Fig. 4

Sample HPLC chromatograms of sea water sample taken from station 3 (Chabahar Maritime University). Wavelengths of 510 nm for AR (A), 555 nm for RB (B), 448 nm for MO (C) and 618 nm for MG (D) were used. a MOF-PT-SPE without spiking, b MOF-PT-SPE of 10 µg/L spiked sample