Kjeldahl distillation system - KjelMaster K-375

Measuring range: 0.02–220 mg N
Adjustable steam output: 30–100%
Recovery: >99.5% (1–200 mg N)
Reproducibility (RSD): <1%
Titration: potentiometric (pH), colorimetric, back titration (pH)
Online titration: yes – started already during distillation
Smart distillation (IntelliDist): yes – automatic detection of operating temperature, no preheating required
Display: 8.4" color touch screen
Result memory: >100,000 on instrument, unlimited with KjelLink
Autosampler: optional KjelSampler K-376 (24 positions) / K-377 (48 positions)
Compatible sample tubes: 100, 300, and 500 mL
Sample parameters: Total Kjeldahl Nitrogen (TKN), Total Volatile Basic Nitrogen (TVBN), nitrate, nitrite
Dimensions (W × D × H): 458 × 431 × 670 mm
Weight: 32 kg
Power consumption (during distillation): 2,400 W

The KjelMaster K-375 distillation unit is the flagship of the BÜCHI Kjeldahl system range. It delivers high throughput and full automation of the entire analytical process from distillation to titration.

Integrated titrator with precise detection

The K-375 features a built-in titrator. The instrument is available in two configurations – with colorimetric detection (Optrode optical sensor) or potentiometric detection (pH electrode). The choice of configuration depends on the sample matrix and the requirements of the specific application. Both variants also support back titration for specialized analyses. Switching to the alternative detection method is possible by purchasing the corresponding accessory kit.

High performance and automation

The K-375 processes samples within a measuring range of 0.02–220 mg N with a recovery of over 99.5%. The online titration function starts the measurement already during distillation, reducing the overall time to result. The smart distillation mode IntelliDist automatically detects the operating temperature and eliminates the need for preheating.

Intuitive operation and data management

The instrument is equipped with an 8.4" color touch screen featuring an easy-to-use interface. The internal memory stores more than 100,000 results. KjelLink PC software provides bidirectional data exchange, LIMS connectivity, and full result traceability. An optional firmware package for CFR 21 Part 11 compliance adds audit trail functionality and electronic signatures.

Upgrade to a high-throughput system

For maximum sample capacity, the K-375 can be combined with the KjelSampler K-376 (24 positions) or K-377 (48 positions). Sample transfer from the autosampler to the distillation unit is carried out by steam overpressure – no sample tube cleaning or glass transfer is necessary. Two independent racks on the K-377 enable a continuous batch workflow. The express rack allows priority processing of blanks and reference samples.

Convenient and safe

All handling of reagents is fully automated – eliminating any contact between the user and harmful chemicals. Three safety sensors (service door, protecting door, sample tube) ensure safe operation. The compact bench top design saves valuable laboratory space.

Compatibility and accessories

The system is compatible with all BÜCHI sample tubes (100, 300, and 500 mL) and can be combined with the KjelDigester K-446/K-449, balances, printers, barcode readers, and the Recirculating Chiller F-314.

Cost pet Analysis Claculator

Discover our Kjeldahl Cost per Analysis Calculator – a practical tool for calculating and comparing analysis costs, including Micro Kjeldahl and back titration, with PDF export.