PENENTUAN ANALISIS KALSIUM DAN MAGNESIUM DALAM PRODUK SUSU

Alat yg digunakan
Potentiometer = 751 GPD Titrino / Titroprocessor

Electrode = 6.0502.140 Cu2+ sensitive indicator electrode; input 1
6.0726.100 Ag/AgCl double junction reference electrode (KNO3 sat.)

Pereaksi
c(EGTA) = 0.1 mol/L; D0
c(Cu complex) = 0.100 mol/L; D1
Buffer solution pH = 10; D2

Sampel
app. 10 g milk

Remarks
· Calculations:

Calcium=C70*C01*C02*C03/C00;3;%

Calcium = content of calcium in %
C01 = concentration of titrating agent (0.1 mol/L)
C02 = molecular mass of calcium (40.08 g/mol)
C03 = factor for % (0.1)
C70 = EP1 from submethod Milk-Ca3

. Answer

Calcium = 3.008 x 0.1 x 40.08 x 0.1 / 10.0516 = 0.12%

C70 = 3.008

· Reagents:
c(EGTA) = 0.100 mol/L:
38.04 g EGTA - ethylene glycol-0,0’-bis-(2-aminoethyl)-N,N,N’,N’-tetraacetic acid are added to a 1 liter volumetric flask, dissolved in 250 mL c(NaOH) = 1 mol/L and the solution made up to the mark with dist. water.

Cu complex:
EGTA titrant (100 mL) is mixed with 100 mL of a solution containing 0.2 mol/L NH4Cl and exactly 0.100 mol/L Cu(II)nitrate. Titration can used to check that this solution contains no excess of Cu(II) or EGTA.

Buffer solution pH = 10:
54 g NH4Cl is dissolved in ca. 400 mL dist. water in a volumetric flask, 300 mL w(NH3) = 0.25 (25%) added and the solution made up to 1 liter with dist. water.

· The method „Milk-Ca3“ can also be used as work-alone method
(without TIP). Add the Cu complex-solution and the buffer solution
manually.

Literature
· Metrohm Application Bulletin No. 235: Potentiometric titration of Ca
(Mg) in milk products