App of the Month: Infrared

In the second installment of “The Big Review,” we discuss the physical mechanism behind how molecules absorb infrared (IR) radiation. Because light can be thought of as a wave or a particle, we have two equivalent pictures of IR absorbance. We also discuss the quantum mechanics behind IR absorbance, and how this leads to the different peak types observed in IR spectrum.

This study applied principal component regression (PCR) and partial least squares (PLS) algorithms for the spectrophotometric analysis of a drug containing antazoline hydrochloride (AN) and naphazoline hydrochloride (NP) without chemical separation. Both methods showed high accuracy and precision, with results closely matching those from a reference HPLC method, and were successfully validated for analyzing commercial pharmaceutical products.

A recent study examines how Raman spectroscopy and UV-vis spectroscopy can be used in the quality control of over-the-counter medications (OTCMs), ensuring their authenticity.

This column is the continuation of our previous column that describes and explains some algorithms and data transforms beyond those most commonly used. We present and discuss algorithms that are rarely, if ever, seen or used in practice, despite that they have been proposed and described in the literature.