J.P. SELECTA MP-2006 Manual De Instrucciones página 87

Press 'ENTER' key, meter returns to direct reading concentration measuring mode.
During Calibration, you could press 'END' key any time to quit the calibration and return to direct
reading concentration measuring mode.
1. During blank calibration, all blank solution should be similar with the blank solution in
chemical analyze.
2. There is blank calibration in direct reading concentration mode and known addition mode.
Detailed operation is the same as this measuring mode.
4.6.3.1.2 Clear Blank Concentration
If you want to clear previous blank concentration value, you can press 'BLANK' key under direct
reading concentration measuring mode and select 'Cali Blank Conc?Clear Blank Conc' then press
'ENTER' to make blank concentration value to zero.
4.6.3.2 Known Addition Mode
Known addition is also called standard addition. Firstly, measure balance potential value of
system and then add standard solution with known concentration in measured system. Measure
balance potential value of system again, and then calculates the concentration value of measured
sample according to the changing value before and after adding. The formula is as follows:


Cs

Cx

  
( 2
1 ( ) 10
E
In which: Ｃx～ concentration value of measured sample
Ｃs～ concentration value of standard solution (added solution)
Ｓ～ electrode slope
Ｃb～blank standard concentration value
Ｅ1～Measured potential value before adding standard solution.
Ｅ2～Measured potential value after adding standard solution.
ρ ～ standard solution adding volume(Vs)/measured sample volume (Vx)
Ｅb1～Measured potential value before adding standard solution in blank calibration
Ｅb2～Measured potential value after adding standard solution in blank calibration
Before measuring, input standard solution's concentration value and adding volume, then input
sample's volume. Later measure electrode potential value E1 before adding and then measure
electrode potential value E2 after adding, meter can calculate sample's concentration value Cx
according to above formula. If you want to make blank calibration, you can separately measure
blank standard solution's electrode potential changing value before and after adding standard
solution according to the similar method, i.e. Eb1, Eb2 and then calculate the blank concentration
value of blank standard solution.
Similarly, you can select relevant ion mode according to ion electrode used (for example, if you
want to measure Na ion concentration, you can select ion mode as Na ion, please refer to
chapter 'Setup Ion Mode' for details). Set measuring parameter as ion concentration and select
'Known Addition' mode (please refer to chapter 'Setup Measuring Mode), When selection
finishes, press 'MEAS' key to start the measuring. Or you can press 'ENTER' to return to start



  
1 / )
1 1 ( ) 10
E S

Cb
 
( 2 1 / )
1
Eb Eb S
84