Selector · Kjeldahl line
Which Kjeldahl analyzer fits your lab?
Three questions — workload, automation, data compliance — narrow six models to one recommendation. The full comparison table is right below if you prefer to read, not click.
In short: low volume with a technician present → K1301/K1305; routine single-sample automation → K06/K1306; unattended batches of 20–35 → K12 with an A20/A35 autosampler; maximum accuracy plus audit-trail, LIMS-ready data → K18.
Answer three questions.
The K-series, side by side.
| Model | Automation | Recovery | Repeatability | Time / sample | Autosampler | Data software | Best for |
|---|---|---|---|---|---|---|---|
| K1301 | Semi-automated distillation | ≥99% | 1% RSD | 5–7 min | — | — | Entry labs with low daily volume |
| K1305 | Automated distillation | ≥99.5% | 1% RSD | 5–7 min | — | — | Distillation automation, titration off-line |
| K06 | Fully automatic (built-in titrator) | ≥99.5% | ≤0.5% | 3–8 min | — | 100,000 data sets, printer | Routine single-sample automation |
| K1306 | Fully automatic | ≥99.5% | ≤0.5% | 3–8 min | — | — | Fully automatic, broad industry use |
| K12 | Fully automatic | ≥99.5% | ≤0.5% | 3–7 min | A20 / A35 | User-defined schemes | Daily batches, unattended runs of 20–35 |
| K18 | Fully automatic flagship | ≥99.8% | ≤0.2% | 3–7 min | A20 / A35 | Audit trail, 5-level mgmt, LIMS | Highest accuracy plus compliant data management |
Batch workflows start upstream: the Smart 20 digester finishes twenty samples in one rack, and the whole rack transfers directly onto the A20 autosampler — no tube-by-tube handling. Method background: what is Kjeldahl analysis? · Buying logic in depth: the Kjeldahl buyer's guide.
Selection FAQ.
Which Sonnen Kjeldahl analyzer is best for high-throughput labs?
The K12 or K18 paired with an autosampler — the A20 (20-position rack, whole-rack transfer from the Smart 20 digester) or the A35 (35-position carousel) — runs 20–35 samples as a continuous unattended batch. Choose the K18 when you also need audit-trail data software with LIMS connectivity.
What is the difference between the K12 and the K18?
Both are fully automatic and autosampler-ready (A20/A35). The K18 covers everything the K12 does and adds a higher verified recovery (≥99.8% vs ≥99.5%), tighter repeatability (≤0.2% vs ≤0.5%), and a data package with audit trail, five-level user management and LIMS connectivity.
Which model fits a small lab running a few samples per day?
The K1301 or K1305: distillation is automated and titration is completed off-line, which keeps the investment low while a technician is present anyway. When daily volume grows, the fully automatic K06 is the natural upgrade.
Do all models cover the same measuring range?
Yes — every K-series model covers 0.1–240 mg N, from trace fertilizer work to high-protein dairy, with sample sizes up to 6 g solid or 25 mL liquid.
Tell us your sample type and daily load.
An application engineer maps it to a model within 24 hours.