Penentuan angka asam dg alat potensiometer

Alat yg digunakan
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0133.100 pH glass electrode; input 1
6.0726.100 Ag/AgCl double junction reference electrode
(LiCl sat. in ethanol)

Reagents
c(NaOH) = 0.1 mol/L; D0

Sample
app. 5-10 g sunflower oil
50 mL ethanol / diethylether (1 : 1), neutralized

Remarks
• Calculations:

Acid.No=EP1*C01/C00;2;mg/g
FFA=RS1*C02/C03;2;

Acid.No = acid number in mg KOH per g of sample
FFA = free fatty acid
C01 = mg KOH / 1 mL titrating agent (5.61)
C02 = relative molecular mass (282 for oleic acid)
C03 = factor (561)

. Answer

Acid.No = 0.150 x 5.61 / 10.3223 = 0.08 mg/g
FFA = 0.08 x 282 / 561 = 0.04

RS1 = 0.08
EP1 = 0.150 mL
C00 = 10.3223 g

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