Penentuan secara Potentiometric Angka Epoxy

Peralatan
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0430.100 Ag Titrode; input 1

Pereaksi
c(HClO4) = 0.1 mol/L; D0

Sample
app. 0.2 g UHU resin
25 mL c(TBA) = 0.2 mol/L in acetic acid
TBA = Tetrabutyl ammonium bromide

Remarks
Determination reaction:
O OH
R-CH-CH-R’ + H+ → [R-CH-CH-R’]+
OH OH
[R-CH-CH-R’]+ + Br - → R-CH-CH-R’
Br
Calculations:

Epoxy.No=EP1*C01*C02*C03/C00;3;

Epoxy.No = epoxy number, number of epoxide groups per 100 g of sample
C01 = factor for conversion mL L (0.001)
C02 = concentration of titrating agent (0.1 mol/L)
C03 = factor for 100 g of sample (1000)
Stir sample in solvent during 3 minutes before titration


Answer

Epoxy.No = 8.828 x 0.001 x 0.1 x 1000 / 0.2261 = 0.390

EP1 = 8.828 mL
C00 = 0.2261 g

Literature
I. Gyenes, “Titrationen in nichtwässrigen Medien“
Ferdinand Enke Verlag, Stuttgart (1970), p. 598

Penentuan secara Potentiometric of Pure Silver Content

Peralatan
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0404.100 combined massive Ag electrode with AgBr coating; input 1

Pereaksi
c(KBr) = 0.1 mol/L; D0

Sample
app. 250 mg Ag
10 mL HNO3 65 %
100 mL dist. water

Remarks
Calculations:

Silver=EP1*C01*C02*C03*C04/C00;3;%

Silver = content of silver in % ( purity )
C01 = concentration of titrating agent (0.1 mol/L)
C02 = titer (1.0)
C03 = molecular mass of Ag (107.87 g/mol)
C04 = factor for % (100)

Answer

Silver = 22.332 x 0.1 x 1.0 x 107.87 x 100 / 257.7 =93.479 %

EP1 = 22.332 mL
C00 = 257.7 mg

Sample preparation:
Heat silver in HNO3. Allow nitrous fumes to evaporate.

AgBr coating of electrode:
Clean Ag electrode with scouring agent and electrolyse in (HBr) = 0.1 (10%) during 2 h with 5 mA using a 6.0305.000 Pt lectrode as cathode. Stir during electrolysis.

Literature
Metrohm Application Bulletin No. 61: Potentiometric determination of silver.

Penentuan secara Potentiometric dari Perborates didalam Detergents

Equipment
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0420.100 LL combined Pt electrode; input 1

Reagents
c(KMnO4) = 0.02 mol/L; D0

Sample
5 mL sample solution
20 mL w(H2SO4) = 0.30 (30%)

Remarks
Determination reaction:

5 NaBO₂*H₂O₂ + 2 MnO₄^- + 6 H⁺ → 2 Mn²⁺ + 5 O₂ + 8 H₂O + 5NaBO₂

Calculations:

Perborat=EP1*C01*C02*C03*C04*C05/C00;2;%

Perborat = fraction of perborates in %
C01 = concentration of titrating agent (0.02 mol/L)
C02 = factor for “normality“ (5/2=2.5)
C03 = molecular mass of NaBO2*H2O2*3H2O (153.86 g/mol)
C04 = conversion mL L * factor for % (0.001*100 = 0.1)
C05 = factor for dilution (20)

Answer

Perborat = 1.289 x 0.02 x 2.5 x 153.86 x 0.1 x 20 / 2.5023 = 7.93 %

EP1 = 1.289 mL
C00 = 2.5023 g

Sample preparation:
Weigh 2.5 g in a measuring flask of 100 mL. Dissolve sample with c(H2SO4) = 1 mol/L and wait for the reaction of the carbonate. When gas evolution has stopped, fill measuring flask to the mark. Pipette 5 mL of solution, add 20 mL of w(H2SO4) = 0.30 (30%) and titrate. The 6.0431.100 Pt Titrode may be used instead of the 6.0420.100 LL Pt electrode.

Literature
G. Jander, K.F.Jahr, “Massanalyse“, Sammlung Gröschen de Gruyter, Berlin, New York (1973), p. 67

Penentuan secara potensiometrik Anionic Surfactants in Shampoo, Titrino / Titroprocessor

Peralatan
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0507.120 Ionic surfactant electrode; input 1
6.0733.100 Ag/AgCl reference electrode (c(KCl) = 3 mol/L)

Peralatan
c(TEGOtrant A100) = 0.004 mol/L; D0
1,3-didecyl-2-methyl-imidazolium chloride (DDMICl)
Metrohm 6.2317.000

Sample
app. 0.2 g sample (shampoo)
5 mL Methanol puriss p.a.
10 mL Buffer solution pH = 3.0, citrate/HCl, e.g. Merck Tirisol No. 9883
60 mL dist. water

Remarks
Calculations:

Anionic=EP1*C01/C00;4;meq/g

Anionic = concentration of anionic Tensides in meq/g
C01 = concentration of titrating agent (0.004 mol/L)

Answer

Anionic = 12.638 x 0.004 / 0.2128 = 0.2376 meq / g

EP1 = 12.638 mL
C00 = 0.2128 g

Electrode preparation, maintenance and storage:
Store the Ionic Surfactant electrode dry. They are conditioned by two to three titrations. Rinse the electrode after several titrations with methanol or wipe it with a cloth moistend woth methanol and rinse with dist. water. If you use the electrode frequently, it may also be stored in a solution of 1% polyethyleneglycol 1000. In this case, the electrode is always ready to use.

Sample preparation:
Adjust the sample size in order to have a titrating agent consumption of at least 10 mL. The pH of buffer solution, the amount of added methanol may change according to the type of surfactant. See also Application Bulletin No. 233.

Literature
Metrohm Application Bulletin No. 233: Titrimetric / potentiometric determination of anionic and cationic detergents with the high-sense surfactant electrode.

Penentuan secara potensiometrik Cationic Surfactants in Fabric Softener, Titrino / Titroprocessor

Peralatan
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0507.120 Ionic surfactant electrode; input 1
6.0733.100 Ag/AgCl reference electrode (c(KCl) = 3 mol/L)

Pereaksi
c(DOS) = 0.01 mol/L; D0
Dioctylsodium sulfosuccinat M(DOS) = 444.57 g/mol, Fluka No. 86139

Sample
app. 1 g sample (fabric softener)
5 mL Methanol puriss p.a.
5 mL Buffer solution pH = 3, citrate/HCl, e.g. Merck Titrisol No. 9883
1 mL c(HCl) = 2 mol/L
60 mL dist. water

Remarks
Calculations:

Cationic=EP1*C01/C00;4;meq/g

Cationic = concentration of cationic surfactants in meq/g
C01 = concentration of titrating agent (0.01 mol/L)

Answer

Cationic = 12.631 x 0.01 / 1.0631 = 0.1188 meq/g

EP1 = 12.631 mL
C00 = 1.0631 g

Electrode preparation, maintenance and storage:
Store the Ionic Surfactant electrode dry. They are conditioned by two to three titrations. Rinse the electrode after several titrations with methanol or wipe it with a cloth moistend woth methanol and rinse with dist. water. If you use the electrode frequently, it may also be stored in a solution of 1% polyethyleneglycol 1000. In this case, the electrode is always ready to use.

Sample preparation:
Adjust the sample size in order to have a titrating agent consumption of at least 10 mL.
The pH of buffer solution, the amount of added methanol or the titrating agent may change according to the type of surfactant. See also Application Bulletin No. 233.

Literature
Metrohm Application Bulletin No. 233: Titrimetric / potentiometric determination of anionic and cationic detergents with the high-sense
surfactant electrode.

Penentuan Non-ionic Surfactants dengan NIO Electrode, Titrino / Titroprocessor

Peralatan
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0507.010 NIO surfactant electrode; input 1
6.0726.100 Ag/AgCl double junction reference electrode
(inner electrolyte c(KCl) = 3 mol/L, outer electrolyte
c(NaCl) = 1 mol/L)

Pereaksi
c(STPB) = 0.01 mol/L; D0
STPB = sodium tetraphenylborate

Sample
5 mL sample solution
3 mL c(BaCl2) = 0.1 mol/L
60 mL dist. water

Remarks
Titrating agent:

Dissolve 3.4223 g sodium tetraphenylborate in 300 mL dist. water. Dissolve separately 10 g polyvinyl alcohol in 300 mL dist. water and heat it slightly. Allow to cool and rinse both solutions in a 1000 mL flask. Add 10 mL buffer pH = 10 and fill up to 1 liter.

BaCl2 solution:
Dissolve 21 g BaCl2 or 25 g BaCl2*2H2O in dist. water, add 1 mL
conc. HCl and fill up to 1 liter.

Buffer pH = 10:
Dissolve 1.24 g H3BO4 in dist. water, add 10 mL c(NaOH) = 1 mol/L and fill up to 100 mL.

Sample preparation:

Dissolve app. 0.5 ... 1 g detergent (Renex 650 ICI; polyoxyethylene-(30)-nonylphenol, molecular mass 1541 g/mol) in 100 mL dist. water.

Calculations:

Nonionic=EP1*C01*C02/C00;4;meq/g

Nonionic = concentration of nonionic Tensides in meq/g
C01 = concentration of titrating agent (0.01 mol/L)
C02 = dilution factor for the sample solution, aliquot (20)

Nonionic = 8.795 x 0.01 x 20 / 0.5145 = 3.4189 meq/g

EP1 = 8.795 mL
C00 = 0.5145 g

Literature
Metrohm Application Bulletin No. 230: Titrimetric/potentiometric determination of non-ionic tensides (oxyethylates) with the NIO electrode