Determination of p and m Value with Potentiometric Method

Equipment
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0239.100 combined pH glass electrode; input 2

Reagents
c(HCl) = 0.1 mol/L; D1

Sample
100 mL tap water

Remarks
· Values for the acid capacity of water.
p value = value of Phenolphthalein
m value = value of Methyl orange

· Calculations:

p value=EP1*C01;2;mmol/l
m value=EP2*C01;2;mmol/l

p value = p value in mmol/L (if 0.00 mmol/L, the water has an initial pH below 8.2)
m value = m value in mmol/L
C01= titer of titrating agent (1.0)

p value= 0.00 mmol/l
m value=5.653 x1.0 = 5.65 mmol/l

EP1 = 0.00 mL
EP2 = 5.653 mL

· The dosing unit is external D1. This method can therefore be used directly in the TIP „Hardness“ (Application 2-4), an automated water analysis method.
· Calibrate the electrode for the SET titration.
· For automatic curve output add in , >report “curve“.

Literature
· DIN 38 409, Teil 7 (19)