To optimize RT windows, MS 1 level data was acquired for the mixture of analytical standards at the highest concentration level. From this data, we retrieved the peak width for each compound, and opted for a RT window that would be defined by ± 0.75 * peak width. For example, methylparaben (RT = 5.55 min) was detected with a baseline peak width of ~6.6 s, and, therefore, RT window was set at ±5 s. Manual fine-adjustment was also performed after, especially for compounds which are prone to suffer from relatively larger RT shifts (such as phthalates and glucuronide conjugates). Final RT windows are described for each compound in Table . Figure presents the final and optimized methods with extracted ion chromatograms, RT and RT windows for each compound of the target panel.