Abstract:This topic adopts dual-wavelength spectrophotometry method was developed for the determination of nitrite and nitrate in foods by research.With distilled water as the reference solution,sodium nitrate standard determination of the peak is at 209 nm , sodium nitrite standard determination of the peak is at 202 nm.Through light,heating time,additive temperature,pH value, different conditions of single factor experiment and orthogonal experiment is to determine heating time, the influence of pH value, heating temperature. The results show that the best of the pH value is 7.00, the best of the heating time is 10 min, the heating temperature is 70 as the best conditions.Use ultrasonic - synergistic extraction apparatus of microwave extraction of nitrate and nitrite in the samples,with double wavelength spectrophotometry determination under the optimum condition of sample, the method detection limited is 3.695 ng/L. The relative standard deviation of nitrite in 1.15%～3.62%, the standard addition recovery of nitrite in 100.29%～102.36%, its determination result compared with national standard determination results, the relative error is in 0.01%～0.05%; relative standard deviation of nitrite in 1.57%～4.56%, the standard addition recovery of nitrite in 102.96%～106.12%.Its determination result compared with national standard determination results, the relative error is in 0.11%～6.5%.
This method is convenient, no pollution, strong anti-interference ability, can be used as a rapid detection method of nitrite and nitrate.
Keywords sodium nitrate sodium nitrite dual wavelength spectrophotometry national standard method...