Hands-On Model of the Principle of Isotope Dilution Analysis for Use in an Interactive Teaching and Learning Classroom Exercise

Stellan Holgersson

doi:10.1021/acs.jchemed.0c01021

Abstract

A simple hands-on model for illustrating the concept of isotope dilution analysis (IDA) has been devised. The model consists of two sets of beads of different sizes, with one set representing atoms of the analyte and the other set representing solvent water molecules. Phase separation is mimicked by sieving the beads, and the results are detected according to the color of the analyte beads. In this paper, the following three IDA methods are illustrated using the model: (1) direct IDA, (2) substoichiometric IDA, and (3) IDA-assisted neutron activation analysis. The model was demonstrated for a small group of graduate students with previous knowledge of nuclear chemistry, and the response from an inquiry held after the demonstration was good. It is suggested that the model can be used in a dry chemistry laboratory exercise to demonstrate the methodological differences between the different IDA methods, without the need for costly radioisotopes or irradiation facilities. It can also be used as a tool for engaging students in meta-modeling activities.

Highlights

The concept of models in science is of fundamental importance
The model was demonstrated for a small group of seven students of mixed undergraduate and graduate (MSc chemical engineering) levels
All the students had already taken a course in general nuclear chemistry, in which isotope dilution analysis (IDA) is one of the topics

Summary

Introduction

The concept of models in science is of fundamental importance. By scientific models, the human brain has explored the world, and to have the brain understand natural science without models would probably be very difficult.Scientific models serve many purposes: often they are used for the conceptualization of an observed process, which usually increases the abstraction level. The concept of models in science is of fundamental importance. The human brain has explored the world, and to have the brain understand natural science without models would probably be very difficult. Scientific models serve many purposes: often they are used for the conceptualization of an observed process, which usually increases the abstraction level. Models can be used for the concretization or illustration of an abstract concept. The use of physically recognizable forms in scientific models is likely to help in the understanding of abstract concepts. This have been proven to be the case for pedagogical purposes and for the advancement of scientific research

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Discussion

Conclusion