Micro CHNS Elemental Analyzer

What is the Micro CHNS Elemental Analyzer?

A micro CHNS elemental analyzer burns 1–3 mg organic samples by dynamic flash combustion and reports carbon, hydrogen, nitrogen, and sulfur. It is the standard choice for synthetic chemistry and pharmaceutical laboratories that need to confirm empirical formulas within 0.3% absolute.

Overview

The micro CHNS elemental analyzer is a benchtop instrument built around a vertical quartz combustion reactor, a reduction zone, a gas separation column, and a thermal conductivity detector. A microbalance with 0.001 mg readability is either integrated or paired with the analyzer. Samples are weighed into tin capsules and dropped from a 50–120 position autosampler into the reactor at 1000–1150 °C during an oxygen pulse. Run time is typically 5–10 minutes per sample, and the four elements are measured in a single run. Helium carrier flow is about 100–140 mL/min. Software controls furnace temperature, gas timing, calibration by K-factor or linear regression, and result reporting with blank correction. Because the sample mass is small, it is suited to precious, synthesized, or limited-quantity materials, but it demands homogeneous powders and careful weighing.

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?

• Flash combustion up to 1150 °C reaches complete oxidation of most organic matrices.
• Single-run determination of C, H, N, and S from 1–3 mg of sample.
• Autosampler with 50–120 positions supports unattended overnight batches.
• Thermal conductivity detector with temperature-controlled cell gives stable baselines.
• Optional oxygen pyrolysis configuration using a separate reactor.
• Software supports blank correction, K-factor calibration, and audit trail.

What are the technical specifications?

A typical micro chns elemental analyzer configuration offers elements measured of C, H, N, S (O optional), sample mass of 1–10 mg, carbon range of 0.01–100%, nitrogen range of 0.01–100%, repeatability (RSD) of ≤0.2% (acetanilide standard) and combustion temperature of Up to 1150 °C. 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 Micro CHNS Elemental Analyzer is used in organic compound purity confirmation, pharmaceutical API and intermediate testing, polymer and catalyst characterization and academic microanalysis service laboratories. 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 Micro CHNS Elemental Analyzer?

Select the micro CHNS when sample quantities are small, the matrix is homogeneous organic powder, and journal-grade agreement within 0.3% is required. Choose a macro analyzer instead for heterogeneous solids. In an RFQ, specify elements required (including S or O), microbalance readability, autosampler positions, helium consumption, and whether audit-trail software is needed.

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.