In this Determination of the Bromine Index of Petroleum Hydrocarbons Using Electrometric Titration , the repeatability RSD was less than this Method, the repeatability RSD was less than 1 %, shows that excellent accuracy can be achieved.
ASTM D 2710
In ASTM D 2710, constant voltage polarization titration is stipulated as the measurement method.
In this measurement method, a constant voltage is applied between the twin platinum electrodes, and the change in current as titration progresses is monitored.
Before the end point, the bromine is consumed through addition to the unsaturated bonds, so there is essentially no flow of current and a constant current value is shown.
When the titration reaction is complete, if there is even a slight amount of excess bromine, a current will flow in the twin platinum cathode due to bromine reduction, and a sharp increase in the current value will be observed.
The higher the bromine concentration, the longer the increase in the current value continues, so no inflection point appears in the titration curve.
In this Application Note, automatic intersection detection was used as the end point detection method.
This function automatically detects the end point at the intersection of two tangent lines drawn at the end of the titration curve.
If the end point cannot be detected automatically, there is also a function that uses the intersection of two manually drawn tangent lines as the end point.
KEM’s titrators allow users to perform measurements in accordance with ASTM D 2710.
Apparatus:
Main unit : Automatic potentiometric titrator (polarization titration preamplifier :POT)
Electrode : Twin platinum electrode, Temperature compensation electrod