LimsPulse
Food & proximate analysis

Kjeldahl digestion & distillation unit

Digests a food sample in hot sulphuric acid to turn its organic nitrogen into ammonium, then distils the ammonia and titrates it. The nitrogen found, multiplied by a conversion factor, gives crude protein.

  • Food & beverage
  • Dairy
  • Animal feed
  • Agriculture
  • Environmental
  • Fertiliser
Photo of a Kjeldahl digestion & distillation unit
Photo: Giancarlo Dessì, CC BY-SA 3.0 (cropped), via Wikimedia Commons
CALIBRATION

Kjeldahl calibration procedures

Nitrogen recovery check

Confirms that the distillation unit recovers all the ammonia (ammonium sulphate) and that digestion plus distillation recovers all the organic nitrogen (tryptophan or acetanilide).

Open procedure

Digestion block temperature

Checks that the digestion block reaches its set temperature and that all tube positions are heated evenly.

Open procedure
QUALIFICATION

Instrument qualification (DQ · IQ · OQ · PQ)

  1. 01

    DQ — Design qualification

    Defines the needs: number of tubes, maximum block temperature, scrubber type, automatic or manual titration, software and data records.

  2. 02

    IQ — Installation qualification

    Confirms the units, utilities (power, cooling water, drain, exhaust), tubing and software are installed as specified, with serial numbers and manuals recorded.

  3. 03

    OQ — Operational qualification

    Checks block temperature accuracy and uniformity, alkali and water dosing, steam generation and titrator function against specifications.

  4. 04

    PQ — Performance qualification

    Shows the system gives correct results in routine use, for example nitrogen recovery with ammonium sulphate and an organic standard, plus a food reference material.

In LimsPulse · Calibration Management

Keep every Kjeldahl in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how