Below is a more detailed description of our Pittcon 2021 Webinar series. You don’t have to be attending Pittcon to attend and when you sign up you are welcome to attend any and all Webinars.
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Mass Spectral Accuracy: What is it, and Why is it so Important? (March 8th, 1PM EST)
We all know how accurate mass instruments are powerful tools for the determination of the elemental composition of unknown compounds. Since every formula has a unique mass, given high enough mass accuracy we can determine the formula uniquely. In the real world, we have limited mass accuracy, and hence, the returned formula is not unique, and one must decipher the possible true formula candidate from a significant number of “matches”. However, there is another metric we can use to enhance formula ID, spectral accuracy. Spectral accuracy considers the isotope pattern of the measured ion of interest and again, is unique for each formula, so it can compliment mass accuracy to make formula ID more accurate.
In this tutorial presentation, we will show examples of the power of spectral accuracy and discuss the calibration process required to obtain high spectral accuracy. We will also demonstrate how even unit resolution MS, such as single or triple quad GC or LC systems, can use spectral accuracy to provide highly confident formula identification.
Improving and Automating GC/MS Compound ID on Quadruple MS using Accurate Mass, Spectral Accuracy, Retention Index, and Conventional Search (March 9th, 1PM EST)
GC/MS is a powerful tool for the confirmation or identification of unknown compounds. Traditionally, for single quad GC/MS compound ID relies primarily on library search results and to some degree chromatographic retention time. However, library search alone often does not provide a definitive answer and accurate mass confirmation typically requires complex and expensive high resolution instruments.
In this tutorial presentation, we will provide an overview of an automated software solution that can provide robust compound ID by combining the metrics of traditional library search, retention index determination, accurate mass determination of both the molecular ion and fragment ions, combined with a powerful deconvolution algorithm that identifies and deconvolve mixture peaks. Thanks to a novel calibration method, the system does not require the use of a high resolution instrument and provides confident fragment formula ID with typical single and triple quad instruments.
Differentiating the Loss of 43Da EI Fragments (C3H7 or CH3C=O) with Single Quad GC/MS (March 10th, 1PM EST)
EI fragment analysis from GC/MS is a powerful tool to assist in the identification of unknown compounds, particularly those not found in commercial libraries. Usually, the first step is identifying the formula for the molecular ion and then looking for common fragment losses to help piece together potential candidates for the structure. While some common fragments can be identified from integer mass losses, many times multiple fragment losses can occur for the same nominal mass. For example, C3H7 = 43.0542 Da and CH3C=O = 43.0178 Da, with only a 36.5 mDa difference. Such determinations are usually considered only possible on high resolution instruments.
In this presentation we will demonstrate that through proper calibration of single quad MS data, it is relatively straightforward to differentiate between fragments of the same nominal mass, in addition to being able to accurately determine the unknown formula for the molecular ion. This simple process can turn your benchtop GC/MS system into a powerful tool for unknown compound analysis.