The validation of nitrite and nitrate analysis methods in bread using p-aminobenzoic acid (PABA) via UV-VIS spectrophotometry

In this research, the validation of nitrite and nitrate analysis methods on bread samples using p-aminobenzoic acid (PABA) through UV-Vis Spectrophotometry was done. The objective is to obtain the optimum conditions for nitrite and nitrate analysis by UV-Vis spectrophotometry and to apply nitrite and nitrate analysis methods that meet the parameters of the method validation. The study begins by determining the optimum conditions for nitrite analysis, while nitrates need to be reduced to be analyzed by UV-Vis spectrophotometry using Zn powder. Then the analysis method is validated based on the method validation parameters and then applied to measure nitrite and nitrate levels in bread samples. Based on the method used with specific optimum conditioning, it is estimated that the diazotization reaction produces an azo compound which has a wavelength of 500-600 nm. The results of the validation of the nitrite and nitrate analysis methods reduced using Zn powder have the linearity of the method with the square of R>0.98 in the range 0-1 mg L−1. The molar absorptivity for nitrite and nitrate is 3.37×104 and 2.91×104 L mol−1 cm−1, and the detection limit is 4.29×10-3 and 9.34×10-3 mg L-1. The result of %RSD of nitrite and nitrate is estimated to be in the range of 0.30-1.82%, while the %recovery of nitrite and nitrate is in the range of 83-101.4%. Nitrites and nitrates contained in bread samples are estimated not to exceed quality standards, according to the RI Minister of Health Regulation No. 1168 / Menkes / Per / X / 1999.