‘Do-It-Yourself’ Attenuated Total Reflectance Cell Designed and Constructed in a Laboratory Course: A Versatile and Economical Alternative to Commercial Designs

Abstract

An attenuated total internal reflectance (ATR) cell has been designed and constructed by a group of four undergraduate and graduate students during an advanced laboratory course in the School of Chemical Engineering at Purdue University. Details for the assembly, which utilizes commercially available optical components, are given in this paper. The cell employs a 45-degree trapezoidal ZnSe crystal as the ATR element. Both spherical and flat gold-coated mirrors are used to focus and align the IR beam.

The cell design presented here not only provides practical instrumentation design and implementation experience for students, it also has four major advantages imporatant for teaching purposes: a) It can be ported between different FTIR spectrometers with similar sample-compartment sizes; b) it provides an economical means for ATR spectroscopy in laboratory courses as the cost of this cell is less than half the price of similar commercial cells; c) all optical parts of the cell are easily accessible and visible for demonstration and adjustment purposes; and d) it can serve as a starting point for a variety of student experiments.