PAR monosodium salt excellent quality manufacturer, exporter and supplier. 4-(2-Pyridylazo)resorcinol monosodium salt is a useful indicator in complexometry, as well as a reagent for the extraction and spectrophotometric determination of many transition compounds. It is a highly selective and sensitive reagent for cobalt and iron. 4-(2-Pyridylazo)resorcinol monosodium salt is also a useful reagent for selective determination of trace level chrome(III) by ion-pair reversed-phase high-performance liquid chromotography.