Figure 4From: Salicylic acid functionalized silica-coated magnetite nanoparticles for solid phase extraction and preconcentration of some heavy metal ions from various real samplesFT-IR spectra (a) salicylic acid (b) Fe 3 O 4 nanoparticles (c) SiO 2 coated Fe 3 O 4 nanoparticles (d) SiO 2 coated Fe 3 O 4 nanoparticles modified with salicylic acid.Back to article page