Fig. 4From: Analysis of steroid hormones and their conjugated forms in water and urine by on-line solid-phase extraction coupled to liquid chromatography tandem mass spectrometryBreakthrough volume determination in HPLC water. Percentage recovery for 1, 2, 5 and 10 mL sample volume injections. 1 mL injection was considered as being 100 % (n = 3, C = 200 ng L−1)Back to article page