Autotitrator

Useful Links

Here is a link to fuller descriptions of our syringe pump and automated valve.

Here is a link to the user manual for the syringe pump and valve.

Here is a link to a page for a DIY lab robot.

The autotitrator is controlled from your computer using a microntroller and an open-source user interface. We began developing this instrument to run titration demonstrations for our university level freshman chemistry class. The titraumatic allows the instructor to run a pH titration while lecturing and to project the results for the class in real time. In contrast to a typical end-point titration, presenting the entire titration curve can be used to introduce the students to the effects of added base (or acid) outside of the end point range. That is, it can be used to teach about equilibrium, or buffers, or acid / base strengths.

While the instrument is still under development, you can see from our initial results that the instrument shows promise.

pH measurement

pH electrodes require some circuitry to give measurable voltages. The figure to the left shows a circuit for connecting a pH electrode to a microcontroller. It comes from this application note. Our original design made use of the Vernier Instruments pH probe that has the amplifiers incorporated. The down side of this strategy is that many labs will already have standard glass electrodes without the amplifier circuit. Not only does this make the electronics for the two types of electrodes incompatible, the two also have different connectors: The Vernier probes use Brittish Telecom Connectors (BTA) while the majority of electrodes use BNC connectors. To address these issues, our next prototype circuit board will have inputs for two ADC converters and we will offer expansion boards for the Vernier probe and for an amplifier / bnc connector.

Automated titrations

The video to the left demonstrates a titration curve acquired using our autotitrator in 2017.

The Titraumatic autotitrator is composed of a syringe pump, automated valve, a pH probe, electronic hardware, and software.

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