VELP UDK139 Semi-Automatic Kjeldahl Distillation System

Overview

The VELP UDK139 Semi-Automatic Kjeldahl Distillation System is a precision-engineered platform designed for reliable, reproducible nitrogen determination via the classical Kjeldahl method. It operates on the fundamental principle of alkaline distillation: after digestion, ammonium salts in the sample are converted to ammonia gas under strongly basic conditions (NaOH), liberated by controlled steam injection, and subsequently trapped in boric acid for titrimetric quantification. The UDK139 integrates robust mechanical architecture with intelligent automation—enabling consistent steam generation, programmable reagent dosing, and real-time safety monitoring—while maintaining full compliance with internationally recognized standard methods including ISO 8968, AOAC 981.10, ASTM D1142, and USP . Its design prioritizes operator safety, analytical traceability, and long-term operational stability in high-throughput laboratory environments across food, feed, environmental, pharmaceutical, and chemical sectors.

Key Features

• 3.5-inch full-color touchscreen interface with intuitive navigation and multi-language support (including English, German, French, Spanish, and Chinese)
• Automated reagent delivery system featuring high-accuracy peristaltic pumps for precise, repeatable addition of NaOH (0–150 mL) and distilled water (0–200 mL)
• Adjustable steam generator with continuous output control from 10% to 100%, enabling optimized distillation kinetics for diverse sample matrices
• Titanium-coated condenser offering superior thermal efficiency and exceptional resistance to caustic corrosion during prolonged operation
• Patented anti-splash boiling tube with reinforced geometry to minimize foaming, prevent carryover, and ensure quantitative ammonia recovery
• Comprehensive safety architecture: tube presence detection, interlocked safety door sensor, alkali container guard rod, waste tray level switch, condensate flow monitor, and real-time reagent volume tracking—all triggering audible/visual alerts upon anomaly
• Corrosion-resistant polymer housing engineered for durability in aggressive laboratory environments containing alkaline vapors and condensates

Sample Compatibility & Compliance

The UDK139 accommodates standard 100–500 mL Kjeldahl digestion tubes and supports both macro- and semi-micro Kjeldahl configurations. It is validated for total Kjeldahl nitrogen (TKN), protein estimation (using standard conversion factors), volatile basic nitrogen (TVBN), ammoniacal nitrogen, and Devarda-reducible nitrogen. Method compliance extends to ISO 5983-1/2 (animal feeding stuffs), ISO 1871 (cereals), EPA Method 351.2 (wastewater), and pharmacopeial procedures requiring nitrogen content verification (e.g., USP monographs for amino acids and peptides). All critical process parameters—including steam duration, reagent volumes, and distillation timing—are logged and exportable, supporting GLP/GMP documentation requirements and internal audit readiness.

Software & Data Management

The embedded firmware enables storage and execution of up to 10 user-defined analytical protocols, each configurable for individual sample types, digestion outcomes, and regulatory reporting needs. Process data—including start/stop timestamps, reagent volumes dispensed, steam intensity profiles, and safety event logs—are timestamped and retained locally. Export is supported via dual USB ports (for flash drive data transfer or peripheral integration), with CSV-formatted reports compatible with LIMS and ELN systems. While the UDK139 does not include built-in electronic signature or 21 CFR Part 11 compliance modules, its deterministic behavior, audit-ready event logging, and parameter traceability facilitate integration into validated workflows under FDA, EMA, or MHRA oversight when paired with appropriate laboratory informatics infrastructure.

Applications

• Food & Feed Analysis: Routine TKN and crude protein quantification in dairy, meat, cereals, soy, and pet food; TVBN assessment for seafood freshness; alcohol content determination via distillative separation
• Environmental & Agricultural Testing: Total nitrogen in soils, sludge, wastewater, and plant tissues; COD pre-treatment support; phenol and ammonia analysis in surface and groundwater
• Pharmaceutical & Chemical R&D: Nitrogen content verification in APIs, excipients, and polymers; ammonium salt quantification in synthesis intermediates; quality control of nitrogen-containing catalysts and reagents

FAQ

What standards does the UDK139 comply with for nitrogen analysis?
The system adheres to ISO 8968, AOAC 981.10, ASTM D1142, and USP , with method-specific validation achievable through instrument qualification protocols.
Can the UDK139 be integrated into a fully automated Kjeldahl workflow?
Yes—it is compatible with VELP’s SER 15.8 digestion units and optional autosamplers, enabling unattended digestion-to-distillation sequences when configured with appropriate interface modules.
Is the titanium condenser serviceable or replaceable?
The titanium-coated condenser is field-replaceable using standard VELP service kits; routine maintenance includes descaling with dilute citric acid and visual inspection for coating integrity.
Does the UDK139 support remote diagnostics or network connectivity?
No native Ethernet or Wi-Fi capability is included; however, USB-based data extraction and external PC synchronization allow for centralized instrument performance review and preventive maintenance scheduling.
What is the expected service life of the peristaltic reagent pump tubing?
Under typical usage (≤100 analyses/day), fluoropolymer-reinforced tubing maintains volumetric accuracy for ≥6 months; replacement intervals are tracked via the onboard maintenance log.