Reference no: EM132681458

How do we determine the structures of substances?

In this course, you are introduced to several structural analysis instrumental techniques. Lab Assignments 7 and 8 will focus on one of these techniques, mass spectrometry (MS). MS is a widely used and highly powerful technique that enables chemical structural identification through ionization, fragmentation, and mass analysis of molecular species. This technique is used in a variety of research areas and industrial applications, including drug synthesis and pharmaceutical analysis, forensic analysis of trace evidence and explosives, and proteomics (e.g., protein sequencing). Mass spectrometry shines in the identification of individual substances present in complex chemical mixtures; however, mass spectrometry, in its own right, is not a separation technique. As a result, mass spectrometry is often coupled with separation techniques, such as gas chromatography. As you learned in LA 6, gas chromatography is a valuable technique for separating, identifying, and quantifying volatile compounds, but it is incapable of providing information about the chemical structures of such compounds. By using gas chromatography- mass spectrometry (GC-MS) as a hyphenated technique, one can obtain the best of both worlds, superb separation with structural identification. LAs 7 and 8 will focus on the technique of GC-MS as a powerful structural analysis tool for the separation and identification of components of unknown mixtures.

To analyze a mass spectrum:

1) Identify the molecular ion peak and base peak.

2) Identify the M + 1 and/or M + 2 peak(s).

3) Attempt to identify several of the largest abundance fragment ions.

Attachment:- Lab Assignments.rar