Penentuan Formaldehyde Number di dalam jus buah dg alat potensiometer

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

Pereaksi
c(NaOH) = 0.1 mol/L; D0
w(HCHO) = 0.35 (35%), adjusted to pH = 8.5 with NaOH; D1

Sampel
25 mL sample (orange juice)

Electrodes
6.0232.100 combined pH glass electrode; input 1

Remarks
• Determination reaction:
OH
H2C=O + H2N-R Þ H2C + H+
NHR
Amino groups of amino acid react according to the above reaction.

• Calculations:

Formol No = C70*C01;1;

Formol No = formol number as mL NaOH 0.1 mol/L for 100 mLsample solution
C01 = factor for 100 mL sample solution (4)
• Calibrate the electrode for the SET titration.

. Answer

Formol No = 5.634 x 4 = 22.5

C70 = 5.634

Literature
• Metrohm Application Bulletin No. 180: Automatic determination of the
formol number in fruit and vegetable juices