4-(2-吡啶偶氮)間苯二酚單鈉鹽是一種顯色指示劑和顯色螯合劑，可用于多種金屬離子的分光光度法測定。

4-(2-吡啶偶氮)間苯二酚水合單鈉鹽已用于制備鈦試劑，勇于過氧化氫（H2O2）和超氧陰離子（O2?-）的光譜測定。它也適用于測量 Zn2+、鋅過渡金屬離子的濃度。

4-(2-Pyridylazo)resorcinol monosodium salt is a chromophoric indicator and chromogenic chelator employed for the spectrophotometric determination of several metal ions.

4-(2-Pyridylazo)resorcinol monosodium salt hydrate has been used in the preparation of titanium reagent for the spectrometric measurement of hydrogen peroxide (H2O2) and superoxide anion (O2?-). It is also suitable to measure the concentration of Zn2+, Zinc transition metal ions.