Treball Final de Grau en Química. Codi: QU0943. Curs acadèmic: 2019/2020 High resolution mass spectrometry (HRMS) has revolutionized the field of analytical chemistry in the last decades. Its potential allows facing up almost any analytical challenge in the food, environmental and biological fields. Briefly, the main characteristics, in comparison with the widely used MS/MS techniques are described [1]. First, the exact molecular weight is universal and easily calculated. Methods based on HRMS do not depend on the a priori availability of reference standards, whereas in MS/MS, specific transitions of compounds must be defined experimentally. Furthermore, in HRMS, a broad spectrum can be measured throughout the chromatogram, allowing determination of a virtually unlimited number of analytes. In contrast, in MS/MS, specific transitions are measured only in a time window around the determined retention time of the analytes. Second, the high resolving power in HRMS enables accurate mass measurement with high confidence in the ppm level (in terms of mass error), making it easy to identify accurate massbased analytes. As a result, HRMS has been praised for its added value for confirmatory purposes. According to the European Commission decision 2002/657/EC, with a resolving power of at least 20,000 FWHM, precursor ion (HRMS) and fragment ions (MS / HRMS) need 2 and 2.5 identification points (IPs), respectively. This contrasts with 1 and 1.5 IPs for low resolution (MS) precursors and fragment ions (MS/MS), respectively. In this way, one precursor ion and only one fragment ion are sufficient (= 4.5 IPs) in HRMS to achieve at least 4 IPs for unambiguous confirmation, while one precursor plus two fragment ions (= 4 IPs) are required in MS low resolution. Thus, the accurate mass measurement combined with the ability to generate ions from products facilitates the detection and identification of unknown compounds [1]. Third, post-run analysis of acquired spectra is possible without having to establish even additional instrumental careers. This can lead to the development of methods that can monitor a wide range of metabolites, doing possible the achievement of universal screening [1], [2]. HRMS allows selectivity for monitoring compounds that share the same nominal mass but differ in their elemental composition and therefore have a different exact mass. With these instruments the complete scan data can be simultaneously analysed, instead of the preselected ion, collect the transitions corresponding to specific compounds. In summary, HRMS can be assessed by the following properties: [2][3] [...]