On-line automatic potentiometric titration

Abstract

The invention discloses an on-line automatic potentiometric titration, comprising the processes of sampling, titrating and cleaning, and is characterized in that the sampling process is as following: firstly adding a sample into a provale cup by a peristaltic pump, overflowing the sample in the provale cup through an overfall at the bottom of the provale cup; and the titrating process is as follows: a linear stepper motor is used to push a piston pump titration device to dropwise add the titration agent into the provale cup. The on-line automatic potentiometric titration of the invention ensures very high sampling accuracy, ensures repeatability of quantitative sampling within 0.2%, and is not affected by the service time; as the transmission precision of the linear stepper motor can reach 0.0005mm / mm, the highest resolution ratio can reach 0.0015mm, the resolution of the dropwise adding volume can reach 0.0003ml, the invention greatly improves the accuracy of on-line automatic titration, and can meet the requirements of high-precision on-line automatic potentiometric titration.

Description

technical field [0001] The invention relates to a potentiometric titration method, in particular to an on-line automatic potentiometric titration method. Background technique [0002] The potentiometric titration method is to insert a suitable indicating electrode and a reference electrode into the solution to be measured, measure the electrode potential value every time a certain volume of titrant is added, and plot the measured potential E against the titration volume V, and the peak value of the curve is The jump part is used to determine the end point of the titration. Potentiometric titration mainly includes sample injection, titration and cleaning processes. For the sampling process: the manual operation in the laboratory is to pipette a quantitative sample volume and add it to the measuring cup, and the automatic potentiometric titrator uses a peristaltic pump to regularly inject samples. For the titration process: manual operation in the laboratory is commonly used...

AI Technical Summary

Problems solved by technology

It can be seen that the manual operation method has defects such as low accuracy and poor repeatability; although the automatic potentiometric titration method improves the titration accuracy, the repeatability of the timing sampling of the peristaltic pump is also poor, and the longer the use time, the accuracy and The repeatability is worse. In addition, the long working time will deform the pump tube, so the accuracy and repeatability of the existing automatic potentiometric titration method still cannot meet the requirements of high-precision online automatic potentiometric titration.

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