basics of titration
DESCRIPTION
Basics of Titration. by Michael Margreth. One of the oldest analytical methods Based on chemical reaction Determination of the volume of a standard solution (titrant) Standard solution contains a defined number of molecules Measuring volume = counting molecules TITRATION MEANS COUNTING!. - PowerPoint PPT PresentationTRANSCRIPT
Basics of Titration
by Michael Margreth
Basics• One of the oldest analytical methods• Based on chemical reaction• Determination of the volume of a standard solution
(titrant)• Standard solution contains a defined number of
molecules• Measuring volume = counting molecules• TITRATION MEANS COUNTING!
Titration
Titrant Sample
Start
Titration
Titrant Titrant + Sample
Endpoint
Titration
Titrant Titrant + Sample
End
- optical detection
- manual control
- manual addition
Titrant
Color indicator
Principle of a Manual Titration
All in one!
• Dosing
• Measuring
• Controlling
• Evaluation
Titrations Modes
• Set Endpoint TitrationSET
• Monotonic Equivalence point TitrationMET
• Dynamic Equivalence point TitrationDET
• Karl Fischer TitrationKFT
Set Endpoint Titration
volume
endp
oint
Signal[pH/mV]
Monotonic Equivalence Point Titration
equivalence point
Signal[pH/mV]
volume
equivalence point
Dynamic Equivalence Point TitrationSignal
[pH/mV]
volume
400.00
800.00
0.00 3.00
400.00
800.00
0.00 3.00
Volume increment• In MET mode the steps are always the same• In DET mode the steps are calculated by the Titrando
MET Mode
pH
V [mL]
EP1
pH
V [mL]
EP1
DET Mode
Karl Fischer Titration
volume
Endpoint
Signal[g/min]
Which mode for which titration?
SET MET DET KFT
defined endpoint
slow reaction quick reaction Karl Fischer Titration
non-aqueous titration
duration has priority
non S-shaped curve
universal method (90%)
Endpoint evaluation
tangent method circle method derivative method
Titration steps• sample preparation (homogeneity)• right electrode choice• possibly electrode conditioning• titrant preparation• titer determination• buret/ sample size choice• correct arrangement in titration vessel• stirrer rate • method parameters• results calculation• report
stirrer
buretelectrode
Arrangement
Titer• What is a titer?
Correction factor
• Why do we need the titer?To know the exact concentration of the titrant
• What is the unit?none
• When do I have to determine a titer?frequently
• How is the titer determined?With titrimetric standards
Advantages• Absolute method• Easy to carry out• Carried out very rapidly• Versatile method• Highly reproducible and correct results• Can be automated• economical
Hardware definition
System
Titrant definition
Sensor definition
Method definition
Parameters
Titration method
Titration parameters
Sensor
Dosing device
Stirrer
Direct parameters
Direct parameters
Start conditions
Titration parameters
User defined parameters
Measurement density
EP1
6,0
6,5
7,0
7,5
8,0
8,5
0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 5,5 6,0
DET Mode
pH
V [ml]
EP1
6,0
6,5
7,0
7,5
8,0
8,5
-0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 5,5 6,0
DET Mode
pH
V [ml]
• 4 default• 0 high density
• 9 low density
Stop conditions
Evaluation
Calculation
Report
Result report
Curve report