Separation and identification of transition metal ions by paper chromatography: improved qualitative inorganic analysis

Abstract

Paper chromatography (PC), a set of low-cost, straightforward experiments has been designed to teach the fundamentals of  chromatography to undergraduate students studying introductory inorganic chemistry. These experiments detect and separate metal  ions belonging to different groups in the analytical table. Through these PC experiments, undergraduate students will learn about the  separation and identification of metal ions from various metal salts, the comparison of color spots and retention factor values during the  separation of metal ions, the impact of alkalinity during the oxidation of metal ions, among other ideas. Paper chromatography (PC) and  planar chromatography both use immobile phases that are solid, plane surfaces. A specific type of paper is used in these experiments as  the stationary phase (Whatman quantitative grade 41 filter paper). A very small amount of sample is used for this qualitative study. Using  various eluting agents, PC may be utilized to separate, identify transition metal ions (Fe³⁺ & Cr³⁺) in the analytical group III, (Pb²⁺ &  Cu²⁺) in group II, (Co²⁺ & Ni²⁺) in group IV, (Co²⁺ & Cu²⁺) in group (IV) and group (II) and (Mo⁶⁺ & W⁶⁺) in the group VI based on their  colorful spots and retention factors (Rf) values. This qualitative study facilitated undergraduate students to realize the impact of PC to  identify and separate pair of metal ions through different color spots and their retardation factor (Rf) values.