Ultimate 3000 isq ec

All samples were analyzed in 1000 μL of 50:50 methanol: water. Analysis was conducted on a liquid chromatography−mass spectrometry (LC−MS, Ultimate 3000/ISQ EC, Thermo Fisher Scientific) equipped with an Acclaim RSLC 120 C18 column (2.2 μm, 2.1 mm × 100 mm). Milli-Q water containing 10 mM ammonium acetate was used as the aqueous phase (A) and the organic phase (B) was acetonitrile. The flow velocity of the mobile phase was 0.3 mL min⁻¹. The injection volume was set at 25 μL and the column temperature at 30°C. The eluent gradient started with 35% (B) for 0.5 min, followed by a linear increase in phase B from 35 to 60% (0.5–10 min). The 60% phase B was held for 2 min (10–12 min) and eventually returned to the initial conditions within 1 min and held for 2 min for equilibration during the injection interval. Detection was done by a heated electrospray ionization in the negative ion mode (V = −4.5 kV). The nebulizing gas temperature was set at 450°C. A list of MS parameters of the target analytes is included in Table S2.
Whole method LODs ranged from 0.05 to 0.95 ng g⁻¹ dw (Table S3). Spike recoveries and method precision for solid sample analysis were within the range from 75% ± 4%–141% + 1% (Table S3).