Why digital Instruments are better
An optical Abbe Refractometer and a set of hydrometers or a pycnometer belonged or still belong to the standard equipment of more or less every QC lab. Both the density and the refractive index depend on the temperature. For this reason, one or several thermostats (water baths) formed part of the inventory of most of the labs where densities and refractive indices had to be determined. A density measurement with a pycnometer is much more time consuming than a determination of the refractive index by means of an optical Abbe refractometer. This is probably the main reason why refractometry is still more popular in the quality control of liquid samples than density measurements.
The availability of highly accurate digital instruments for the determination of the density and the refractive index made the determination of these two parameters even more popular in the quality control of liquids. The reasons for this are clear:
• Higher accuracy of the results.
• Fewer error sources i.e. less operator
• Less time required for the measurements.
• No water bath required. Most of the digital
bench top instruments available nowadays
have a built-in Peltier thermostat, while portable instruments often have an
automatic temperature compensation.
• Direct display of the result in the desired unit. Modern digital instruments are able
to display concentrations directly and to do special temperature compensation of
the results if required. Measurement data may be printed out or archived in a
• Naturally the bench top and portable density meters and refractometers from
METTLER TOLEDO offer all these advantages.
With our latest offering, the combined determination of the density and the refractive index have become even easier.
The fact that density and refractive index measurements are being used more and more for the quality control of liquid samples has led METTLER TOLEDO to introduce the DR40/45 Combined Meters, instruments that determines both quantities simultaneously.
With the new sample delivery and cleaning units, SC1 and SC30, our density meters, refractometers and Combined Meters perform the measurements at a touch of a button.
These SC units are not only the best guarantee for fast payback of the equipment, they also help to prevent measurement errors and to reduce the consumption of cleaning solutions.