Sunday, June 21, 2009

Penentuan angka saponifikasi ( Saponification Number ) dengan alat potensiomter ( titrino/titroprocessor )

Alat yg digunakan :
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0232.100 combined pH glass electrode; input 1

Pereaksi :
Konsentresi c(HCl) = 1 mol/L; D0

Sampel :
app. 2 g minyak bunga matahari
25 mL c(KOH) = 0.5 mol/L in ethanol
app. 10-20 mL dist. water

Rangkuman
• Perhitungan:

Sapon.No=(C01-EP1)*C02/C00;1;mg/g

Sapon.No = saponification number in mg KOH per g of sample
C01 = consumption of blank sample (12.199 mL)
C02 = mg KOH / 1 mL titrating agent (56.1)

. Jawaban

Sapon.No = (12.199-5.271) x 56.1 / 2.0224 = 192.2 mg/g

EP1 = 5.271 mL
C00 = 2.0224 g

• Preparasi Sampel :
Weigh out approx. 2 g sample in a round-bottomed flask. Add 25 mL alcoholic KOH solution plus a few boiling beads and allow to boil lightly for at least 30 min. Shake from time to time. Finally rinse the content of the round-bottomed flask into a beaker with a small quantity of dist. water and back titrate the excess of potassium hydroxide with HCl. A blank control sample should be prepared and treated identically. Enter the blank value as C01.

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

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