**About the Editor**

#### **Thomas Letzel**

PD Dr. Thomas Letzel was trained as a chemical laboratory technician, has studied chemistry in Munich and worked on his Ph.D. thesis in the field of environmental analysis at the Technical University of Munich. After a post-doctoral stay at the VU Amsterdam, he was head of the analytical research group (AFG) at the Technical University of Munich (TUM) from 2003 to 2018 and held a teaching professorship at the Ludwig-Maximilians University in Munich from 2014 to 2017. Since 2018 he is also one of the executive directors at the start-up company 'Analytisches Forschungsinstitut fur Non-Target Screening' (AFIN-TS GmbH). In AFIN-TS he continues basic and advanced research ¨ in analytical chemistry and simultaneously consults, supports and teaches common instrumental analysis, such as LC-MS, GC-MS, etc., as well as HILIC, RPLC-HILIC, SFC, and non-target screening solutions (also for commercial partners). In the past 20 years, he has devoted himself to teaching and imparting knowledge about chromatographic and mass spectrometric analysis, as well as applications in various research areas, such as environmental and food analysis, as well as pharmaceutical analysis and bioanalytics. So far, he has published 84 peer-reviewed research articles, 24 review articles, six books and more than 80 open-view articles. With www.chemnixblog.de, www.analyticsplus.org and others he actively operates educational online platforms.
