Physiology of Finfish and Shellfish (2+1)

Preparation of standard solution

0.0382g of NH₄Cl is dissolved in ammonia free water and is made upto 100ml. This solution contains 100 m g NH₃N/ml.1ml of chloroform may be added as preservation. Working standards of various concentrations of 100 to 500 m g NH₃^-N/litre are prepared by diluting the solution.

Water samples and different standard solutions are taken to the automatic spectrophotometer. There the concentration of ammonia (NH₃^-N)is found out using visible monochromatic light of 630nm. The standards of known centrations are used to compare and calculate the concentration of sample by using optical density.