Figure 3From: Time-dependent integrity during storage of natural surface water samples for the trace analysis of pharmaceutical products, feminizing hormones and pesticidesSPE-LC-APPI-MS/MS SRM chromatograms of estrogens and progestogens obtained after 3 days of storage at 4°Cin surface water (pH = 2.8) spiked at 100 ng l-1 and 2.5% of MeOH was added.Back to article page