Hanna Instruments HI 901 - Manual (Page 52)

5-12
METHODS
As a result, far from the end point, larger doses are made, reducing the total titration time.
Closer to the end point, smaller doses are made, providing more data and higher accuracy in
the critical end point region.
The following parameters must be set:
min Vol: Sets the smallest dose volume to be dispensed during titration.
The min Vol must be greater or equal than:
0.001 mL for a 5 mL burette
0.001 mL for a 10 mL burette
0.005 mL for a 25 mL burette
0.005 mL for a 50 mL burette
max Vol: Sets the largest dose volume to be dispensed during titration.
The max Vol must be lower or equal to 4.000 mL.
delta E: Sets the fixed potential jump that has to be achieved after each titrant dose.
The allowed range is between 0.1 and 99.9 mV.
Recommendations for dosing parameters:
For titrations with stepper titration curves the recommended settings are:
delta E = 3.5 to 9 mV
min Vol = 0.010 to 0.025 mL (for a 25 mL burette)
max Vol = 0.075 to 0.250 mL (for a 25 mL burette)
For titrations with flat titration curves the recommended settings are:
delta E = 10 to 15 mV
min Vol = 0.050 to 0.150 mL (for a 25 mL burette)
max Vol = 0.400 to 0.600 mL (for a 25 mL burette)
In order to achieve maximum accuracy and reproducibility, it is recommended that 20% to
80% of the nominal volume of the burette is consumed. If lower or higher volumes of titrant
are required, it is recommended to use the optimum burette volume as follows: 5, 10, 25 or
50mL.