Metrohm 719 S Titrino - Manual (Page 22)

2.4. Tutorial
719 S Titrino
18
2.4.5 Statistics, acid capacity of drinking water
Let us now determine the acid capacity of drinking water. For this, the SET (set endpoint
titration) mode is used to titrate to pH = 4.3.
Load the method "Acid", the one that you just have stored in the method memory, see
page 16 .
Set the end point pH = 4.3 and dynamics 3 as you did with your first example (key
<PARAM>). If you still feel unfamiliar with that, see page 11 again.
Now alter the calculation formula before the titration (keys <DEF>,<ENTER> and <1>).
Delete the existing formula with <CLEAR> and enter the following formula:
RS1=EP1*C01*C02
with an accuracy of RS1 decimal places 2
the unit RS1 unit: mmol/L
and the calculation constants
C01 1 (concentration of titrant ×10)
(key <C-FMLA>) C02 4 (factor for the sample size 100 mL/25 mL)
If you have a printer connected to your Titrino, you can print out the titration parameters
with the keys
<PRINT><PARAM><ENTER>.
Mount an Exchange Unit with c(HCl) = 0.1 mol/L as titrant. Add 25 mL drinking water as
sample and start the titration with <START>. During the titration the first line of the dis-
play shows the measured value and dispensed volume. The "c" in pHc shows that the
electrode assembly has been calibrated. The second line shows a "control bar", which
indicates the control deviation of the current measured value from the set end point.
If the titration runs too slow or too fast, you can change the control parameters during the
titration. If you wish to titrate faster, change the following parameters:
• dynamics: lower value, the control range becomes smaller (Attention: possibility of
titrating over the set EP)
• max.rate: bigger value
• min.rate: bigger value
You will find further details of the control parameters on page 31.
After the titration, end point volume and pH value at the end point are displayed.
pHc 6.34 0.426 ml
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