Diethyldithiophosphate (DDTP): A Review on Properties, General Applications, and Use in Analytical Spectrometry

The compound O,O-diethyldithiophosphate, also known as diethyldithiophosphate or DDTP, is employed in a variety of applications, from organic synthesis to extraction/separation of metals in preconcentration procedures. This reagent gained importance especially after preliminary investigations dated from the 1960s, which demonstrated its high stability in acidic medium and high selectivity and efficiency in complex formation reactions with metals and metalloids. The presence of two sulfur atoms and one phosphorus atom in the DDTP molecule turns this bidentate ligand into a versatile chelating agent, allowing the formation of complexes with a number of different geometric arrangements. In addition to the fact that the synthesis of DDTP is simpler in comparison to those of other dithiophosphates, it possesses other advantageous characteristics such as relatively low toxicity, high solubility in aqueous medium, high extraction efficiency from organic to aqueous media, and high redox potential. This review will summarize the main characteristics of DDTP, including some historical facts and information on its synthesis, structure, and toxicity, as well as other characteristics and numerous application examples. Special attention will be given to the reported analytical methods that use DDTP as a complexing agent in preconcentration procedures prior to analyte determination using spectrometric techniques.