UV-Vis Spectrophotometric Determination of Selected Heavy Metals (Pb, Cr, Cd and As) in Environmental, Water and Biological Samples With Synthesized Glutaraldehyde Phenyl Hydrazone As the Chromogenic Reagent. EJCHEM 2021, 2 (3), 1-5. https://doi.org/10.24018/ejchem.2021.2.3.59.