Introducing NMR to Biomedical Laboratory Scientists through a Laboratory Exercise; Synthesis, Structure Determination and Quantization of Aspirin by Employing an 1 H-NMR Bench Top Instrument

Abstract

In this chemical education research study, NMR was introduced to a group of 3 students with minor chemistry background. A bench top NMR instrument was used to acquire the 1H-NMR spectra. The 1H-NMR spectra were used to monitor the synthesis of ASA and product purity. The spectrum of the product confirmed its formation, and the spectra of crude and final product allowed the students to observe the elimination of impurities upon recrystallization of the product. Further, the spectrum of the final product was used to quantify the yield through integration of the proton resonances. The use of integrals of the proton resonances for calculation of the yield of ASA is to our knowledge not described elsewhere in undergraduate experiments. A procedure for the synthesis, recording and processing of 1H-NMR spectra, as well as calculation of the yield is reported. This procedure can be implemented by undergraduate or by high school students and might as well be useful for instructors who wants to introduce NMR spectroscopy early in the curriculum of Chemistry. By including an exercise like this, the students get hands on experience to employ advanced technology that might be commonly used in the future, also in Hospital laboratories. Furthermore, it is useful to introduce one of the most demanding and advanced methods in chemistry as early as possible in the curriculum in Chemistry to promote the chemistry career.