Quantity determination of Recorcinol compound by the Reaction with Ferric nitrate dissolved in nitric acid

By this paper we development of an analytical method to determine Recorcinol compound by coupling reaction for diazotized solution Ferric nitrate dissolved in nitric acid the presence buffer Na2HPO4 (PH= 10.8) give a with single azo dye salt having orange color soluble water high absortivity at wave length 449 nm , early study have perfect optimum condition was made determination. 
 A calibration curve range concentration (5-75)pm taken and value molar 1.5*103 L.mol-1.cm-1 relative standard divation more than 1.26% recovery 98.77% .
 Also as nature mole fraction method, from practical found that is 1:1(Recorcinol: acid) stability factor reach 1.4*106 L.mol-1 .