Measuring mode
On upper side of the screen is the adding volume which is the sample's volume going to be added.
Volume before adding is the volume of standard solution. 'STD Conc' means the concentration
value of standard solution. The relevant concentration unit is listed on right side. The displayed
concentration of standard solution is
is 'ENTER', 'CANCEL', and 'STD' key.
This mode needn't measure the blank concentration value of blank standard solution. For detailed
operation, please refer to 'Known Adding Measuring Mode'.
4.6.4 GRAN Method
Apart from normal measuring method, you can also use GRAN method to measure the sample
with low content. According to mathematical principle of GRAN, you can get sample's
concentration with following formula:
(
)
Vs
Vx
When measure, input standard solution' concentration (Cs), Volume (Vs) and measured sample's
volume (Vx), then measure sample's electrode potential value when first standard solution is
added. Repeat the measuring for three to eight times in sequence, meter can calculate the
concentration value of measured solution.
You can select relevant ion mode according to ion electrode used (for example, if you want to
measure Ag ion concentration, you can select ion mode is Ag ion, please refer to chapter 'Setup
Ion Mode' for details). Set measuring parameter as ion concentration and select GRAN method
(please refer to chapter 'Setup Measuring Mode), When selection finishes, press 'MEAS' to start
the measuring. Or you can press 'ENTER' to return to start mode. Under start mode, press
'MEAS' key, you can also make concentration measuring
Similarly, GRAN method is the same as 'Known Addition Mode' which needs to set parameter
such as addition volume, volume before adding and standard solution concentration, etc... (Please
refer to chapter parameter setting of 'Known Addition Mode'). When setting finishes, you can
start measuring. The displayed is as follows:
100mmol/L,
/
/ 0
10
10
(
E
S
E
S
CxVx
At the bottom is 'previous STD'. On right side
/ 0
)
10
(
)
E
S
CsVs
Display chart for GRAN method
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