VELP UDK129 Semi-Automatic Kjeldahl Nitrogen Determination System

Overview

The VELP UDK129 Semi-Automatic Kjeldahl Nitrogen Determination System is a precision-engineered distillation unit designed for reliable and reproducible total nitrogen quantification in accordance with standardized Kjeldahl methodology (ISO 8968, AOAC 984.13, ASTM D1122, USP , and EN ISO 1871). It implements classical wet digestion–distillation–titration workflow, where nitrogen-containing samples are first digested in concentrated sulfuric acid, followed by alkaline distillation to liberate ammonia, which is then trapped in boric acid and quantified via titration. The UDK129 serves as the critical distillation module in this sequence—optimized for high throughput, operator safety, and long-term stability in routine QC/QA laboratories across food, feed, environmental, and agricultural testing sectors.

Key Features

• Corrosion-resistant polymer housing engineered for extended service life in aggressive chemical environments, including repeated exposure to concentrated NaOH and H₂SO₄ vapors.
• Patented steam generator system ensuring consistent, controllable vapor pressure and thermal stability during distillation cycles—eliminating fluctuations that compromise recovery accuracy.
• Titanium condenser assembly (patent-pending) delivering superior thermal conductivity and corrosion resistance compared to conventional glass or stainless-steel alternatives; enables efficient heat exchange without external chillers, even under ambient temperatures up to 30°C.
• Integrated peristaltic reagent pump with programmable dosing (0–100 mL NaOH), calibrated for volumetric precision and minimizing operator intervention.
• Digital LCD interface supporting user-defined method storage, real-time display of distillation progress, reaction timing, and status alerts—designed for intuitive operation and audit-ready traceability.
• High-performance polymer anti-splash ball trap resistant to alkali-induced etching, reducing carryover risk and improving measurement fidelity, particularly for high-fat or viscous matrices.
• Energy-optimized cooling architecture: water consumption reduced to 0.5 L/min at 15°C ambient, enabling lower operational costs and compatibility with decentralized lab infrastructure.

Sample Compatibility & Compliance

The UDK129 accommodates a broad range of solid and liquid samples following standard Kjeldahl digestion protocols—including cereals, dairy products, meat, fertilizers, wastewater sludge, and soil extracts. Its robust construction meets IP20 electrical safety classification and complies with CE marking requirements under the EU Machinery Directive 2006/42/EC and Low Voltage Directive 2014/35/EU. Method validation data confirm adherence to ISO 5725-2 (repeatability ≤1% RSD) and ISO 14253-1 (measurement uncertainty management). When integrated into validated laboratory workflows, the system supports GLP and GMP documentation practices, including electronic record retention for reagent volumes, distillation durations, and operator IDs—facilitating 21 CFR Part 11 readiness when paired with compliant LIMS or titration software.

Software & Data Management

While the UDK129 operates as a standalone distillation unit, its digital control architecture supports seamless integration with external titration systems (e.g., Metrohm 905 Titrando, Hanna HI84532) via RS232 or analog output signals. All method parameters—including NaOH volume, distillation time, and delay intervals—are stored in non-volatile memory and timestamped upon execution. Optional VELP KjelMaster™ software (sold separately) provides centralized method deployment, instrument fleet monitoring, and export of CSV-formatted logs compatible with Excel, LabWare LIMS, or Empower CDS. Audit trails include operator login, parameter changes, and cycle completion events—enabling full traceability for internal audits or regulatory inspections.

Applications

• Protein content determination in food and feed (conversion factor 6.25 applied to %N)
• Crude protein analysis in animal nutrition formulations and aquaculture feeds
• Nitrogen balance studies in agronomic research and fertilizer efficacy trials
• Wastewater treatment plant monitoring (TKN, ammoniacal nitrogen)
• Soil nutrient profiling and compost maturity assessment
• Pharmaceutical excipient qualification per USP and Ph. Eur. 2.5.20

FAQ

What digestion units are compatible with the UDK129?
The UDK129 is designed to interface with all standard Kjeldahl digestion blocks and auto-digesters meeting ISO 8968-1 mechanical coupling specifications—including VELP’s own DK series and third-party systems with 40 mm tube spacing.
Does the titanium condenser require special maintenance or cleaning protocols?
No. Unlike glass condensers, the titanium assembly is inert to caustic solutions and does not require periodic descaling or replacement; routine rinsing with deionized water post-use is sufficient.
Can the UDK129 be used for direct distillation without prior digestion?
No. The UDK129 performs only the distillation step. Sample digestion must be completed externally using certified Kjeldahl digestion equipment before loading into the distillation unit.
Is cold water recirculation supported?
Yes—the system accepts chilled water input (down to 5°C) and maintains optimal condensation efficiency across the full specified flow range; however, external chillers are not required for nominal operation.
How is method validation documented for regulatory submissions?
VELP provides IQ/OQ documentation templates aligned with ISO/IEC 17025 and FDA guidance; users retain responsibility for PQ execution under their site-specific SOPs, with UDK129 contributing raw distillation data for inclusion in validation reports.