The KD‑310CN Distillation‑Titration Integrated Unit is Goodwill highest‑accuracy fully‑automatic Kjeldahl nitrogen analyzer. This new KD‑310CN distillation instrument delivers fully‑automated operation, meeting laboratory requirements for continuous‑run workflows, high repeatability and stringent safety standards. It features inline distillation‑titration: titration proceeds simultaneously with distillation and completes the moment distillation finishes.

It is equipped with a delayed‑distillation function. By adjusting reagent‑adding sequences, the instrument automatically adds water to dilute digested samples, then introduces steam for a short period to agitate samples. This facilitates dissolution of caked digested residues and dilution of concentrated sulfuric acid. Sodium hydroxide is added afterwards to mitigate violent acid‑base reactions. The delay time for delayed distillation is continuously adjustable and programmable. Real‑time monitoring of effluent temperature guarantees accurate and reliable analytical results.

High‑Precision Titration System

It adopts colorimetric titration complying fully with standards published by AOAC, IDF, ISO and other authorities. Its unique titration system features pre‑titration technology to reduce relative errors for more precise results. The standard‑configured 50 mL burette eliminates the need to switch titrant acid concentrations when analyzing samples with vastly different protein contents.

• 1- The exclusive pre‑titration method reduces relative standard deviation and simplifies switching between different standard acid solutions.
• 2- The 50 mL burette with auto‑refill enables a broad analytical range and shortens analysis duration.
• 3- 1.95 μL per‑step burette dispensing delivers unmatched precision.
• 4- Easily‑replaceable glass anti‑splash tip minimizes carry‑over effects.
• 5- PTFE‑lined standard acid tubing suppresses bubble formation during titration.
• 6- Data can be transmitted to nearly any wireless‑client‑enabled device including laptops, tablets and smartphones.
• 7- CSV‑formatted data can be imported directly into the instrument; direct computer‑to‑balance connection is supported.
• 8- Data can be effortlessly exported to spreadsheets, text editors or databases. Sample macro‑scripts automatically send and retrieve data from bundled spreadsheets to accommodate custom application needs.

Highly‑Adaptable Workflow

The instrument offers full flexibility to adapt to your requirements either by using existing laboratory protocols or built‑in instrument procedures, lowering integration costs.

• 1-Built‑in adaptable workflows keep full process control within reach. It supports rapid processing of samples without pre‑entered weight values. Sample weights can be entered via touch‑screen or external devices with any valid connection combination.
• 2- Custom workflows can be defined on the touch‑screen. Users may personalise result formats, analytical methods and analysis sequences to streamline daily laboratory routines.
• 3- Multi‑level access permissions and menus are available in compliance with GLP requirements. Dedicated menus grant laboratory administrators advanced configuration such as burette validation, titration endpoint setup, factory default restoration, date & time settings.
• 4- Comprehensive user‑maintenance functions are embedded. Sensors detect sample‑tube placement and safety‑door status. Interlocked safety doors trigger full instrument shutdown if doors remain unclosed or are accidentally opened. Automatic sample‑tube draining removes risks of operator contact with hot post‑distillation solvents.

ISO 17025‑Compliant Operation

Traceable data files, QR‑code technology and multi‑tier user access simplify ISO 17025‑compliant implementation. The Apparent‑Performance Traceability System alerts operators if analytical results drift over time.

• 1- The Apparent‑Performance Traceability System delivers ongoing real‑time result validation. Standard reagents of known nitrogen content track instrument performance across time. All records are stored in an independent log file for easy wireless export to computers. Warnings are triggered once analytical‑result deviations occur.
• 2- The component‑traceability programme tracks hardware components and allows service engineers to retrieve service‑life status of key modules.
• 3- User‑IDs are logged alongside sample‑weight inputs and analytical results for full event traceability. Data integrity and traceability are preserved during bidirectional data transfer between instrument and computer.
• 4- Dedicated administration menus support QC operations such as burette performance tests.

Maintenance Programme

Diagnostic and component‑tracking capabilities greatly minimise instrument downtime for end‑users and service engineers. Real‑time monitoring covers component operational status, sensor response sensitivity and protective‑device actuation status.

Technical Specifications

• 1 Analytical principle: Concentrated sulfuric acid digestion, alkaline‑environment steam distillation, boric‑acid absorption, color‑indicator titration endpoint determination.
• 2 Recovery rate: ≥99.5%.
• 3 Test precision: ≤±0.5% RSD. Unique pre‑titration technology reduces relative standard deviation.
• 4 Measuring range: 0.05‑240 mg nitrogen.
• 5 Built‑in titration unit: Color‑based endpoint judgment complying with AOAC and GB standards.
• 6 Titration resolution: 1.95 μL/step — 0.8 μL/step.
• 7 Standard‑acid burette: 50 mL large‑capacity burette. No titrant‑acid replacement required for samples with low‑to‑high nitrogen content.
• 8 Titration system adopts positive‑pressure delivery. Standard acid is stored in the upper section of the titration unit to eliminate bubble‑related interferences.
• 9 Steam intensity adjustment range: 10‑100%. Maintenance‑free stainless‑steel steam generator.
• 10 Fully programmable automatic workflows: automatic water dilution, alkali addition, boric‑acid dosing, distillation, titration and calculation.
• 11 Automatic waste‑liquid discharge: automatic draining of digestion‑tube waste and receiving‑cup titration waste; automatic receiving‑cup cleaning function.
• 12 Automatic data storage, data transmission and print functions.
• 13 Multiple safety protections: digestion‑tube‑in‑place detection, safety‑door status monitoring, steam‑generator over‑temperature / over‑pressure / liquid‑level protection, cooling‑water monitoring, digestion‑tube replacement detection, titration‑end‑point liquid‑level monitoring and other protective functions.
• 14 Optional four liquid‑level sensors: automatic alarms for shortage of alkali, water or boric acid, and full‑waste‑barrel alert.
• 15 Coated anti‑splash protector with service life of over five years.
• 16※  7‑inch color touch‑screen for the fully‑automatic distillation unit; programmable analytical procedures (including delayed distillation and steam‑balanced reagent‑addition modes).
• 17 Flexible wireless‑communication system with open‑format data exchange. CSV‑format data can be exported directly to computers, tablets, smartphones and other wireless‑client‑enabled devices. Direct computer‑to‑balance connection is supported.
• 18 Advanced Apparent‑Performance Traceability System: standard reagents with known nitrogen content continuously track instrument performance over time. All records are saved in an independent log file for easy wireless export to computers. Alarms are triggered when analytical‑result drift occurs.
• 19 Advanced maintenance functions. The component‑traceability programme tracks service life of internal hardware via instrument log files and recommends component replacement prior to potential failures. Remote‑control software is available for maintenance operations.
• 20 Traceable data files, QR‑code technology and multi‑level user‑access controls for full ISO 17025 compliance.