Metrohm 781 pH/Ion Meter User Manual
Page 91
6 Methods / Parameters
780/781 pH/Ion Meter, Manual
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type:
add, sub
In general – and also in this Manual – when dealing with standard and
sample addition techniques it is addition which is described. It is also
possible to carry out a standard or sample subtraction, for example by
precipitation reactions. The appropriate type is set here.
conc.std.
1.0E-30...1.0...1.0E+30
The concentration of the standard solution used is to be entered here,
regardless of whether it is to be added during standard addition or al-
ready present for sample addition.
report:
OFF, short, full, line
After the addition run you can automatically output the result in the form
of report. You can choose between the '
short
' version containing all the
relevant data and the '
full
' version, which also shows the measuring
curves as a graph (see Section 7.2.5). The '
line
' setting supplies re-
ports with the most important data in the same form as in the measur-
ing point reports for direct measurements.
The '
short
' and '
full
' reports can also be produced later under
<REPORT>.
addition:
manual, auto dos, auto
Standard or sample addition can be carried out in various ways:
manual
The standard or sample solution is added manually at defined
volume increments.
no.of additions 1, 2, 3,...19
The number of additions is entered here. If only one addition is
made then the program will adopt for the slope the existing value
from the current calibration data of the electrode used. This will
also be corrected accordingly if measuring temperature changes
in comparison to the calibration temperature. This adoption of the
existing slope also applies when a standard or sample addition
with several additions is canceled with <MODE> or <QUIT> af-
ter the first addition and then confirmed with <ENTER>.
However, please note that, as for the calibration of ion-selective
electrodes, at least two additions should be made (three to five or
even more would be better). The possibility of terminating the ad-
dition after a single standard or sample addition as described
above should only represent an absolute exception.
increment 1...n 1.0E-30...0.1...999.9 mL
The volume increment for each addition is entered here.