Colorimetric determination of estriol hormone in bulk, pharmaceutical formulations and urine of normal and high risk pregnancy

An accurate, sensitive and selective colorimetric method for the determination of estriol hormone based on its coupling with diazotized p-amino-N-substituted banzamide and diazotized benzocaine has been developed. The red color of produced azodye is stable for at least 12 hours and exhibits an absorption maximum at 525 nm. The method has been successfully adopted for the determination of estriol in its pure form, formulated products and residues in urine of normal and high risk pregnancy. Azodye of estriol with aromatic amine was isolated and investigated by instrumental analysis and reaction pathway was proposed