HG-AFS测定食品中硒元素的因素优化及干扰控制
发布时间：2018-11-06 16:45
【摘要】：硒是人体必需的微量元素,与人体健康有着十分密切的关系。我国有2/3的地区属于缺硒区,曾因此发生过具有地方性特点的疾病—克山病,病死率高达98%。随着人们对硒研究的深入,将硒用于防治肿瘤也取得了一定的进展,开始提倡科学补硒。食品是较好的补硒源,但是若摄入过多也会导致疾病,适宜摄入范围狭窄,因此对食品中硒的质量分数的测定与监控具有重要意义。实验以氢化物原子荧光光谱法(hydride generation-atomic fluorescence spectrometry,简称HG-AFS)为主要检测方法,对AFS-9760原子荧光光度计(北京海光仪器公司)的仪器条件、氢化物发生条件、干扰的有效控制和样品的前处理四个方面进行了优化,旨在建立更简单、操作性更强的检测技术,为恩施地区的硒资源开发利用提供技术基础。主要研究结果如下:(1)以10μg/L硒标准溶液与空白溶液荧光强度的比值为指标,对原子荧光光度计测硒仪器条件进行优化。结果表明,最优仪器条件为:灯电流80mA,载气流量300mL/min,负高压300V。(2)以10μg/L硒标准溶液荧光强度为指标,对氢化物发生条件进行响应面实验。通过Design Expert8.0分析建立了10μg/L硒标准溶液荧光强度与各因素的回归模型:Y=-2347.28203+455.96454A+223.51020B+239.16170C+3.10955AB+5.62614 A C-22.06463A2-19.54899B2-23.20035C2,其中,A为硼氢化钾浓度;B为载流盐酸浓度;C为介质盐酸浓度。得到的最优反应条件为:硼氢化钾浓度12g/L、载流盐酸浓度和介质盐酸浓度为7%。(3)对原子荧光光度计测硒时的干扰进行消除。实验结果表明,当加入1.2mL 100g/L氨基磺酸溶液时,被亚硝根离子抑制的20μg/L硒标准溶液的荧光信号可完全恢复。另外,共存元素中Cu2+对硒的测定是负干扰,Pb2+对硒的测定是正干扰,实验采用铁氰化钾作为掩蔽剂可消除影响,当加入1m L 10%铁氰化钾溶液后可容许10000倍Cu2+和Pb2+。(4)分别对样品微波消解和普通湿法消解的处理条件进行优化。0.1g、0.5g、1g样品微波消解条件分别为:5mL 40%硝酸200℃保温15min、5mL硝酸180℃保温15min和10mL硝酸160℃保温20min,微波消解完后放在赶酸器上进行预还原,对应条件分别为:2mL盐酸160℃加热15min、3mL盐酸160℃加热30min(1g样品与0.5g一致)。0.1g样品采用普通湿法消解,条件为加入4mL硝酸和1mL高氯酸在160℃消解至1-2mL后加入4mL50%盐酸进行还原。(5)采用原子荧光光谱法、荧光法和邻苯二胺法对优化后的微波消解条件处理的食品样品进行硒的测定。结果表明,将国标中的微波消解方法和优化得到的微波消解方法处理样品进行比较,除豇豆外,同一检测方法测得的样品中硒的质量分数差异在10%以内,所以优化后的微波消解操作方法同样适用于荧光法和邻苯二胺法。另外,当样品中硒的质量分数大于2μg/g时,邻苯二胺法测得的样品中硒的质量分数与原子荧光光谱法和分子荧光法差异在10%以内。
[Abstract]:Selenium is a necessary trace element in human body and has a very close relationship with human health. Two thirds of the regions in China belong to selenium deficiency area, which has caused Keshan disease with endemic characteristics, and the mortality is as high as 98%. With the development of selenium research, some progress has been made in the application of selenium to cancer prevention and treatment, and scientific supplementation of selenium has been advocated. Food is a good source of selenium supplementation, but excessive intake can also lead to disease, and the suitable range of intake is narrow. Therefore, it is of great significance to determine and monitor the content of selenium in food. In this experiment, hydride atomic fluorescence spectrometry (HG-AFS) was used as the main detection method. The instrument conditions and hydride generation conditions of AFS-9760 atomic fluorescence photometer (Beijing Haiguang instrument Company) were studied. The effective control of interference and the pretreatment of samples were optimized in order to establish a simpler and more operable detection technology and to provide a technical basis for the exploitation and utilization of selenium resources in Enshi area. The main results are as follows: (1) with the ratio of fluorescence intensity of 10 渭 g / L selenium standard solution to blank solution as the index, the instrument conditions for the determination of selenium by atomic fluorescence photometer are optimized. The results show that the optimal instrument conditions are as follows: lamp current 80 Ma, carrier gas flow rate 300 mL / min, negative high voltage 300 V. (2) taking 10 渭 g / L selenium standard solution fluorescence intensity as the index, the reaction surface test of hydride generation condition is carried out. A regression model of fluorescence intensity and various factors of 10 渭 g / L selenium standard solution was established by Design Expert8.0 analysis: YP2347.28203 455.96454A 223.51020B 239.16170C 3.10955AB 5.62614 A C-22.06463A2-19.54899B2-23.20035C2, A is the concentration of potassium borohydride; B is current carrying hydrochloric acid concentration, C is medium hydrochloric acid concentration. The optimum reaction conditions are as follows: potassium borohydride concentration 12 g / L, current carrying hydrochloric acid concentration and medium hydrochloric acid concentration 7. (3) the interference in the determination of selenium by atomic fluorescence photometer is eliminated. The experimental results show that the fluorescence signal of the 20 渭 g / L selenium standard solution inhibited by nitrite ion can be completely recovered when the 1.2mL 100g/L amino sulfonic acid solution is added. In addition, the determination of selenium by Cu2 in coexisting elements is a negative interference, and the determination of selenium by Pb2 is a positive interference. The effect can be eliminated by using potassium ferricyanide as a masking agent. When adding 1m L 10% potassium ferricyanide solution, 10000 times Cu2 and Pb2 can be allowed. (4) the treatment conditions of microwave digestion and wet digestion of samples are optimized, respectively. The microwave digestion conditions of 1g samples were as follows: 5mL 40% nitric acid was heated at 200 鈩，
本文编号：2314866
[Abstract]:Selenium is a necessary trace element in human body and has a very close relationship with human health. Two thirds of the regions in China belong to selenium deficiency area, which has caused Keshan disease with endemic characteristics, and the mortality is as high as 98%. With the development of selenium research, some progress has been made in the application of selenium to cancer prevention and treatment, and scientific supplementation of selenium has been advocated. Food is a good source of selenium supplementation, but excessive intake can also lead to disease, and the suitable range of intake is narrow. Therefore, it is of great significance to determine and monitor the content of selenium in food. In this experiment, hydride atomic fluorescence spectrometry (HG-AFS) was used as the main detection method. The instrument conditions and hydride generation conditions of AFS-9760 atomic fluorescence photometer (Beijing Haiguang instrument Company) were studied. The effective control of interference and the pretreatment of samples were optimized in order to establish a simpler and more operable detection technology and to provide a technical basis for the exploitation and utilization of selenium resources in Enshi area. The main results are as follows: (1) with the ratio of fluorescence intensity of 10 渭 g / L selenium standard solution to blank solution as the index, the instrument conditions for the determination of selenium by atomic fluorescence photometer are optimized. The results show that the optimal instrument conditions are as follows: lamp current 80 Ma, carrier gas flow rate 300 mL / min, negative high voltage 300 V. (2) taking 10 渭 g / L selenium standard solution fluorescence intensity as the index, the reaction surface test of hydride generation condition is carried out. A regression model of fluorescence intensity and various factors of 10 渭 g / L selenium standard solution was established by Design Expert8.0 analysis: YP2347.28203 455.96454A 223.51020B 239.16170C 3.10955AB 5.62614 A C-22.06463A2-19.54899B2-23.20035C2, A is the concentration of potassium borohydride; B is current carrying hydrochloric acid concentration, C is medium hydrochloric acid concentration. The optimum reaction conditions are as follows: potassium borohydride concentration 12 g / L, current carrying hydrochloric acid concentration and medium hydrochloric acid concentration 7. (3) the interference in the determination of selenium by atomic fluorescence photometer is eliminated. The experimental results show that the fluorescence signal of the 20 渭 g / L selenium standard solution inhibited by nitrite ion can be completely recovered when the 1.2mL 100g/L amino sulfonic acid solution is added. In addition, the determination of selenium by Cu2 in coexisting elements is a negative interference, and the determination of selenium by Pb2 is a positive interference. The effect can be eliminated by using potassium ferricyanide as a masking agent. When adding 1m L 10% potassium ferricyanide solution, 10000 times Cu2 and Pb2 can be allowed. (4) the treatment conditions of microwave digestion and wet digestion of samples are optimized, respectively. The microwave digestion conditions of 1g samples were as follows: 5mL 40% nitric acid was heated at 200 鈩，
本文编号：2314866
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