Method And Application Of Detection Of Nitrite In Pickled Vegetables

According to the principle of fluorescence reaction between nitrite and 2,3-Diaminonaphthalene,the method was established to detect the content of nitrite in pickled vegetables by high performance liquid chromatography(HPLC-FLD).The advantages of this method were sensitivity,low detection limit and strong anti-interference ability.Meanwhile,we use this method to detect the content of nitrite in pickled vegetables of Handan area and analysis the risk situation of nitrite.The results were as follows:1.Bath derived conditions: the temperature was 40? and the time was 20min;Liquid chromatography conditions:the low rate of mobile phase acetonitrile-water(40+60)was 0.8m L/min;Fluorescence detector(wavelength): the excitation wavelength was 375 nm and the emission wavelength was 415 nm.According to the results of verification,the linear range was 0~0.4mg/L and the correlation coefficient was 0.9993.The detection limit can reach to 0.01mg/kg which was lower than the national standard detection limit(1mg/kg).The average recovery rate was 80%~95.8% and the relative standard deviation was 0.5~15.1%.2.The measurement uncertainty was evaluated by detecting the nitrite content of pickled mustard tuber.The detection result was(0.30±0.07)mg/kg,k=2.Three main uncertainty sources were as follows:(1)The uncertainty of the introduction of the sample quality;(2)The uncertainty of the introduction of the volume of constant volume;(3)The uncertainty of the introduction of concentration measurement,including the standard solution and calibration curve.The sample quality and volume had great influence on the measurement results.3.According to the actual application and the uncertainty results,we assign the reliability detection limit of the method was 0.1mg/kg.The nitrite detection rate of the pickled vegetables in Handan area was 94%,and the qualified rate was 99.6%.The risk situation of pickled vegetables nitrite Handan was in low level.There were different nitrite content among different types of pickled vegetables.The mustard pickled vegetable was relatively high.The content of sweet and sour products was significantly lower than other types.