Which electrode for which titration?

Titrant	Specifics	Electrode description*	Order No.	Reference Electrolyte	Remarks
Aqueous acid/bases		Ecotrode Plus	6.0262.100	c(KCl) = 3 mol/L 6.2308.020
	alkaline samples	Unitrode	6.0259.100	c(KCl) = 3 mol/L 6.2308.020
	titrations performed at high temperatures	Unitrode	6.0259.100	Idrolyte 6.2308.040
	titrations with small sample volumes	Combined LL micro pH glass electrode OR Combined flat membrane pH glass electrode	6.0234.100 6.0227.100	c(KCl) = 3 mol/L 6.2308.020	Shaft diameter 6.4 mm, minimal immersion depth; 10 mm Shaft diameter 12 mm, minimal immersion depth; 1–2 mm
	titrations in water with low conductivity	Aquatrode plus	6.0257.000	c(KCl) = 3 mol/L 6.2308.020	Typical application: water analysis - p&m value etc.
Perchloric acid	See AB 80 and Monograph"Non-aqueous titration of acids and bases with potentiometric endpoint indication"	Solvotrode - combined LL pH glass electrode, ground-joint diaphragm (PCTFE)	6.0229.100	c(LiCl) = 2 mol/L in ethanol 6.2312.010	easy to clean sleeve diaphragm IMPORTANT: When not in daily use, store in LiCI sat. in ethanol and soak membrane in distilled water before use. However, when in daily use, store in distilled water, so that only the membrane is immersed, not the diaphragm. Before the measurement lift the diaphragm sleeve slightly and allow a small amount of electrolyte to flow out. Rinse the electrode with distilled water, replenish the reference electrolyte and start the titration (see bottom of chart). IMPORTANT: Never fill the Solvotrode with LiCIO4 in glacial acetic acid!
TBAOH	See AB 80 and Monograph"Non-aqueous titration of acids and bases with potentiometric endpoint indication"	Solvotrode - combined LL pH glass electrode, ground-joint diaphragm (PCTFE)	6.0229.100	c(TEABr) = 0.4 mol/L in ethylen glycol1 6.2320.000
Potassium methylate		Solvotrode - combined LL pH glass electrode, ground-joint diaphragm (PCTFE)	6.0229.100	c(TEABr) = 0.4 mol/L in ethylen glycol1 6.2320.000
Cyclohexyl-amine		Solvotrode - combined LL pH glass electrode, ground-joint diaphragm (PCTFE)	6.0229.100	c(LiCl) = 2 mol/L in ethanol 6.2312.010
Silver nitrate	AB 25	Ag-Titrode, possibly Ag2S coated	6.0430.100
arsenite, cerium sulphate, iron (III), iodine, potassium bromate, sodium nitrite, sodium thiosulphate, oxalic acid, permanganate, titanium	For titrations where the pH value during the titration doesn't change.	Pt-Titrode	6.0431.100		Electrode is also available with a plug-in head S (6.0431.500 )
	For titrations during which the pH value changes.	Combined LL Pt-ring electrode	6.0451.100	c(KCl) = 3 mol/L 6.2308.020
Karl Fisher reagent		Double Pt-wire electrode	6.0338.100
Cr3+ , Fe2+,	Also for COD titrations	Micro Au-Titrode	6.0435.110		L = 160 mm, Loger version available: (6.9904.023), L= 250 mm
EDTA	Back-titration of the BaCl2 excess. For sulphate determination see AB 140.	Polymer membrane electrode, Ca2+	6.0508.110	c(KCl) = 3 mol/L 6.2308.020	a separate reference electrode is needed. Order no: 6.0750.100
EDTA Complexon® III and IV	Determination of Al, Ba, Ca, Cd, Bi, Co, Fe, Mg, Ni, Pb, Zn. See AB 125	Ion selective electrode Cu2+	6.0502.140	c(KCl) = 3 mol/L 6.2308.020	a separate reference electrode is needed. Order no: 6.0750.100
	Determination of Ca, Mg, See AB 125	Polymer membrane electrode, Ca2+	6.0508.110
Surfactants in aqueous media	Tego® trant A 100,2 see AB 233	Ionic surfactant electrode	6.0507.120	c(KCl) = 3 mol/L 6.2308.020	a separate reference electrode is needed. Order No: 6.0726.100
	sodium lauryl sulphate, see AB 233	«Cationic surfactant» electrode	6.0507.150	c(KCl) = 3 mol/L 6.2308.020	a separate reference electrode is needed. Order No: 6.0726.100
	Sodium tetra phenyl borate, see AB 230, AB 263	NIO surfactant electrode	6.0507.010	Inner chamber of the reference electrode: c(KCI) = 3 mol/L (6.2308.020) Outer chamber: c(NaCL) = 1 mol/L	a separate reference electrode is needed. Order No: 6.0726.107
Non aqueous surfactants	Nonaqueous media, solvents as Chloroform, MIKB, see AB 269	Surfactrode resistant	6.0507.130	c(KCl) = 3 mol/L 6.2308.020	a separate reference electrode is needed. Order No: 6.0726.107 electrode not suitable for high salt concentrations and pH > 10
	Nonaqueous media, solvents as MIKB Two phase titration, see AB 269	Surfactrode refill	6.0507.140	c(KCl) = 3 mol/L 6.2308.020	a separate reference electrode is needed. Order No: 6.0726.107 electrode not suitable for Chloroform
AB = Application Bulletin * All these electodes are equipped with a Metrohm plub-in head G3 1) TEABr 0.4 mol/L tetra ethyl ammonium bromide in ethylene glycol (6.2320.000) is an electrolyte solution for non-aqueous titrations. It is very useful when titrating low acid contents with TBAOH. In such cases the LiCI sat. in ethanol (6.2312.000) would cause an alkali error during the measurement. The Solvotrode is a combined pH glass electrode specially designed for non-aqueous titrations. This electrode is normally filled with LiCI sat. in ethanol. However, when titrating with TBAOH we strongly recommend replacing the CiCI electrolyte with 0.4 mol/L TEABr in ethylene glycol. This electrolyte can of course also be used for all other non-aqueous titrations with various titrants. 2) TEGO trant A 100 6.2317.000 (6 g) 6.2317.010 (60 g) Available on request 6.2317.020 (500 g) 3 To connect an electrode with plug-in head G to a Titrino or 726/796 Titroprocessor, use one of the following cables: 6.2104.020 (1 m), 6.2104.030 (2 m) or 6.2104.040 (3 m); to connect an electrode an electrode with plug-in head S to the above instruments, use cable 6.2104.510 (1 m). See Metrosensor Electrode Catalog for additional information. Storage of the Solvotrode when not in daily use: Store the Solvotrode in LiCI sat. in ethanol. Use a normal electrode holder. More information on Electrodes > See also: which electrode for which application? > Metrosensor On-line Catalog > Metrosensor Electrodes Catalog for download (Info Center -> Products)

Titration application

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Product Categories for titration application

Titration Instruments - (54 companies)

Titration instruments are used to determine the concentration of dissolved substances. Titration is based on a complete chemical reaction between the specific substance, the analyte, and a reagent or titrant of known concentration that is added to the sample

Titration Method:

• Manual
• Autotitration

Titrant Adding Method:

• Volumetric
• Coulometric

Titration Indication Method:

• Voltametry
• Potentiometry
• Amperometry
• Photometry

Two-phase titration rendered obsolete

A Metrohm UK product story

Edited by the Laboratorytalk editorial team Oct 27, 2003

PVC membrane electrode has ionophore/plasticiser membrane composition optimised for the determination of ionic surfactants

The Metrohm High Sense Surfactant Electrode renders two-phase titration obsolete - no more need for toxic chloroform.

Surfactant analysis is extremely important the world over.

Surfactants are crucial constituents, particularly in cosmetics, detergents, cleansers and pharmaceuticals.

Whether in formulations or starting materials - the content should be determined as quickly, precisely and accurately as possible.

The hitherto usual two-phase titration employs chloroform, a solvent nowadays frowned upon.

Further, in several cases the titration endpoint can be detected only with difficulty and the titration cannot be automated.

The Metrohm High Sense Surfactant Electrode is a PVC membrane electrode whose membrane composition (ionophore/plasticiser) has been especially optimised for the determination of ionic surfactants.

The potential is formed by a specific interaction between the ion carrier incorporated in the PVC membrane and the analyte ions (surfactants) in the sample solution.

This interaction produces an electrical potential difference at the phase boundary sample solution/membrane that can be measured against a reference electrode.

The High Sense Surfactant Electrode has a working life of about one year or around 10,000 titrations, but should not come into contact with organic solvents such as acetone, tetrahydrofuran and chloroform.

The Titroprocessors or Titrinos are suitable for use as a titrator.

The choice of titrant is very important.

The lower the solubility of the compounds formed, ie, the longer the chains, the steeper and more pronounced the potential jumps.
The titrants are preferably used as 0.004mol/l solutions.
For anionic surfactants, the Tego trant A 100 titrant, available from Metrohm, has proved outstanding, whereas for cationic surfactants sodium dodecylsulphate (Merck 12533 or Fluka 71727) is normally used.
A large number of practical titrations have been performed in the Metrohm application laboratory.
These are described in Application Bulletin No 233 available free from Metrohm UK.