Zhiyue KDN-380F Semi-Automatic Kjeldahl Nitrogen Determinator

Overview

The Zhiyue KDN-380F Semi-Automatic Kjeldahl Nitrogen Determinator is an engineered solution for quantitative nitrogen analysis based on the internationally standardized Kjeldahl method (ISO 8968-1, AOAC 984.13, ASTM D1122, and USP <467>). This instrument functions primarily as a precision steam distillation unit following acid digestion—enabling reliable conversion of ammonium salts into volatile ammonia under alkaline conditions, followed by quantitative trapping in boric acid solution for subsequent titrimetric quantification. Designed for routine laboratory environments where throughput, reproducibility, and operational safety are critical, the KDN-380F integrates robust thermal control, programmable reagent delivery, and fail-safe distillation monitoring to support accurate crude protein estimation across diverse matrices including cereals, dairy products, animal feed, soil extracts, pharmaceutical excipients, and industrial chemicals.

Key Features

• Engineered semi-automatic workflow: Independent control of alkali addition and steam distillation allows flexible method adaptation without cross-interference between steps.
• Digital timer with countdown display and audible end-of-cycle alert ensures precise process timing and operator awareness.
• High-sensitivity water-level probe in the steam generator maintains consistent steam output and prevents dry-heating incidents.
• Chemically resistant, one-piece molded anti-splash tube constructed from advanced acid/alkali-stable polymer ensures long-term gas-tight integrity and eliminates seal degradation.
• Front-access safety door with smooth slide mechanism enhances operator protection during condensate handling and receiver replacement.
• Energy- and water-efficient design includes automatic steam cutoff after preset time and low-flow condenser operation—aligned with ISO 14001-aligned lab sustainability practices.
• Non-corrosive ABS engineering plastic chassis provides mechanical stability, chemical resistance, and extended service life in humid or reagent-exposed environments.
• Parameter auto-memory function retains last-used settings—including alkali volume, distillation duration, and sample type—reducing setup time for repeat analyses.

Sample Compatibility & Compliance

The KDN-380F accommodates solid samples weighing 0.3–8.0 g and liquid samples ranging from 2.0–30.0 mL, supporting heterogeneous matrices such as ground grain, homogenized tissue, digested wastewater sludge, and viscous fermentation broths. Its validated recovery rate of ≥99.5% meets AOAC and ISO requirements for nitrogen determination accuracy. The system complies with GLP documentation principles through traceable manual parameter entry and observable process indicators (e.g., real-time timer, visual steam flow confirmation). While not equipped with electronic audit trails or 21 CFR Part 11-compliant software, its operational transparency supports manual record-keeping aligned with ISO/IEC 17025 internal quality assurance protocols.

Software & Data Management

The KDN-380F operates via embedded digital logic circuitry with no external PC dependency. All parameters—including alkali dosage, distillation duration, and start/stop sequencing—are configured using front-panel push-button controls and displayed on a high-contrast LED interface. No proprietary software, drivers, or cloud connectivity are required. Data output remains analog: final titration volumes are recorded manually into laboratory notebooks or LIMS-compatible spreadsheets. This architecture minimizes validation complexity for regulated environments where deterministic, non-updatable firmware is preferred over configurable software platforms.

Applications

This instrument serves laboratories performing standardized nitrogen quantification for regulatory reporting, quality control, and research applications. Primary use cases include crude protein calculation in agricultural commodities (per AOAC 981.10), nitrogen balance studies in nutritional science, compliance testing of fertilizer nitrogen content (ISO 5315), residual nitrogen screening in pharmaceutical intermediates, and environmental monitoring of total Kjeldahl nitrogen (TKN) in wastewater per EPA Method 351.2. Its adaptability to alternative distillations—such as cyanide liberation (ISO 6439), phenol extraction (ISO 6438), or sulfide release—further extends utility beyond classical nitrogen analysis.

FAQ

What digestion system is compatible with the KDN-380F?
The KDN-380F is designed exclusively for post-digestion distillation and requires prior sample mineralization using a separate Kjeldahl digestion block or microwave system.
Can the instrument perform direct steam distillation without digestion?
Yes—it supports direct distillation mode for analytes like free ammonia, cyanide, or volatile phenols when appropriate pre-treatment is applied.
Is the distillation time adjustable per sample?
Yes—users can set the distillation duration between 5 and 8 minutes via the digital timer, with automatic termination and audible notification.
Does the unit include titration accessories?
No—the KDN-380F delivers distillate to a standard receiving flask; titration reagents, burettes, and indicators must be supplied separately.
What maintenance is required for long-term reliability?
Routine cleaning of the condenser, anti-splash tube, and alkali reservoir is recommended after every 20–30 runs; steam generator descaling is advised quarterly in hard-water regions.