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Family 01 / 10 · K1305 · K1306 · K06 · K12 · K18

Kjeldahl nitrogen & protein analyzers.

In short: Sonnen builds six Kjeldahl nitrogen analyzer lines: semi-automatic distillation units (K1305, K1301) and fully automatic distillation–titration systems (K06, K1306, K12, K18). Recovery is ≥99.5% in standard test mode, and K12/K18 reach ≥99.8% in high-nitrogen mode. K12 and K18 connect to the A20/A35 autosamplers for unattended 20/35-sample batch operation.

K12 fully automatic kjeldahl nitrogen analyzer on a laboratory bench

Automated distillation and distillation–titration systems built on the classic Kjeldahl method, with color-sensor end-point detection, ≥99.5% standard recovery (K12/K18 reach 99.8% in high-nitrogen test mode) and dedicated modules for nitric nitrogen and high-nitrogen samples. The K06, K1306, K12 and K18 run a complete single-sample test cycle unattended once started; the K12 and K18 add an autosampler interface for continuous 20/35-sample batch operation with the A20/A35.

Models in this family

K1305 automated kjeldahl nitrogen analyzer on a laboratory bench K1305 K1305 Automated Kjeldahl Nitrogen Analyzer, Kjeldahl Distillation Unit ≥99.5% · 0.1–240 mg N → K1301 semi-automated kjeldahl nitrogen analyzer on a laboratory bench K1301 K1301 Semi-Automated Kjeldahl Nitrogen Analyzer, Kjeldahl Distillation Unit ≥99% · 0.1–240 mg N → K1306 automatic kjeldahl nitrogen analyzer on a laboratory bench K1306 K1306 Fully Automated Kjeldahl Nitrogen Analyzer, Kjeldahl Distillation and Titration System ≥99.5% · 0.1 mg–240 mg N → K06 K06 Fully Automatic Kjeldahl Nitrogen Analyzer, Distillation and Titration System ≥99.5% · 0.1–240 mg N → K12 fully automatic kjeldahl nitrogen analyzer on a laboratory bench K12 K12 Fully Automated Kjeldahl Nitrogen Analyzer, Kjeldahl Distillation and Titration System ≥99.5% · 0.1–240 mg N → K18 fully automatic kjeldahl nitrogen analyzer on a laboratory bench K18 K18 Fully Automated Kjeldahl Nitrogen Analyzer, Kjeldahl Distillation and Titration System ≥99.8% · 0.1–240 mg N →

How to choose.

  • Single-sample unattended testing — the K06, K1306, K12 and K18 complete a full test cycle without an operator once started.
  • Unattended batch operation — K12/K18 pair with the A20 (20-position) or A35 (35-position) autosampler for continuous multi-sample runs.
  • High-nitrogen or nitric-nitrogen samples — dedicated modules on the K12/K18; recovery ≥99.8% in high-nitrogen test mode.
  • Data integrity & LIMS — the K18 adds five-level user management, audit trails and LIMS connectivity for regulated labs.
  • Distillation only — K1305/K1301 where titration is handled separately.

Three questions to the right model: 30-second Kjeldahl selector →

Related: The Kjeldahl method — pillar note · ISO 20483 (cereals & pulses) · ISO 8968 (milk & dairy) · Kjeldahl nitrogen analyzer buying guide

Frequently asked questions.

Which Sonnen analyzers support unattended batch testing?

The K12 and K18. Both have an autosampler interface and pair with the A20 (20-position rack-type) or A35 (35-position carousel) autosampler for continuous batch operation. The K06, K1306, K12 and K18 all run a complete single-sample test cycle unattended once started.

What recovery rate do Sonnen Kjeldahl analyzers achieve?

≥99.5% recovery in standard test mode across the K-series; the K12 and K18 reach ≥99.8% in high-nitrogen test mode, with repeatability RSD ≤0.2% on the K18.

Semi-automatic or fully automatic — what is the difference?

The K1305/K1301 automate distillation; the K06, K1306, K12 and K18 automate the complete distillation–titration cycle and calculate the result. Fully automatic models remove the separate titration step and the operator attention it requires.

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