Titration reagents

Acidimetric/alkalimetric titration
  • Neutralization reaction: acid + base
  • Endpoint indication: pH indicator or pH-meter
  • pH indicatoris added to the titration chamber, reflecting the pH range of the equivalence point. The acid-base indicator indicates the endpoint of the titration by changing color.
  • Common titrants: 0.1 M NaOH (35263) and 0.1 M HCl (35335)
Redox titration:
  • Reduction-oxidation reaction: oxidizing agent + reducing agent
  • Endpoint indication: potentiometer or a redox indicator
  • Aredox indicator is an indicator which undergoes a definite color change at a specific potential(ferroin, methylene blue, viologen)
  • Common reagents: Potassium permanganate 0.02 mol/L (35186), Iodine 0.05 mol/L (0.1 N) (35090), Sodium thiosulfate 0.1 mol/L (35245 )
Complexometric titration
  • Formation of a complex between the analyte and the titrant
  • Useful for the determination of a mixture of different metal ions in solution
  • Common indicators: organic dyes as Eriochrome Black T, Eriochrome Red B, Patton Reeder, or Murexide.

Color change shows that the indicator has been displaced (usually by EDTA) from the metal cations in solution when the end point has been reached. Thus, the free indicator (rather than the metal complex) serves as the endpoint indicator.

  • Water hardness (Ca and Mg), determination of calcium and magnesium.

NTA = Nitrilotriacetic acid (34539)
EDTA = Ethylenediaminetetraacetic acid (03610)
EDTA-Na2 = Ethylenediaminetetraacetic acid, disodium salt (34549)
DCTA, CyDTA = trans-1,2-Diaminocyclohexane tetraacetic acid (34588)
DTPA = Diethylenetriaminetetraacetic acid (34589)
EGTA = Ethyleneglycolbis-(2-aminoethyl ether)-N,N,N’,N’-tetraacetic acid (34596)
HEDTA-Na3 = N-(2-Hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid trisodium salt (34461)

Titration reagents are available as:

  • Ready to use solutions
  • FIXANAL® concentrates  – Final concentration is user-specified
  • VOLPAC® (5L and 10 L) –  easy handling, easy to store and lab shelves, titration without contamination, adapter for titration devices

Titers of volumetric and buffer solutions are adjusted against BAM and/or NIST standard reference materials

BAM – German Federal Institute for Materials Research and Testing
– National Institute of Standards and Technology, USA