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Nephelometer: Dosascat

Technical Description

Aimed at the analysis of protein, e.g. in CSF
Useful for many nephelometric determinations requiring high sensitivity

The nephelometer Dosascat has been aimed at the analysis of proteins.
The built-in programme for total protein allows a  sensitive determination of total protein. This determination is quite resistant against interferences. The method may be used for serum, urine, CSF, and other biochemical liquids.

Single proteins may be determined at low concentrations with immunoreaction in the nephelometer. This allows to do the complete protein analysis of CSF.

In many cases the instrument is used in addition to automatic nephelometers,  e.g. to determine the total protein concentration in order to save reagents.


Determination of total protein

The maximum of scattering is directly proportional
to the concentration of total protein

The nephelometric method of the determination of proteins allows to measure the concentration of the total protein in CSF.
As this method is quite resistant against interferences it can be also applied for the following liquids:

  • Urine
  • Serum; the method is resistant against plasmaexpanders like dextran;
  • other biochemical liquids; the method is resistant against biochemical reagents like detergents; urea and salts;
  • membrane proteins or other non water soluble proteins, which are solved in alkaline SDS-solution, may be measured directly.

A possible colour of the sample is of no importance, as the measurement is done comparing with the blank. Pipetting in the nephelometer is required only once. The method is quite resistant against interferences. The concentration refers to the real mass of protein, as this methoid does not depend of the ratio of aminoacids or the shape of the proteins.
The method is ideal for a fast determination of single samples, and does not compete with the Biuret-reaction, which is not sensitive enough for total protein at low concentrations.

The determination and handling is very simple:

  • reagent to be dispensed into the cuvette
  • insertion of cuvette with reagent into sample compartment
  • dispensing of sample into cuvette
  • readout of total protein concentraion

At the beginning a calibration with a protein standard is required.


Determination of Albumin, IgG, IgA and IgM and other proteins

Following the preparation of a standard curve the concentraiton ot the individual proteins may be read out.


Other nephelometric determinations

Due to the simple handling the instrument may be also used for other demanding nephelometric determinations. Whereas turbidimetry measures the difference between illumination and outgoing light, nephelometry or scattered light photometry measures the light scattered into an angle of typically 70° forward. Therefore already very small amounts of particles cause a signal, which is higher than in the case of tubridimetry. Therefore nephelometric determinations are especially useful for the determination of particles at low concentrations.


New optical system

To optimize sensitivity at low cost the optial system uses a new method, which has proven its efficiency in many tests.
instead of a narrow bandwidth a broad bandwidth has been chosen for the illumination. This results in a relatively high energy of illumination and -together with a very sensitive detector- assures a very high sensitivity.

Built-in magnetic stirrer for kinetic measurements

In order to ensure a fast and homogeneous mixing of the sample a magentic drive underneath the cuvette and a magnet in the cuevtte allow to stir the sample continuously. This is important e.g. in the case of a fast precipitation, like in the case of the determination of total protein.


Economic maintenance

The lamp exchange can be done easily. Open the lamp housing cover and replace lamp. No adjustment is required.
The sample compartment may be opened for cleaning, also the magnetic drive can be removed easily.


Low investment and consumable cost

Both investment for the instrument and consumables are very economically priced. Ask your local distributor for a quotation!