Metrohm 719 S Titrino - Manual (Page 140)

6.3. User methods
719 S Titrino
136
6.3.4 "p+m_Val"
Determination of the acid capacity, resp.
pK
A 8.2
and pK
A 4.3
of water and waste water.
The p-value represents the amount of acid to
be added to reach the pH value 8.2 (color
change of phenolphthalein).
The m-value represents the amount of acid to
be added to reach the pH value 4.3 (color
change of methyl orange).
Electrode:
Combined pH-glass electrode 6.0232.100 at
measuring input 1.
Titrant:
c(HCl) = 0.1 mol/L
Sample:
25 mL water
Reference:
DIN 38 409, part 7 (1979)
Remarks:
When working without carbonate addition, set
the calculation variable C02 to 0 (key
FMLA>).
C03 has to be 1 for sample size 100 mL (in-
stead of 25 mL).
This method can easily be modified to match
the particular specifications of each country,
e.g. the specified pH value may vary slightly.
– Results in mmol/L
– Concentration of titrant * 10
– Amount of carbonate addition in mmol
– Factor for 100 mL sample
– Titer c(HCl) = 0.1 mol/L
'pa
719 S Titrino 18200 719.0021
date 2002-03-13 time 12:49 0
SET pH p+m_Val
parameters
>SET1
EP at pH 8.20
dynamics 2
max.rate 5 ml/min
min.rate 5 µl/min
stop crit: drift
stop drift 20 µl/min
>SET2
EP at pH 4.30
dynamics 3
max.rate 5 ml/min
min.rate 5 µl/min
stop crit: drift
stop drift 20 µl/min
>titration parameters
titr.direction: auto
pause 1 0 s
start V: OFF
pause 2 0 s
extr.time 0 s
meas.input: 1
temperature 25.0 °C
>stop conditions
stop V: abs.
stop V 99.99 ml
filling rate max. ml/min
>statistics
status: ON
mean n= 3
res.tab: original
>preselections
conditioning: OFF
req.ident: OFF
req.smpl size: OFF
activate pulse: OFF
------------
'fm
719 S Titrino 18200 719.0021
date 2002-03-13 time 12:49 0
SET pH p+m_Val
>calculations
p value=(EP1*C36*C01-C02)*C03;2;
m value=(EP2*C36*C01-C02)*C03;2;
C01= 1.00
C02= 1.0
C03= 4
C36= 0.0
------------
'de
719 S Titrino 18200 719.0021
date 2002-03-13 time 12:49
SET pH p+m_Val
def
>formula
p value=(EP1*C36*C01-C02)*C03
RS1 text p value
RS1 decimal places 2
RS1 unit:
m value=(EP2*C36*C01-C02)*C03
RS2 text m value
RS2 decimal places 2
RS2 unit:
>common variables
>report
>mean
MN1=RS1
MN2=RS2
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