Penentuan angka peroksida dg alat titrino/titroprocessor

Equipment
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0431.100 Pt Titrode; input 1

Reagents
c(Na2S2O3) = 0.01 mol/L; D0
Prepared daily from c = 0.1 mol/L

Sample
app. 5 g sunflower oil
50 mL glacial acetic acid / chloroform (3 : 2)
1 mL KI saturate
100 mL dist. water

Remarks
· Calculations:

Perox.No=(EP1-C01)*C02/C00;2;meq/kg

Perox.No = peroxide number in meq.O2/kg
C01 = consumption of blank sample (0 mL)
C02 = factor (10)

. Answer

Perox.No = 0.8874 x 10 / 5.0188 = 1.77 meq/Kg

EP1 = 0.8874 mL
C00 = 5.0188 g

· Sample preparation:

Weigh out accurately 5 g sample in an Erlenmeyer flask and add 50 mL of the glacial acetic acid / chloroform mixture. Then add 1 mL of the KI solution and shake during 5 s. Now allow the mixture to stand for about 1 min. in a dark place. After this, rinse the contents of the Erlenmeyer flask out into a beaker with 100 mL dist. water and immediately back-titrate the iodine thus liberated with sodium
thiosulphate. A blank control sample should be prepared and treated in the same way. Enter the blank value as C01. The sample must be stirred well during the titration, in order to obtain
a good emulsion.

Literature
· Metrohm Application Bulletin No. 141: Analysis of edible oils and fats.