements without the hazards and cost of stored compressed gas.
Atomic absorption spectroscopy draws on hydrogen, nitrogen, and zero air at different points in the measurement process. On-site generation covers all three from a single equipment footprint.
H₂ is produced alongside volatile hydrides (AsH₃, H₂Se, SbH₃, BiH₃, SnH₄) during NaBH₄ reduction and sweeps them to the quartz tube atomizer. 6N purity is required to prevent catalyst poisoning and spectral interferences.
CV-AAS for mercury generates Hg⁰ vapor via reduction with SnCl₂ or NaBH₄; H₂ acts as the carrier gas sweeping elemental mercury to the optical cell. Achieves sub-ppb detection limits without a flame or furnace.
GFAAS requires an inert gas purge during drying, pyrolysis, and atomization stages to remove matrix vapors and prevent graphite tube oxidation. N₂ delivers the inert atmosphere without the cost of argon cylinder supply.
Hydrocarbon-free synthetic air from the ZA Series provides a clean oxidant for air-acetylene and air-hydrogen flames. Eliminating hydrocarbon contamination from the oxidant reduces flame background emission and improves baseline stability.
Hydride generation AAS (HG-AAS) is the method of choice for ultra-trace determination of arsenic, selenium, antimony, bismuth, lead, tin, tellurium, and germanium — elements where standard flame AA sensitivity is insufficient for environmental, food safety, and clinical matrices. The technique acidifies a sample, adds sodium borohydride (NaBH₄), and the resulting volatile hydrides are swept by hydrogen to a heated quartz tube atomizer above the optical path.
Cold vapor AAS (CV-AAS) extends the same principle to mercury: SnCl₂ or NaBH₄ reduces Hg²⁺ to elemental mercury vapor, which H₂ carries to an unheated absorption cell. This achieves detection limits in the sub-ppb range — without a flame, without a furnace, and without acetylene.
Both techniques require 99.9999% (6N) hydrogen. Hydrocarbon impurities poison the quartz tube surface and introduce spectral background; moisture causes reagent degradation. LNI Swissgas HG Series generators produce 6N H₂ from deionized water on demand — no cylinders, no safety compliance burden, no purity drift between deliveries.
Graphite furnace AAS (GFAAS, also called electrothermal AAS or ET-AAS) achieves detection limits 100–1,000× lower than flame techniques by atomizing microlitre sample volumes directly in a heated graphite tube. The technique cycles through programmed temperature stages: drying removes solvent, pyrolysis burns off the matrix, and atomization vaporizes the analyte at 2,000–2,700°C.
Each stage requires a continuous inert gas purge. The purge gas prevents graphite tube oxidation, removes matrix vapors before atomization, and maintains a stable background during measurement. Argon is the traditional choice, but many modern GFAAS instruments accept nitrogen as an equivalent inert purge at substantially lower cost — making on-site N₂ generation via PSA a practical and economical alternative to argon cylinders.
AAS instruments depend on precise hollow cathode lamp current control, stable photomultiplier tube detector supply voltage, and noise-free signal acquisition electronics. Line voltage fluctuations introduce lamp intensity drift that looks identical to concentration changes — shifting calibration curves and producing false results without triggering any instrument alarm.
A regulated voltage conditioner on the AAS instrument supply eliminates this source of analytical error and protects the lamp power supply from transient damage. For labs where mid-sequence power failures would waste significant sample preparation time — particularly GFAAS autosampler sequences or overnight HG-AAS runs — pairing the conditioner with a UPS ensures any grid event results in a controlled stop, not a corrupted data file.
On-site H₂ and N₂ from SLI cover the full range of hydride-forming, cold-vapor, and furnace AAS analytes used in environmental, food, pharmaceutical, and materials labs.
Purity and flow specifications for all major AAS gas supply roles. Contact SLI for instrument-specific sizing and generator recommendations.
Between acetylene hazards, argon costs, and inter-delivery purity variation, cylinder gases introduce more risk and expense into trace metal analysis than most labs realize.
Acetylene is flammable, shock-sensitive, and subject to strict storage regulations. On-site H₂ generation for HG-AAS produces gas at low pressure on demand — no acetylene stored anywhere in or near the lab.
Cylinder H₂ purity can vary between deliveries. Inter-batch purity changes shift reagent blank values and alter standard curve slopes. On-site generation delivers the same 99.9999% purity every time, from the same source.
High-purity H₂ and N₂ specialty gas cylinders for trace analysis are expensive. On-site generation pays back the capital cost in 12–24 months and then runs on electricity and deionized water only.
EPA Method 200.9, 245.1, 7470A, and related methods specify carrier gas purity. Documented on-site generator output certificates support method compliance records more consistently than cylinder lot-to-lot variation.
Gas shortages, delivery delays, and back-orders have disrupted lab operations in recent years. On-site generation eliminates supply chain dependency — as long as the power is on and DI water is flowing, your H₂ is available.
A single HG PRO generator can serve both HG-AAS and CV-AAS mercury workflows — even simultaneously from separate outlets — consolidating two cylinder supply lines into a single benchtop unit.
LNI Swissgas generators connect to standard gas fittings. Any AAS instrument that accepts H₂, N₂, or zero air from a cylinder works with on-site generation.
PinAAcle 900 series flame/furnace, AAnalyst 400/800, FIAS flow injection HG system
iCE 3000 / 3300 / 3500 series flame & furnace, SOLAAR M6 / S series, SOLAAR M6 GFAAS
240FS AA fast sequential, 240Z GFAAS, 55B/55 Zeeman graphite furnace AAS
AA-7000 / AA-6300 series, HVG-1 hydride vapor generator, AA-6880 GFAAS
contrAA 800 D/G high-resolution CS-AAS, ZEEnit 700 P / 650 P Zeeman GFAAS, HydrEA hydride system
Z-2300 / Z-2700 Zeeman GFAAS, ZA3000 series polarized Zeeman atomic absorption
SavantAA Σ flame AAS, AVANTA M / PM graphite furnace, HG 3000 hydride system
HydraAA CV-AAS mercury analyzer, Tekran 2600 series dissolved mercury — all requiring H₂ carrier
Tell us your technique — HG-AAS, CV-AAS, GFAAS, or flame AA — and we’ll recommend the right generator configuration.