Analysis of a Suspected Drug Sample

Abstract

This general chemistry laboratory uses differences in solubility to separate a mixture of caffeine and aspirin while introducing the instrumental analysis methods of GCMS and FTIR. The drug mixture is separated by partitioning aspirin and caffeine between dichloromethane and aqueous base. TLC and reference standards are used to identify aspirin precipitated by acidifying the aqueous layer and the caffeine is recovered by evaporating the dichloromethane. FTIR analysis of the isolates is intended to provide an introduction to both the basic operation of a FTIR spectrometer and experience in matching library reference spectra to FTIR spectra of unknowns. GCMS analysis parallels the wet chemistry separation and FTIR identification of the components in the drug mixture. Used as a re-introduction to GCMS, emphasis is placed on how GCMS combines sample separation and component analysis into one operation. This laboratory is intended to be part of a suite of vertically integrated laboratory exercises linked by a forensic theme. Proceeding experiments in the suite are centered on the theory and application of TLC for forensic analysis. Subsequent experiments are focused on the use and interpretation of FTIR and GCMS for analysis.

A Forensic Experiment: The Case of the Crime at the Cinema

“…This has had an impact on students of different levels, particularly on undergraduate students, by triggering teachers to take advantage of the topic and create new teaching tools to use as a hook to capture student’s attention. In this way, an increase in the number of new graduation and postgraduation forensic courses has been observed, as evidenced by several articles published in this Journal . − …”

Introducing ATR-FTIR Spectroscopy through Analysis of Acetaminophen Drugs: Practical Lessons for Interdisciplinary and Progressive Learning for Undergraduate Students

“…The analysis of pharmaceutical drugs to teach and train students in using IR spectroscopy is not novel, and several examples can be found in the literature. − However, most of them are exclusively focused on the practical training of the ATR-FTIR technique and/or the vibrational chemical interpretation of the IR spectra . However, the curricula of some chemistry or pharmacy university degrees may not include any training on the comparison of spectral libraries or the spectral matching using, for instance, the Pearson coefficient.…”

An Environmental Forensic Chemistry Experiment Involving Abandoned Mine Drainage Remediation

“…Most experiments prepared for undergraduate forensic chemistry laboratories involve techniques to analyze trace evidence: qualitative wet chemical testing, paper or thin layer chromatography, staining for microscopy, and separation/identification of analytes using laboratory instruments (UV–vis, FTIR, HPLC, GC, and GC–MS). Many experiments and case studies using these methods have been published in this Journal − and elsewhere. − However, the practice of additional chemical techniques educates the students about the broader spectrum of analytical work performed by forensic chemists.…”