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The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 19 (2014) pp 096-101

An Automated Titrator Based on a Microcontroller: an Interfacing Exercise for Advanced Analytical Chemistry Students

Gary A. Mabbott

Department of Chemistry, University of St. Thomas, 2115 Summit Avenue, St. Paul, Minnesota 55105, gamabbott@stthomas.edu
Received September 11, 2013. Accepted January 16, 2014.

Published: 21 March 2014

Abstract. A high precision, automated titration system was built around an analytical balance, an Arduino microcontroller board and other common lab apparatus. Interfacing the system components serves as an excellent exercise in laboratory automation for advanced undergraduate and graduate students. A computer controls the system through a scripting program (AppleScript). A terminal software application (CoolTerm) assists the computer script in communicating with the balance via a USB port in order to monitor the amount of titrant delivered. Upon prompting from the computer the microcontroller delivers titrant by turning on a pump, reads the new pH in the reaction beaker, calculates the appropriate amount to add in the next cycle and reports the new pH value to the computer. The computer sends the new data to a spreadsheet program that plots the data in real time.

Key Words: Laboratories and Demonstrations; analytical chemistry; lab automation; computer interfacing; case study; microcontroller; autotitrator

(*) Corresponding author. (E-mail: gamabbott@stthomas.edu )

Article in PDF format (622 KB) HTML format

Supporting Materials:

Constructions details for the titrant reservoir; microcontroller, MOSFET and amplifier circuits; an AppleScript program, an Excel template and an Arduino sketch for performing automated titrations are given in the supporting materials. A student handout for using an autotitrator in a quantitative analysis class is also included (615 KB).



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