Greetings Fellow Members,
The annual meeting is only a couple of months away, June 4-8, and we are pleased to post the abstracts and speakers for our upcoming workshop. As always, we will have our traditional group dinner after the workshop. Please plan to attend!
Tuesday, June 6, 5:45-7:00 pm
Environmental Analysis: Modern Sampling Techniques and Data Analysis
Environmental Applications Interest Group
Marc Engel, Imma Ferrer, Achille Cappiello, presiding
When modern sampling techniques, direct and indirect, are used to analyze complex environmental samples challenging data sets are often generated. Our workshop will focus on the analysis of complex environmental samples, and the use of data analysis tools and sampling techniques to generate the highest quality data for unequivocal identification. Three speakers will present 3-5 slides followed by discussion.
Themis: Pre-processing of Complex Mixture Data
University of Warwick, UK
Over the years, ultrahigh resolution mass spectrometry has increasingly become important for the characterization of complex mixtures. As a result, there has been a greater understanding of the complexity of petroleum-related samples and environmental samples and it is now possible to resolve tens of thousands of peaks within a complex mixture. While instrument performance was originally a limiting factor, once mass spectrometers became more capable, there was an emerging need for greater progress with data analysis methodologies. Algorithms have been developed for the assignment of molecular compositions to the thousands of peaks, but handling large amounts of data continues to present challenges. One of the difficulties faced is the reliable differentiation of reliable peaks from noise; if selecting peaks by signal-to-noise ratio alone, it is common that genuine peaks can be removed if the threshold is too high, or that noise peaks result in false positives if the threshold is set too low. We have developed a new algorithm, Themis, that processes replicate measurements, detects aberrant replicates, offers improved differentiation of peaks from noise, and then produces an averaged spectrum.
Direct Analysis of Algal Biotoxins Using Ambient Ionization and High Resolution Mass Spectrometry
Measurement Science and Standards, National Research Council Canada, Halifax, Nova Scotia, Canada
Algal biotoxins represent a threat to human and environmental health in surface and drinking water as well as seafood, and many classes of them are monitored routinely worldwide. The chemical properties, regulatory limit, and frequency of occurrence of each class determine whether sample screening using ambient ionization is possible or practical. This presentation will examine the feasibility of direct analysis of various marine and cyanobacterial toxins, with a focus on LAESI-HRMS and DART-HRMS.
Analyzing, Searching, and Archiving Data Generated by Data Dependent Analyses
MathSpec, Inc., Arlington Heights, IL
Modern high resolution LCMS instruments can produce thousands of MS/MS spectra per hour using data dependent analyses (DDA); but analyzing, searching, and archiving that vast amount of data is very challenging. A data structure of over 200000 common small molecules, designed for rapid searching against accurate-mass fragmentation data, can be used to identify many of the components. A summary of the raw mass spectral data for each component and the corresponding search results can be rapidly generated using Amazon Web Services (AWS) and be imported into a Microsoft Access database for subsequent searching, archiving, and reporting.