Monitoring acid-base, precipitation, complexation and redox titrations by a capacitively coupled contactless conductivity detector

A developed capacitively coupled contactless conductivity detector is used to monitor the process of chemical reaction in real time. Plus delivering titrant with a peristaltic pump, simple and automatic micro-titrations are realized, by using disposable glass reaction cells. All the four routine kinds of titrations, i.e. acid-base, precipitation, complexation and redox, can be performed easily, free of the exchange of working electrode. [Display omitted] •A capacitively coupled contactless conductivity detector was used to monitor micro-titration.•It resolved problems faced by contact electrochemical methods.•Portable instruments are promising to be constructed for versatile titrations.•Simple operation is a distinct advantage. Herein, an approach for versatile titration by monitoring the chemical reaction process with a developed capacitively coupled contactless conductivity detector (C4D) was developed. A disposable glass reaction cell, in which sub-milliliter titrand was loaded, was inserted into the working head stage of the C4D. Upon addition of titrant, the ionic strength and/or mobility of components in the solution changed, causing consequently change of conductivity. The C4D monitored the change in real time. A V-shaped titration curve was gained, allowing an easy identification of the endpoint. Between the elapsed time and the initial concentration of titrand, linear relationships were found for classical acid-base, precipitation, complexation and redox reaction over certain ranges, enabling the establishment of quantitative determinations. The new approach had a few charming advantages (e.g. simplicity and cost effectiveness) over contact electrochemical methods because that the solution was isolated from the working electrodes. Therefore, a development of versatile and multifunctional platform for micro-titrations is promising.