Metrohm 794 Basic Titrino - Manual (Page 180)

6.3. User methods
794 Basic Titrino
176
6.3.12 "Perox.No"
Determinationof the peroxid number of edible
oil sand fats.
Electrode:
6.0431.100 Pt-Titrode, at measuring input 1.
Titrant:
c(Na
2
S
2
O
3
) = 0.01 mol/L, to be prepared daily
from 0.1 mol/L.
Sample:
Weigh app. 5 g sample into an Erlenmeyer
flask and dissolve in 10 mL glacial acetic
acid/1-decanol 3:2. Add 0.2 mL saturated KI
solution, shake for 5 s and store in the dark
for 1 min. Rinse solution into the titration ves-
sel with dist. water and titrate immediately.
Same treatment for blank sample.
Remarks:
The sample must be stirred very well during
the titration, in order to obtain a good emul-
sion.
Reference:
Metrohm Application Bulletin Nr. 141
– Result in milli-equivalent O
2
/kg
– Sample size in g
– Calculation factor
– Consumption of the blank sample in mL
'pa
794 Titrino 01102 794.0010
date 2002-01-03 time 09:56 0
DET U Perox.No
parameters
>titration parameters
meas.pt.density 4
min.incr. 10.0 µl
titr.rate max. ml/min
signal drift 50 mV/min
equilibr.time 26 s
start V: OFF
pause 0 s
meas.input: 1
temperature 25.0 °C
>stop conditions
stop V: abs.
stop V 99.99 ml
stop U OFF mV
stop EP 1
filling rate max. ml/min
>statistics
status: OFF
>evaluation
EPC 5
EP recognition: all
fix EP1 at U OFF mV
pK/HNP: OFF
>preselections
req.ident: OFF
req.smpl size: value
activate pulse: OFF
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'fm
794 Titrino 01102 794.0010
date 2002-01-03 time 09:56 0
DET U Perox.No
>calculations
Perox.No=C01*(EP1-C30)/C00;2;mE/kg
C00= 1.0
C01= 10
C30= 0.0
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