Xylem ProLab 1000 BENCH TOP pH METER - Manual (Page 89)

ProLab 1000 Lists
89 ba75576e04 01/2011
Glossary
Adjusting To manipulate a measuring system so that the relevant value (e. g. the
displayed value) differs as little as possible from the correct value or
a value that is regarded as correct, or that the difference remains
within the tolerance.
AutoRange Name of the automatic selection of the measuring range.
Calibration Comparing the value from a measuring system (e. g. the displayed
value) to the correct value or a value that is regarded as correct.
Often, this expression is also used when the measuring system is
adjusted at the same time (see adjusting).
Electrode zero point The zero point of a pH electrode is the pH value at which the
electromotive force of the pH electrode at a specified temperature is
zero. Normally, this is at 25 °C.
Electromotive force of
an electrode
The electromotive force (voltage) U of the electrode is the measurable
electromotive force of an electrode in a solution. It equals the sum of
all the galvanic voltages of the electrode. Its dependency on the pH
results in the electrode function, which is characterized by the
parameters, slope and zero point.
Junction The junction is a porous body in the housing wall of reference
electrodes or electrolyte bridges. It forms the electrical contact
between two solutions and makes electrolyte exchange more difficult.
The expression, junction, is also used for ground or junction-less
transitions.
Measured parameter The measured parameter is the physical dimension determined by
measuring, e. g. pH, conductivity or D.O. concentration.
Measured value The measured value is the special value of a measured parameter to
be determined. It is given as a combination of the numerical value and
unit (e. g. 3 m; 0.5 s; 5.2 A; 373.15 K).
Molality Molality is the quantity (in Mol) of a dissolved substance in 1000 g
solvent.
Offset potential The measurable potential of a symmetrical electrode, the membrane
of which is immersed in a solution with the pH of the nominal electrode
zero point. The asymmetry is part of the offset potential.
ORP voltage The ORP is caused by oxidizing or reducing substances dissolved in
water if these substances become effective on an electrode surface
(e. g. a gold or platinum surface).
pH value The pH is a measure of the acidic or basic effect of an aqueous
solution. It corresponds to the negative decadic logarithm of the molal
hydrogen ions activity divided by the unit of the molality. The practical
pH value is the value of a pH measurement.