Abstract
The application of nitrate ion-selective electrode was examined to establish a simple and rapid method for the routine determination of nitrate in cheese. Removal of fat and protein from the cheese suspension was carried out by heating and cooling method, followed by the aluminum resin treatment. Of the anions present in cheese, only chloride was found to affect the potential of nitrate solutions. Such interference was controlled by the use of silver resin, the treatment being carried out simultaneously with aluminum resin treatment. Potential measurements were carried out on thus prepared test solutions. Addition of known amount was used on all samples for the elimination of residual background responses. The established method was successfully applied for the nitrate determination in Samsoe, Cheddar, whey, and processed cheese, the detection limit being 5 mg of NO3/kg cheese. This method has the advantage of simplicity, rapidity, and accuracy.
