DEN-1, Densitometer (suspension turbidity detector)


Densitometer is designed for measurement of cell suspension's turbidity in the range of 0.3–5.0 McFarland units (100×106 – 150×107 cells/ml).

Densitometer provides the opportunity to measure solution turbidity in a wider range (up to 15.0 McFarland units) however, it is necessary to remember that in this case the standard deviation values increase.

A densitometer is used for measurement of cell concentration (bacterial, yeast cells) during fermentation process, determination of microorganism sensitivity to antibiotics, microorganism identification using various test-systems, for measurement of absorption at the definite wavelength, as well as for quantitative estimation of concentration of colour solution, absorbing green light.

The operation principle is based on measurement of optical density with digital presentation of  results in McFarland units. The unit is calibrated at the factory (for operation with 16 mm diameter glass tubes) and keeps calibration without power supply. However, if necessary it is possible to calibrate the unit by 2–6 points in 0.5–5.0 McFarland unit range. We recommend to use Biosan standards to ensure full reliability, but it is acceptable to use other commercial as well as self prepared standards (e.g. BaSO4). Possibility to restore factory calibration settings*

Following calibration kits are available on request:

  • CKG16 for glass tubes with diameter 16 mm set of 0.5; 1.0; 2.0; 3.0; 4.0 McFarland

Two versions of the product are available:

  1. DEN-1 powered from external energy supply;
  2. DEN-1B powered both from external energy supply and from batteries (АА). Besides, DEN-1B operates with higher precision of measurements (up to 0,01 McF).



Light source LED
Measurement wavelength (λ) λ = 565 ±15 nm
Measurement range 0.3–15.0 McF
Display resolution 0.1 McF
Accuracy (0.3–5.0 McF) ±3%
Measurement time 1 s
Sample volume not less than 2 ml
Tube external diameter 16 mm (using A-16 adapter) or 18 mm (without adapter)
Possibility to restore factory calibration settings +
Display LED
Overall dimensions (W×D×H) 165 × 115 × 75 mm
Weight 0.7 kg
Input current/power consumption 12 V, 80 mA / 1 W
External power supply Input AC 100–240 V, 50/60 Hz; Output DC 12 V
Standard set External power supply, A-16 adapter for ø16mm tubes

Cat. Nr.

DEN-1 incl. A-16 adapter, external power supply unit
BS-050102-AAF 230VAC 50/60Hz Euro plug
BS-050102-AAK 230VAC 50/60Hz UK plug
BS-050102-AAK 230VAC 50/60Hz AU plug
BS-050102-AAK 100VAC 50/60Hz US plug
BS-050102-AAK 120VAC 60Hz US plug
---------------- Optional accessories
BS-050102-BK CKG16 - ø16mm - 0.5; 1.0; 2.0; 3.0; 4.0 McF
BS-050102-LK Glass sample tubes without lid (16х100x0.8mm), 78 pcs. Fits DEN-1, DEN-1B factory calibrated.
BS-050102-DK IQ OQ document
BS-050102-EK PQ document
---------------- Replacement parts
BS-050102-AK A-16, adapter for 16 mm tubes

Frequently asked questions

Can I use tubes of different diameter?

Yes. Glass and transparent plastic tubes (16 or 18 mm in external diameter) can be used for work with DEN-1 densitometer. A-16 adapter (included) must be used for work with tubes which are 16 mm in external diameter.

Note! The unit must be calibrated every time a tube type (e.g. with different ext. diameter, bottom shape or different material) is changed.

Can standards prepared in the laboratory be used for calibration?

Yes. Both commercial standards and standards prepared in the laboratory can be used for calibration.

For what type of tubes is DEN-1/DEN-1B precalibrated at the factory?

From December 2015 factory calibration is for work with glass tubes with an external dimeter of 16 mm

How to caibrate DEN-1/DEN-1B?

Calibration procedure is described in the user manual p.3.4. See user manual below.

How to restore factory calibration settings?

Procedure of restoration of factory calibration settings is described in the user manual p 3.5. See user manual below.