Macro CHNS Elemental Analyzer

What is the Macro CHNS Elemental Analyzer?

A macro CHNS elemental analyzer handles 50 mg to several grams of heterogeneous material such as coal, soil, biomass, or fertilizer. It gives more representative results than micro instruments when samples cannot be homogenized to milligram scale. It is typically used for coal methods.

Overview

The macro CHNS elemental analyzer uses a larger combustion reactor and ceramic crucibles or large tin foil cups to combust 50 mg to 2 g of sample in an oxygen-rich atmosphere. Combustion products pass through a halogen and particulate trap, a reduction furnace, and dedicated infrared or thermal conductivity detectors. Because the sample amount is higher, the representativeness of the aliquot improves for materials with particle heterogeneity such as coal, soils, sludge, and animal feed. Typical temperature is 950–1150 °C with oxygen dosing time programmable per matrix. Carbon and sulfur are often detected by infrared cells and hydrogen by IR or TCD after water separation, while nitrogen uses TCD. Autosamplers of 30–100 positions accept large-volume crucibles. Analysis time is typically 5–8 minutes, and ash removal tools are included to keep the reactor clean.

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?

• Accepts 50 mg to 2 g samples for representative analysis of heterogeneous solids.
• Infrared detection for C, H, and S with TCD for N extends dynamic range.
• Large ceramic crucibles and ash removal tools keep reactor maintenance simple.
• Programmable oxygen dosing adapts combustion to coal, soil, and biomass matrices.
• Autosampler of 30–100 positions supports routine ultimate analysis batches.

What are the technical specifications?

A typical macro chns elemental analyzer configuration offers elements measured of C, H, N, S, sample mass of 50 mg–2 g, carbon range of 0.05–100%, hydrogen range of 0.05–20%, nitrogen range of 0.01–30% and sulfur range of 0.01–20%. 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 Macro CHNS Elemental Analyzer is used in coal and coke ultimate analysis, soil and sediment carbon and nitrogen, biomass and biochar characterization and fertilizer and animal feed testing. 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 Macro CHNS Elemental Analyzer?

Choose the macro CHNS analyzer when samples are coarse, inhomogeneous, or cannot be ground to fine powder, and when methods such as ASTM D5373 or ISO 29541 are required. Specify sample mass range, crucible type, detectors, autosampler capacity, and ash handling. For pure organic compounds in milligram quantities, a micro CHNS is more suitable.

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.