Sartorius YDK01 Mode D'emploi page 16

Adhesion of Liquid to the Wire
When the sample holder (or sieve) is
immersed in liquid causing buoyancy,
liquid travels up the wire because
of adhesion forces and generates an
additional weight in the range of
a few milligrams.
Since the sample holder (or sieve) is in
the liquid causing buoyancy during
both weighing in air and weighing in
liquid, and the balance is tared at the
beginning of each measuring procedure,
the effect of the meniscus can be
disregarded.
To reduce the surface tension and the
friction of liquid on the wire, add three
drops of a tenside (Mirasol Antistatic
or an ordinary dishwashing detergent)
to the distilled water in the beaker.
Because of the liquid travelling up the
wire, the weight may slowly change
even after the stability symbol "g"
appears. Therefore, read off the weight
immediately after the "g" is displayed.
16
Air Bubbles
The measuring error caused by air
bubbles adhering to the sample can
be estimated in the following manner.
An air bubble with a diameter of 0.5 mm
causes an additional buoyancy of less
than 0.1 mg when a sample is weighed
in water. An air bubble diameter of
1 mm causes additional buoyancy
of 0.5 mg and an air bubble diameter of
2 mm causes approx. 4.2 mg additional
buoyancy. Larger air bubbles must be
removed with a fine brush or other
utensil.
You can also wet the sample in a sepa-
rate container before you weigh it.