Fig. A1. Single Reaction Monitoring (SRM) chromatograms for dopamine in the four samples analysed; transitions monitored were: 154.1 > 137.0, 154.1 > 90.9, 154.1 > 119.0 and 154.1 > 65.0 m/z. Sampling dates were 1 April 2020 (denoted by 1.4) and 6 April 2020 (denoted by 6.4