Xianjian KDN-20K Fully Automated Kjeldahl Nitrogen Determinator

Overview

The Xianjian KDN-20K Fully Automated Kjeldahl Nitrogen Determinator implements the classical Kjeldahl digestion–distillation–titration methodology in a fully integrated, microprocessor-controlled platform. Designed for quantitative nitrogen determination in organic matrices—including food, feed, soil, wastewater, and pharmaceutical raw materials—the instrument executes acid digestion (typically with concentrated H₂SO₄ and catalyst), alkaline distillation, and potentiometric or colorimetric titration without manual intervention. Its core architecture is engineered for precision, reproducibility, and compliance with internationally recognized analytical protocols. The system operates on a closed-loop logic engine that dynamically adjusts titration speed based on real-time pH or endpoint signal slope, enabling robust handling of both low-nitrogen (e.g., environmental water) and high-protein (e.g., soy flour, dairy powder) samples within a single run sequence.

Key Features

• Triple-tier user permission management (Administrator, Supervisor, Operator) with encrypted login and audit-trail-capable session logging
• Dynamic titration control: three-stage variable-speed delivery (0.5–10 s/drop), auto-adjusted based on analyte concentration and endpoint kinetics
• Integrated blank determination workflow: one-touch blank run with automatic subtraction and database registration
• Self-cleaning cycle: automated steam distillation without reagents (“blank蒸”) to clear condenser tubes and receiver vessels
• Real-time process monitoring: evaporator water level, temperature, and pressure sensors; condenser water flowmeter with low-flow alarm; digestion tube and receiver vessel LED illumination with motion-activated activation
• Independent reagent delivery: seven miniature peristaltic pumps + one stepper-motor-driven mechanical actuator for precise, cross-contamination-free fluid handling
• Acid-resistant splash guard: injection-molded high-performance polymer resistant to concentrated H₂SO₄, NaOH, and H₃BO₃ solutions
• Dual operation mode: seamless switching between fully automated and stepwise manual control for method development or troubleshooting
• Titrant volume calibration: automatic endpoint volume correction using built-in reference standards

Sample Compatibility & Compliance

The KDN-20K accommodates solid samples up to 8.0 g and liquid samples up to 30.0 mL—extended to 300 mL for regulatory water testing applications per HJ 717–2014 and GB 11891–1989. Its nitrogen recovery rate of ≥99.5% meets ISO 8968-1:2014 and AOAC 981.10 validation criteria. The instrument supports six preloaded calculation formulas aligned with major national and industry standards, including GB 5009.5–2016 (food), GB/T 6432–2018 (feed), GB/T 22923–2008 (fertilizer), GB 11891–1989 (water), NY/T 525–2021 (organic fertilizer), and HJ 717–2014 (wastewater). All operational parameters—including method selection, reagent volumes, distillation time, and titration thresholds—are configurable and stored with timestamped metadata, supporting GLP/GMP-aligned data integrity requirements.

Software & Data Management

The embedded 7-inch capacitive touchscreen interface runs a deterministic real-time OS with >30,000 method program slots and >30,000 test record storage capacity. Data export is supported via USB 2.0 mass storage mode (CSV/Excel-compatible format), enabling offline statistical analysis and LIMS integration. Audit trails record all user actions—including login/logout, parameter changes, blank runs, cleaning cycles, and calibration events—with immutable timestamps. Optional firmware updates preserve backward compatibility and extend formula library support upon request. The system complies with FDA 21 CFR Part 11 principles for electronic records and signatures when deployed with network authentication and external time-server synchronization.

Applications

The KDN-20K serves laboratories requiring traceable, high-throughput nitrogen quantification across regulated and research environments. Typical use cases include protein content verification in QC labs (using N-to-protein conversion factors per AOAC guidelines), total Kjeldahl nitrogen (TKN) assessment in municipal wastewater treatment plants, nutrient profiling in agricultural extension services, and raw material screening in pharmaceutical excipient manufacturing. Its extended liquid capacity and dynamic titration make it especially suitable for low-concentration environmental matrices where precision at sub-mg N levels is critical.

FAQ

Does the KDN-20K comply with ISO/IEC 17025 method validation requirements?
Yes—the instrument’s documented recovery, repeatability, and linearity performance align with ISO/IEC 17025:2017 Clause 7.2.2 for method verification. Full validation reports are available upon request.
Can the system be integrated into a laboratory information management system (LIMS)?
Yes—via standardized CSV export and optional RS-232/USB CDC virtual COM port output for direct instrument-to-LIMS telemetry.
What safety certifications does the instrument hold?
It conforms to IEC 61010-1:2010 for electrical safety in laboratory equipment and includes dual thermal cutoffs, pressure relief valves, and interlocked door sensors.
Is remote diagnostics or firmware update supported?
Firmware updates are performed locally via USB; remote diagnostic access is not enabled by default but can be provisioned under controlled IT governance policies.
How is data integrity ensured during power interruption?
Non-volatile flash memory retains all method configurations and recent test results; distillation/titration sequences resume from last valid checkpoint after reboot.