CHNS/O Elemental Analyzer with Oxygen Pyrolysis

What is the CHNS/O Elemental Analyzer with Oxygen Pyrolysis?

A CHNS/O elemental analyzer adds a dedicated pyrolysis reactor so oxygen can be measured by difference-free direct determination alongside C, H, N, and S. It suits laboratories that need a complete organic elemental composition without a separate instrument.

Overview

The CHNS/O elemental analyzer combines two reactor configurations. In CHNS mode, the sample is combusted in oxygen at about 1000 °C as in a standard analyzer. In oxygen mode, the reactor is switched to a pyrolysis tube packed with nickel-coated carbon and held near 1060 °C under pure helium, so oxygen in the sample converts quantitatively to CO. The CO is separated on a column and detected by the thermal conductivity detector, with silver capsules used in place of tin. Many systems switch between modes using software-controlled valves and a dual-reactor layout, while simpler models require manual tube exchange. Direct oxygen determination is more reliable than calculating by difference, especially for compounds containing halogens, metals, or ash. Typical oxygen range is 0.1–50%, and nitrogen and sulfur are unaffected in CHNS mode.

How does it work?

A CHNS analyzer drops a weighed sample of 1–10 mg, sealed in a tin capsule, into a combustion reactor held at roughly 950–1150 °C while a timed oxygen pulse is injected. The tin oxidizes exothermically and lifts the local temperature to about 1800 °C, converting the sample to CO2, H2O, N2, nitrogen oxides, and SO2. A helium carrier gas sweeps these products through a reduction zone of hot copper, which converts nitrogen oxides to N2 and removes excess oxygen. Water traps or a chromatographic column then separate the gases. A thermal conductivity detector measures each in turn and the software integrates peak areas against a calibration with a standard such as acetanilide or sulfanilamide. Oxygen mode uses pyrolysis over nickel-coated carbon to form CO.

What are the key features?

• Direct oxygen determination by pyrolysis over nickel-coated carbon at about 1060 °C.
• Dual-reactor option switches between CHNS and O modes through software-controlled valves.
• Silver capsules for oxygen mode avoid oxygen contribution from tin oxide.
• Single thermal conductivity detector serves both combustion and pyrolysis gas streams.
• Complete composition check reduces reliance on calculated oxygen by difference.
• Reactor life monitoring reminds users when pyrolysis carbon packing needs replacement.

What are the technical specifications?

A typical chns/o elemental analyzer with oxygen pyrolysis configuration offers elements measured of C, H, N, S, O, oxygen range of 0.1–50%, sample mass of 1–5 mg, pyrolysis temperature of 1050–1080 °C, combustion temperature of Up to 1150 °C and oxygen repeatability (RSD) of ≤0.3% (benzoic acid standard). Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The CHNS/O Elemental Analyzer with Oxygen Pyrolysis is used in complete composition of new organic compounds, polymer and resin oxygen content, biomass and biofuel characterization and pharmaceutical excipient verification. Across the wider CHNS Analyzers class, laboratories also deploy it for organic synthesis and purity confirmation, pharmaceutical raw material QC and polymer and battery material composition.

Which standards and certifications apply?

Relevant standards and methods include ASTM D5373, ISO 29541, ASTM D5291, ASTM E1019, USP <233>, ISO/IEC 17025 and IEC 61010-1. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Install in a draft-free room with stable temperature and a vibration-free bench for the microbalance. Helium of 99.999% purity and oxygen of 99.995% purity are typical, and gas leaks are the most common cause of drift. Calibrate with a certified standard in multiple weights and run blanks and conditioning samples at the start of each day. Replace the combustion tube packing, reduction copper, and water trap on a schedule based on sample count, usually every 300–1000 samples. Halogenated and high-ash samples consume consumables faster and may need additives such as vanadium pentoxide. Laboratories under GLP or ISO/IEC 17025 should record system suitability using check standards and keep balance calibration records.

How do I select the right CHNS/O Elemental Analyzer with Oxygen Pyrolysis?

Select the CHNS/O analyzer when direct oxygen data is needed for organics, polymers, or biomass, and one instrument must serve both modes. Specify whether simultaneous dual reactors or manual switching is acceptable, oxygen range, capsule types, and autosampler size. If oxygen is rarely needed, a CHNS-only instrument reduces cost and maintenance.

How does it compare with other CHNS Analyzers variants?

The main decision is the set of elements and the sample type. A CHN configuration suits most organic synthesis work, while CHNS adds a sulfur channel and requires a column able to resolve SO2. Add oxygen pyrolysis if O is required. Microbalance resolution governs precision for small samples, so specify 0.001 mg for 1–2 mg weighing. Autosampler capacity of 50–120 positions matters for routine throughput. Liquid and volatile samples need sealed capsules or a liquid-capable module. Large-sample and heterogeneous materials such as soil, coal, and biomass benefit from macro analyzers handling 100 mg to several grams. Check whether the vendor documents accuracy, typically within 0.3% absolute of theoretical values for pure standards, and whether the software supports 21 CFR Part 11 style audit trails if used in regulated laboratories.