Description & Specifications
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The Vapor Pressure Osmometer K-7000 from KNAUER is an advanced instrument from
one of the pioneers in the field of osmometry with more than 40 years of experience. It
stands out for its high performance, data quality and reliability. The Vapor Pressure Osmometer K-7000 is best suited for : • Molecular weight determination up to 40 000 g/mol • Determination of total osmolalities of physiological fluids The Vapor Pressure Osmometer measurement principle is based on vapor pressure reduction in
solutions corresponding to Raoult’s law. Two identical thermistors are located in a cell where
the gas phase is saturated with solvent vapor. If both thermistors carry drops of pure solvent,
the difference in potential between the two is zero. During measurement, one of the solvent
droplets is replaced with a drop of solution (with reduced vapor pressure). Now solvent vapor
will condense on the solution droplet and thus vapor pressure increases until it equals the
pressure of the pure solvent droplet. The increasing pressure leads to a rising temperature of the
solution droplet. This increase of temperature and the number of particles dissolved in the
solution are proportional. Thus, concentrations as well as molecular weights (if the
concentration is known) can be determined. The K-7000 requires only one set of thermistor probes to cover the entire temperature range
between 20° and 130°C for all types of aqueous and organic solvents, minimizing set-up times. The Vapor Pressure Osmometer K-7000 is easy to operate. In stand-alone mode all
measurement results can be reviewed on the internal display. If desired, a plotter can be
connected as well. KNAUER adds more value to the K-7000 with the external data evaluation software package
EuroOsmo®
. This option will enhance your productivity and make the evaluation of
experimental results faster and easier. The EuroOsmo®
7000 software can be used to control all measurement settings (e.g.
temperature and detection time). Molecular weights and osmolalities are directly determined
by the software from the measurement and calibration data. Technical data : Molecular weight range Aqueous: up to 10 000 g/mol; Organic: 40 – 40 000 g/mol Concentration range 1 x 10-3 – 15 molal Sensitivi 3.3 x 10-5 mol/kg in toluene; 1.7 x 10-4 mol/kg in water Min. sample volume approx. 10 µl (one drop) Sample capacity up to 4 samples Test time 1.5 – 5 Minutes per measurement Cell temperature range 20 – 130 °C ∆T Head thermostat 0 – 6 °C Warm-up time 5 – 40 °C, 0.5 h; 40 – 60°C, 1.0 h; 60 – 100°C, 1.5 h; 100 – 130°C, 2.0 h Syringes 1 ml, glass with Teflon®
/stainless steel piston |