LECO CHNS628 Organic Elemental Analyzer

Overview

The LECO CHNS628 Organic Elemental Analyzer is a high-throughput, Dumas combustion-based instrument engineered for precise quantification of carbon (C), hydrogen (H), nitrogen (N), and sulfur (S) in organic matrices. It operates on the principle of flash combustion at controlled high temperature (up to 1050 °C) in an oxygen-rich environment, followed by selective gas-phase detection using non-dispersive infrared (NDIR) absorption for CO₂ and H₂O, and thermal conductivity detection (TCD) for N₂ and SO₂ after catalytic reduction and chemical scrubbing. This architecture ensures complete oxidation of refractory organics while minimizing interferences from halogens, metals, or heteroatoms—critical for pharmaceuticals, polymers, agricultural feedstuffs, and environmental samples. The system delivers fully quantitative results in just 4.5 minutes per sample, supporting routine QC, method validation, and regulatory submissions under ISO 14852, ASTM D5291, USP , and AOAC 992.23.

Key Features

• Dual-furnace combustion design: Primary furnace (up to 1050 °C) ensures complete sample oxidation; secondary furnace (650–850 °C) eliminates residual carbonaceous particulates and oxidizes NO_x to N₂.
• Optimized gas handling: Integrated pre-cooler and thermoelectric cooler remove water vapor prior to gas sampling; high-efficiency chemical traps (magnesium perchlorate, sodium hydroxide asbestos) eliminate residual CO₂ and H₂O before TCD analysis.
• Modular configuration flexibility: Supports CHN, CN, FP (Kjeldahl-equivalent nitrogen/protein), and CHNS operational modes via software-selectable hardware routing and detector activation.
• 30-position autosampler with stackable expansion capability (up to 120 positions): Enables unattended overnight runs with full sample mass tracking and positional logging.
• Robust gas control architecture: Independent pressure-regulated supply lines for helium carrier, ultra-pure oxygen combustion gas, and oil-free dry drive air—each monitored in real time with fault logging.
• Calibration traceability: Factory-calibrated with NIST-traceable standards (e.g., benzoic acid, acetanilide, sulfanilamide); supports user-defined calibration curves with multi-point verification.

Sample Compatibility & Compliance

The CHNS628 accommodates solid, powdered, and homogenized biological or synthetic organic materials—including pharmaceutical actives, polymer additives, soil extracts, food products, and catalyst supports. Sample masses range from 1–750 mg depending on elemental concentration and matrix volatility, with automated mass entry via balance interface (RS-232 or USB). All analytical protocols comply with Good Laboratory Practice (GLP) and support 21 CFR Part 11 compliance when paired with LECO’s validated software package, which includes electronic signatures, audit trails, data integrity controls, and locked method templates. Instrument qualification documentation (IQ/OQ/PQ) is available per ASTM E2500 and ISO/IEC 17025 requirements.

Software & Data Management

Controlled via LECO’s Windows-based Elementar™ software, the CHNS628 provides integrated instrument control, real-time chromatogram visualization, peak integration, stoichiometric correction (e.g., moisture-, ash-, or chloride-corrected reporting), and customizable report generation. Data files are stored in encrypted binary format with SHA-256 hash verification. The software supports export to CSV, XML, and LIMS-compatible formats (ASTM E1384, HL7), and includes built-in tools for uncertainty propagation, recovery calculation, and statistical process control (SPC) charting. Audit logs record all user actions—including method edits, calibration events, and result overrides—with timestamp, operator ID, and IP address where networked.

Applications

• Pharmaceutical QA/QC: Assay verification of active pharmaceutical ingredients (APIs), excipient purity screening, and stability-indicating elemental profiling per ICH Q5E guidelines.
• Agricultural & Feed Analysis: Protein content determination (via nitrogen-to-protein conversion), fertilizer composition verification, and mycotoxin-contaminated grain screening.
• Polymers & Composites: Carbon black loading quantification, flame retardant (e.g., melamine, ammonium polyphosphate) verification, and halogen-free certification support.
• Environmental Testing: Total organic carbon (TOC) in soils/sediments, sulfur content in coal and biofuels, and nitrogen speciation in wastewater sludge per EPA Method 418.1.
• Academic & Contract Research: High-precision stoichiometric validation of novel synthetic compounds, coordination complexes, and MOFs prior to publication or patent filing.

FAQ

What combustion principle does the CHNS628 use?
It employs high-temperature Dumas combustion (flash oxidation) in pure oxygen, followed by catalytic reduction and selective gas-phase detection—distinct from Kjeldahl digestion and eliminating wet chemistry hazards.

Can the instrument analyze sulfur without hardware modification?
Yes—the CHNS628 includes dedicated SO₂ detection path, sulfur-specific catalysts, and calibrated SO₂ NDIR cell as standard; no field retrofitting required.

Is method validation support included?
LECO provides comprehensive validation packages including system suitability tests, specificity studies, LOD/LOQ determination protocols, and linearity verification templates aligned with ICH Q2(R2).

How is data integrity ensured during long unattended runs?
Each analysis generates a unique digital fingerprint; raw signal files, processed results, and audit logs are write-protected upon acquisition and cannot be altered retroactively.

What maintenance intervals are recommended for optimal performance?
Quarterly replacement of combustion tube liners and CO₂/H₂O scrubbers; biannual TCD filament inspection; annual full gas-path leak test and furnace calibration verification—all tracked automatically within the software maintenance scheduler.