Water sources are coming under increasing pressure from agricultural runoff, algae blooms, hydrocarbon contamination and waste water discharges. Further, several thousand chemicals are released into the environment every day by these sources. Identifying each one is not practical and uneconomical; hence prioritization must be given to identify the most relevant ones. To address these issues chemometric approaches using high-resolution mass spectrometry (HRMS) are becoming increasingly common. Pattern recognition, identification of significant compounds and structural annotation of unknowns becomes critical where water matrices are becoming increasingly complex and target compounds are hard to predict. As such strategies for quality control of chemometric experiments including proper instrument settings, experimental controls, statistical pretreatment and filtering a critical to success of any chemometric experiment. Further, validation of chemometric experiments is critical for confidence in the data, minimizing the possibility of an experiment ending failure and avoiding false discovery. With these concepts in mind, appropriate use of pooled controls, sample prep blanks, replication and statistical power will be discussed. Common chemometric techniques will also be shown with water data addressing some of the challenges of these techniques and the interpretation of their results. Univariate approaches to statistical analysis using multiple hypothesis testing corrections will show how to reduce the possibility of false discovery in water data, while retaining the most relevant compounds. Additionally, principal component analysis and hierarchical cluster analysis will also be shown to show chemical relationships between water samples taken at different locations.  Finally, correlation techniques are used to find relationships between non-MS water quality measures and compounds detected in the MS analysis.  With the increasing use of HRMS in Environmental applications for identification of new and relevant contaminants, the appropriate understanding and critical requirement of appropriate QA/QC is essential in the field and will be discussed in this presentation.<br/>

Quality control, validation and strategies for statistical analysis in chemometric approaches using high-resolution MS in environmental and waste waters

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.