Three new Asterina species from Kodaikanal hills in Tamil Nadu

Abstract :

A simple and cost effective colorimetric spectrophotometer for determining nitrate levels in water samples has been developed. The system consists of an ultra blue LED as the light source, sample holder, a photo diode as the detector and micro controller for acquiring and processing the data. The system is working on the principle of Beer-Lambert’s law. The hardware and software details of the proposed system are presented. The stability and performance of the developed system is investigated by obtaining the calibration curve for standard nitrate solutions. The nitrate levels in water samples were also measured by the system designed and compared with the values obtained by a conventional spectrophotometer.