Determination of Nitrite in Infant Rice Flour by Fluorescence Spectrophotometry
Objective:A fluorescence spectrophotometric method was established for the determination of nitrite in infant rice flour.Method:The rice flour sample was ultrasonically extracted at 60℃,and the starch in the rice flour sample was hydrolyzed at the same time.The fat and precipitated protein in the sample were removed with saturated sodium chloride solution.The activated carbon adsorption was added to eliminate the turbidity or chromaticity interference of the sample.After filtration,the supernatant was added with 2,3-diaminonaphthalene to form 2,3-naphthalene triazole.The excitation wavelength was 365 nm and the emission wavelength was 450 nm.Result:Nitrite had a good linearity in the range of 0～0.10 mg·L-1,the correlation coefficient was 0.999 6,the limit of detection and limit of quantitation were 0.028 mg·kg-1 and 0.085 mg·kg-1,respectively.The recovery rate was 94.0%～97.7%,and the relative standard deviation was 0.17%～0.84%.Conclusion:In this study,a simple,sensitive and accurate fluorescence spectrophotometry was established for the determination of nitrite content in infant rice flour.
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