Construction of a Photometer as an Instructional Tool for Electronics and Instrumentation

• Published in: Journal of chemical education Vol. 91; no. 5; pp. 747 - 750
• Main Author: McClain, Robert L
• Format: Journal Article
• Language: English
• Published: Easton American Chemical Society and Division of Chemical Education, Inc 13.05.2014; American Chemical Society
• Subjects: Chemistry; Chromium; College students; Electronic components; Electronics; Hexavalent chromium; Instrumentation; Instruments; LCDs; Liquid crystal displays; Microcontrollers; Organic chemistry; Photometers; Sampling instruments; Science education; Students; Water analysis; Water sampling; Hands-On Learning/Manipulatives; Spectroscopy; Upper-Division Undergraduate; Analytical Chemistry; Laboratory Computing/Interfacing; Laboratory Instruction; Laboratory Equipment/Apparatus; Water/Water Chemistry; Aqueous Solution Chemistry
• ISSN: 0021-9584; 1938-1328
• DOI: 10.1021/ed400784x

An introductory electronics laboratory unit for the undergraduate chemical instrumentation course is presented. In this unit, students use basic electronic components to build a functioning photometer. Students interface the photometer to a microcontroller and write an Arduino program to collect the signal, calculate the absorbance, and display the result on a liquid crystal display (LCD). Students use their home-built instruments to measure the concentration of hexavalent chromium in a series of standard solutions and determine the figures of merit: sensitivity, detection limit, and dynamic range of the instrument. They also used their instrument to measure the concentration of hexavalent chromium in an unknown water sample.