摘要:本课题采用国标法，微波法及超声—微波协同萃取法这三种提取方法提取蔬菜中亚硝酸盐，并对提取条件进行了单因素和正交实验。实验确定料液比、功率、时间对微波法的影响以及料液比、功率、时间、温度、提取剂和活性炭加入量对超声—微波协同萃取法的影响。结果表明，超声—微波协同萃取法提取效果最优，反应料液比为1:15，反应时间为6 min，反应功率为50 w为其最佳实验条件，可用于实际样品中亚硝酸盐的提取。
用超声—微波协同萃取法在最佳条件下对样品进行测定，其测定结果与国标和微波法测定结果相比较，提取率分别增加了61.40%~95.73%和23.58%~32.10%。测定的相对标准偏差为1.04%~4.52%，加标回收率在97.28%~104.76%之间。用实际样品进行测定，测得的7种叶类蔬菜中亚硝酸盐含量在1.3643~1.7708 mg/kg之间，均在亚硝酸盐限量卫生标准所规定的范围之内。
关键词 亚硝酸盐；国标法；微波法；超声—微波协同萃取法
Abstract:The topic uses national standard method, microwave method and ultrasonic-microwave extraction method to extract nitrite in vegetables, through single factors and orthogonal experiments to determine the influence of the material liquid ratio, power, time on microwave method and the influence of the material liquid ratio, power, time, temperature, extraction reagent and the amount of activated carbon on ultrasound-microwave collaborative extraction method. Results show that the material liquid ratio of 1:15 and reaction time of 6 min and reaction power of 50w are the best experimental conditions, which can be used to extract nitrite in actual samples.
Using ultrasonic-microwave collaborative extraction method to test samples under the best conditions, the relative standard deviation is between 1.04% and 1.04%, standard addition recovery rate is between 97.28% and 104.76%. When compared with national standard method and microwave method, extraction yield increases by 61.40% ~ 95.73% and 23.58% ~ 61.40% respectively. Meanwhile, nitrite tested in vegetables is between 1.3643 and 1.7708 mg/kg, which are all under control of standards.
Keywords nitrite the national standard extraction method the microwave method the ultrasonic-microwave collaborative extraction method
