Fig. 4From: Determination of Sudan red contaminants at trace level from water samples by magnetic solid-phase extraction using Fe@NiAl-layered double hydroxide coupled with HPLCTypical chromatograms of Ming Tombs Reservoir water samples. (a) blank; (b) spiked at 5 μg L−1; (c) spiked at 10 μg L−1Back to article page