Advanced analytical tools for the investigation of licit and illicit drug residues in water

Abstract

The University of Queensland, Australia). It is divided into three sections and consists of six scientific articles and one review article (Scientific For my family Article 1).The first section consists of three research articles and deals with the use of high resolution mass spectrometry (HRMS) in the screening and occurrence of PIDs in environmental waters of three countries: Colombia, Italy and Spain. The use of different HRMS instruments (QTOF and LTQOrbitrap) combined with in-house and online databases of up to thousands of compounds enabled numerous compounds to be detected and identified. A continuously-updated in-house database of more than 1000 PIDs and metabolites was made incorporating their exact mass, and also adduct formation, fragment ions and retention time when a standard was available. This entire database was used for the first work, investigating influent and effluent WW as well as SW samples from Bogotá, Colombia, leading to the identification of 40 compounds across all samples (Scientific Article 2). A subset of approximately 100 of the most commonly identified compounds was used in the next work, looking at the use of two HRMS instruments (QTOF and Orbitrap) in the suspect screening of WW and SW samples from Italy and Spain, with up to 28 compounds at least detected (Scientific Article 3). Finally, a non-target screening approach was made using two advanced deconvolution software and incorporating two databases: one of 250 PIDs and the ChemSpider database, with more than 20 compounds being tentatively identified (Scientific Article 4).The second section consists of two research articles and covers the development and utilisation of two retention time prediction approaches in the identification of PIDs in waste and environmental water samples. Initially, a very simple approach was made, using only logKow and a combined in-house and Waters database of 595 reference standards. This led to a prediction accuracy of approximately 70-80% within a retention time window of ±2 minutes. A comparison was made to see whether reducing the mass extraction window incrementally from 50mDa to 5mDa would result in more peaks being removed than the prediction method.Summary ii It was found that even at the narrowest window investigated, this prediction method resulted in almost one quarter of all chromatographic peaks able to be removed as false positives (Scientific Article 5).While this simple approach showed itself quite useful, a more precise method was hoped to aid in the identification of transformation products for which no reference standards are available. Artificial neural networks were thus investigated and found to be much more precise, with up to 95% of all compounds being within a ±2 minute window, leading to the tentative identification of ten metabolites and transformation products and several other compounds for which standards were unavailable (Scientific Article 6).Finally, the third section consists of one research article on the quantitative analysis of new psychoactive substances (NPS) u...