Freezing point osmometer

for the determination of osmolality or freezing point of aqueous solutions

KNAUER is one of the pioneers in the field of osmometry and known for its reliable and user-friendly instruments for many decades.

Freezing point osmometer K-7400S allows the easy and fast determination of the osmolality of various aqueous solutions. Also, the freezing point depression of the samples can be read. The proven technology of freezing point determination in combination with the robust and intelligent design of the device allows reproducible measurements. The instrument is equipped with a peltier cooler and an integrated microprocessor controlling the automated measurement.

The freezing point osmometer is a standalone device that optionally can be equipped with a printer. Furthermore, the device can be controlled via the EuroOsmo 7400 software. The software automatically plots the temperature curve for each measurement and calibration and allows saving of the measured values. In addition, the data can optionally be exported into various file formats for archival storage.

The measurement specifications of the KNAUER Semi-Micro Osmometer K-7400S comply with the requirements of the European Pharmacopoeia for osmolality (Ph. Eur. 2.2.35, 10/2021) in the pharmaceutically relevant range of 0-400 mOsmol/kg.

Freezing point osmometer


Sample volume 50 – 150 µl
Osmolality range 0 – 2000 mOsmol/kg
Resolution osmolality: integer value without decimal part, e.g. 850 mOsmol
temperature: value with three digits, e.g. -1.576 °C
Test time ~ 2 min
Precision SD ≤ 4 mOsmol/kg [0 — 400 mOsmol/kg]
RSD ≤ 1 % [400 — 2000 mOsmol/kg]
Linearity ± 1 % [0 -1500 mOsmol/kg]
± 1.5 % [0 – 2000 mOsmol/kg]
Calibration Two-point calibration (0 mOsmol/kg and one freely selectable osmolality)
optional: Three-point calibration (0 Osmol/kg and two freely selectable osmolalities)


Power supply 100 – 240 V, 50 – 60 Hz, 70 W
Dimensions 160 x 182 x 340 mm (W xH x D)
Weight 5.3 kg
Ambient conditions Temperature range: 10–35 °C
Rel. humidity: 20–80 % (non-condensing)


Interfaces RS-232 port
Control Keypad (LED display, 2 rows with 24 characters)
optional: EuroOsmo7400 Software

System Components

Upgrade Kit for K-7400

Upgrade Kit for K-7400

required to use measuring head for sample tubes
Datalogic Barcode Scanner

Datalogic Barcode Scanner

It is intended to use the scan function implemented in the EuroOsmo 7400 software
EuroOsmo 7400

EuroOsmo 7400

a user-friendly software developed for the freezing point Osmometers K-7400 and K-7400S
Measuring head

Measuring head

for plastic sample tubes; compatible with the K-7400 and the K-7400S Semi-Micro Osmometer
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