The materials examined by mass spectrometrists may have hundreds to thousands of unique components in a wide concentration range. The spectra are very complex; to even a trained eye, two mass spectra of related but different samples are virtually indistinguishable. So how does one decipher and tabulate thousands of chemical formulas and relative abundances without losing the important details?

As mass spectrometrists, we regularly encounter complex samples. Frequently, we're asked to isolate, identify, and quantify analytes from complex matrices like body fluids or tissue, soil, water, agricultural commodities, or process streams. When performing examinations in the presence of impurities and chromatographic or spectral interferents, we apply a variety of separation tools and protocols. Eventually, we produce an aliquot of material that is, we expect, clean enough to provide unambiguous results. Yet even then, the extreme lengths we took to produce that aliquot might have failed to deliver us from our dilemma. At such times, we resort to our most sensitive means of analysis — highly selective mass spectrometry (MS) techniques like ion mobility or multiple reaction monitoring (MRM) — to eliminate isobaric interferences.

For another group of researchers, though, the whole sample is the analyte. For them, extracting and analyzing a part of the sample is of no use, and only a compositional characterization of the entire sample provides the information required to address the experiment's goals. The materials examined by these scientists may have hundreds to thousands of unique components, in a wide concentration range. The spectra are very complex. Even to a trained eye, two mass spectra of related but different samples are virtually indistinguishable, and it is the identification and relative quantification of their components that tells the story. Nevertheless, looking at tabulations of thousands of chemical formulas and relative abundances can quickly glaze the eyes of any observer, while important details get lost in the blur of numbers.

Yet even the ability to perform such a remarkable feat is not answer enough. The development of visualization tools that condense tables of chemical formulas into easily interpretable plots and images useful to pipeline operators and refinery process engineers plays a major role in the analysts' success. With such pictures, they can readily convey the composition of a single sample and compare samples from different sources or processing conditions.

Over the course of more than 20 years of research in petroleum analysis, the NHMFL scientists have become widely recognized as world leaders in this field, with an extensive publication record covering their analysis and visualization techniques. Now, the introduction of a new generation of affordable, high-resolution, high-accuracy mass spectrometers makes possible the routine generation of high quality mass spectral data outside the confines of a national laboratory. Thus, scientists working in domains other than petroleum have investigated ways to apply these petroleum-analysis techniques to their samples, some of which can be as complex as petroleum. In this column, we will meet three such scientists, from industrial, academic, and government research groups, who work with such diverse samples as formulated products, swamp water, and atmospheric aerosols.