【摘要】：硒是人體必需的微量元素,與人體健康有著十分密切的關(guān)系。我國(guó)有2/3的地區(qū)屬于缺硒區(qū),曾因此發(fā)生過具有地方性特點(diǎn)的疾病—克山病,病死率高達(dá)98%。隨著人們對(duì)硒研究的深入,將硒用于防治腫瘤也取得了一定的進(jìn)展,開始提倡科學(xué)補(bǔ)硒。食品是較好的補(bǔ)硒源,但是若攝入過多也會(huì)導(dǎo)致疾病,適宜攝入范圍狹窄,因此對(duì)食品中硒的質(zhì)量分?jǐn)?shù)的測(cè)定與監(jiān)控具有重要意義。實(shí)驗(yàn)以氫化物原子熒光光譜法(hydride generation-atomic fluorescence spectrometry,簡(jiǎn)稱HG-AFS)為主要檢測(cè)方法,對(duì)AFS-9760原子熒光光度計(jì)(北京海光儀器公司)的儀器條件、氫化物發(fā)生條件、干擾的有效控制和樣品的前處理四個(gè)方面進(jìn)行了優(yōu)化,旨在建立更簡(jiǎn)單、操作性更強(qiáng)的檢測(cè)技術(shù),為恩施地區(qū)的硒資源開發(fā)利用提供技術(shù)基礎(chǔ)。主要研究結(jié)果如下:(1)以10μg/L硒標(biāo)準(zhǔn)溶液與空白溶液熒光強(qiáng)度的比值為指標(biāo),對(duì)原子熒光光度計(jì)測(cè)硒儀器條件進(jìn)行優(yōu)化。結(jié)果表明,最優(yōu)儀器條件為:燈電流80mA,載氣流量300mL/min,負(fù)高壓300V。(2)以10μg/L硒標(biāo)準(zhǔn)溶液熒光強(qiáng)度為指標(biāo),對(duì)氫化物發(fā)生條件進(jìn)行響應(yīng)面實(shí)驗(yàn)。通過Design Expert8.0分析建立了10μg/L硒標(biāo)準(zhǔn)溶液熒光強(qiáng)度與各因素的回歸模型:Y=-2347.28203+455.96454A+223.51020B+239.16170C+3.10955AB+5.62614 A C-22.06463A2-19.54899B2-23.20035C2,其中,A為硼氫化鉀濃度;B為載流鹽酸濃度;C為介質(zhì)鹽酸濃度。得到的最優(yōu)反應(yīng)條件為:硼氫化鉀濃度12g/L、載流鹽酸濃度和介質(zhì)鹽酸濃度為7%。(3)對(duì)原子熒光光度計(jì)測(cè)硒時(shí)的干擾進(jìn)行消除。實(shí)驗(yàn)結(jié)果表明,當(dāng)加入1.2mL 100g/L氨基磺酸溶液時(shí),被亞硝根離子抑制的20μg/L硒標(biāo)準(zhǔn)溶液的熒光信號(hào)可完全恢復(fù)。另外,共存元素中Cu2+對(duì)硒的測(cè)定是負(fù)干擾,Pb2+對(duì)硒的測(cè)定是正干擾,實(shí)驗(yàn)采用鐵氰化鉀作為掩蔽劑可消除影響,當(dāng)加入1m L 10%鐵氰化鉀溶液后可容許10000倍Cu2+和Pb2+。(4)分別對(duì)樣品微波消解和普通濕法消解的處理?xiàng)l件進(jìn)行優(yōu)化。0.1g、0.5g、1g樣品微波消解條件分別為:5mL 40%硝酸200℃保溫15min、5mL硝酸180℃保溫15min和10mL硝酸160℃保溫20min,微波消解完后放在趕酸器上進(jìn)行預(yù)還原,對(duì)應(yīng)條件分別為:2mL鹽酸160℃加熱15min、3mL鹽酸160℃加熱30min(1g樣品與0.5g一致)。0.1g樣品采用普通濕法消解,條件為加入4mL硝酸和1mL高氯酸在160℃消解至1-2mL后加入4mL50%鹽酸進(jìn)行還原。(5)采用原子熒光光譜法、熒光法和鄰苯二胺法對(duì)優(yōu)化后的微波消解條件處理的食品樣品進(jìn)行硒的測(cè)定。結(jié)果表明,將國(guó)標(biāo)中的微波消解方法和優(yōu)化得到的微波消解方法處理樣品進(jìn)行比較,除豇豆外,同一檢測(cè)方法測(cè)得的樣品中硒的質(zhì)量分?jǐn)?shù)差異在10%以內(nèi),所以優(yōu)化后的微波消解操作方法同樣適用于熒光法和鄰苯二胺法。另外,當(dāng)樣品中硒的質(zhì)量分?jǐn)?shù)大于2μg/g時(shí),鄰苯二胺法測(cè)得的樣品中硒的質(zhì)量分?jǐn)?shù)與原子熒光光譜法和分子熒光法差異在10%以內(nèi)。
[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，

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