5 statistics, acid capacity of drinking water – Metrohm 719 S Titrino User Manual

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2.4. Tutorial

719 S Titrino

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

). If you still feel unfamiliar with that, see page 11 again.

Now alter the calculation formula before the titration (keys , and <1>).

Delete the existing formula with and enter the following formula:

RS1=EP1*C01*C02

with an accuracy of

RS1 decimal places

the unit

RS1 unit:

mmol/L

and the calculation constants

C01

1 (concentration of titrant ×10)

(key )

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

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 . 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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