A few of these methods are requiring complicated and expensive equipments and a few of them are also involving extraction procedures and obviously limiting the practice of such methods in common laboratories. In this background and like earlier phosphate method from here it is attempted again to develop a simple and straight forward, spectrophotometric method for phosphate but with the reducing agent thiourea. Since thiourea is commercially available, economically cheaper, known for good shelf stability and already used as a preservative in phosphate determination along with the reducing agent,
o-phenylenediamine dihydrochloride