氢化物发生-原子荧光光谱法测定三种鸡蛋中硒含量的研究

Determination of Selenium in Three Kinds of Eggs by Hydride Generation Atomic Fluorescence Spectrometry

探讨氢化物发生-原子荧光光谱法测定鸡蛋中硒含量的最佳仪器工作条件,建立电热板混酸消解-氢化物发生-原子荧光光谱法检测硒含量的分析方法,并通过检测市售乌鸡蛋、土鸡蛋和普通鸡蛋中的硒含量,以期为人们进行鸡蛋消费选择提供理论实践参考。为提高原子荧光光谱法检测鸡蛋中硒含量方法的精确度和准确度,试验分别对消解液的比例、预还原剂的浓度选择、硼氢化钾的浓度等反应条件进行比较分析,并通过计算精密度、回收率、最低检出限等指标对该方法检测结果的可行性进行检验。试验结果显示:鸡蛋样品用体积比为1∶1的浓硝酸与高氯酸的混合液消解过夜后,放于200℃微控数显电热板上加热消解至透明清亮,同时将电热板温度调至160℃,当锥形瓶温度冷却至室温后,再加入5mL的6mol·L-1的盐酸进行预还原反应,再次将锥形瓶放在电热板上加热,至溶液变透明清亮后取下,冷却至室温后,将锥形瓶内溶液转移置100mL容量瓶中,加入1.00mL 10%铁氰化钾溶液,用10%盐酸定容,摇匀,待测,同时做样品空白对照。将处理后的鸡蛋样品放在高性能空心阴极硒灯下,以1.5%的硼氢化钾溶液为还原剂和2%盐酸溶液为载流液对鸡蛋样品进行连续测定。在最佳消解条件和仪器工作状态下,硒在0～8μg·L-1的浓度范围内呈现良好的线性关系,硒标准曲线方程式为IF=114.19C+1.30,标准曲线相关系数为0.999 9,最低检出限为0.01μg·L-1,相对标准偏差为0.07%～0.72%,加标回收率为96.12%～99.1%。建立了电热板混酸消解-氢化物发生-原子荧光光谱法准确测定鸡蛋中硒含量的方法,该法具有简单易操作、精密度高、灵敏性高等优点,并利用该法对普通鸡蛋、土鸡蛋和乌鸡蛋中的硒含量进行了检测分析,结果显示乌鸡蛋、土鸡蛋和普通鸡蛋的硒含量分别为0.191,0.195和0.141mg·kg-1,乌鸡蛋和土鸡蛋中的硒含量差异不显著(p>0.05),但二者的硒含量均显著高于普通鸡蛋(p<0.05)。该研究为禽蛋中硒含量的科学检测及人们进行鸡蛋消费选择提供了理论实践依据。

This paper mainly discussed the optimum conditions of hydride generation atomic fluorescence spectrometry(HG-AFS)for the determination of selenium content in eggs,then the analytical method for the determination of selenium content by mixed acid digestion hydride generation atomic fluorescence spectrometry was established,and through testing the selenium content of ordinary eggs,native eggs and dark eggs,we hoped to provide a theoretical and practical reference for people to choose eggs.In order to improve the precision and accuracy of the method to detect the selenium content in eggs by atomic fluorescence spectrometry,the mixed acid ratio,prereducing agent concentration and KBH4 concentration were compared and analyzed,and the feasibility of test result was detected by calculating the precision,recovery rate and the minimum detection limit.The results showed that the samples were dissolved overnight after the mixture of concentrated nitric acid and perchloric acid with a volume ratio of 1∶1,then heated to clear on the micro control digital display electric heating plate at 200 degrees,then the temperature of the electric heating plate was adjusted to 160 degrees,after the conical bottle temperature was cooled to room temperature,5mL of 6mol·L^-1 HCl was added.The conical bottle was heated on the electric heating plate again,and removed after the solution was clear.After cooled to the room temperature,the conical bottle solution was transferred to 100 mL capacity bottle,and 1mL 10%potassium ferricyanide solution was added,and 10%hydrochloric acid was used to shake and be measured at the same time,and the sample blank control was made at the same time.The analytes were detected by a high-performance hollow cathode selenium lamp with a deoxidizer of 1.5%KBH4 solution and the carrier fluid of 2%HCl.At the same time,the different reasons of selenium content between varieties of eggs were discussed.Under the optimum conditions and the working state,the selenium contents showed a good linear relationship in the concentration range from 0to 8g·L^-1,and the standard curve equation of selenium is IF=114.19C+1.30,and the correlation coefficient of the standard curve was 0.999 9,and the minimum detection limit was 0.01μg·L^-1,and the relative standard deviation was 0.07%~0.72%,and added standard recovery was 96.12%~99.1%.The optimum conditions of hydride generation atomic fluorescence spectrometry(HG-AFS)for the determination of selenium content in eggs were established,and the method is simple and easy to operate,with high precision and sensitivity.Using the method to test selenium content of ordinary eggs,native eggs and dark eggs,the results showed that the selenium content of dark eggs,native eggs and ordinary eggs were 0.191,0.195,0.141mg·kg^-1,respectively.The selenium content of dark eggs was not significant than that of native eggs(p >0.05),but the selenium content of dark eggs and native eggs were significantly higher than that of ordinary eggs(p<0.05).This study provides a theoretical basis for the scientific detection of selenium content in eggs and people’s choice.