Margo van der Kooi is an HLO analyst. In recent years, she has focused mainly on LC-MS and GC-MS analyses of mostly water. She analyses drugs, medication, pesticides and other hazardous substances in drinking water, groundwater, surface water and wastewater. Her expertise also includes wide screening with both LC-MS and GC-MS, as well as method development and improvement. Margo developed her expertise on drug analysis by analysing wastewater from various Dutch cities. She regularly does all other analyses for water pipeline laboratories. In the past years, her activities also included wide screening with LC-MS and GC-MS of materials such as struvite.