普通模式与八极杆碰撞/反应池电感耦合等离子体质谱法测定大米中痕量硒和铬的比较

目的 建立使用八级杆碰撞/反应池电感耦合等离子体质谱法测定大米中痕量铬和硒元素含量的方法,比较普通模式和ORS模式对2种元素测定结果的差异。方法 ORS模式采用屏蔽矩技术结合氦气碰撞反应池消除40Ar12C+ 对52Cr、39Ar39Ar+和40Ar38Ar+对78Se的干扰,选用丰度较高的同位素52Cr、78Se测定。普通模式通过在线加入内标校正基体干扰,选择同量异位素干扰较少的同位素53Cr、82Se测定。结果 普通模式铬和硒元素的检出限为0.059μg/L和0.023μg/L,而ORS模式铬和硒的检出限为0.027μg/L和0.012μg/L,铬、硒元素的含量在0 ～ 100μg/L范围内,线性相关系数优于0.9998。结论 普通模式用于大米中含量较高的铬和硒的测定也是可行的,应用ORS模式在痕量样品分析时测定结果更准确可靠,研究结果为同类样品的测定提供了参考     

Synthesis of scalable 1T/2H–MoSe2 nanosheets with a new source of Se in basic media and study of their HER activity

In this report MoSe₂ nanosheets were fabricated using new precursors of MoCl₅ and Na₂SeO₃ and a very simple chemical procedure without using inert atmosphere and complex methods for preparing Se ion source. The structural properties of fabricated nanosheets were examined by means of XRD, field emission scanning electron microscopy (FESEM), elemental mapping of energy dispersive x-ray spectroscopy (EDS), transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectroscopy and isotherm gas adsorption-desorption technique. The results showed the nanosheets are mixed phase metallic-semiconductor 1T-2H with thicknesses about 3.6–6.1 nm and are stable for several months. The effective surface area is obtained 28 m² g⁻¹ and mean pore size of 6–8 nm for MoSe₂ nanosheets. Electro-impedance spectroscopy showed low resistivity of nanosheets due to presence of metallic phase of MoSe₂. HER activity of nanosheets obtains a Tafel slope of 60 mV.dec⁻¹ and high current density values up to 150 mA cm⁻² and the value of over potential at 10 mA cm⁻² is 155 mV.     

富硒酵母的研究进展

本文综述硒的生理功能和富硒酵母的生产,同时概括了富硒酵母生产中的一些影响因素及茵种的选育。     

Determination of ultratrace levels of selenium in fruit and vegetable samples grown and consumed in Portugal

The selenium content in fruit and vegetable samples from two regions in Portugal were analysed using hydride generation atomic fluorescence spectrometry (HG-AFS) and radiochemical nuclear activation analysis (RNAA) – two analytical methods with very low limits of detection. The lower detection limits of HG-AFS, 3 μg kg⁻¹ and 8 μg kg⁻¹ (according to conditions used for digestion), and for RNAA, 10 μg kg⁻¹, meant that it was possible to determine selenium in samples previously analysed using the replicate sample instrumental nuclear activation analysis (RSINAA) with a higher detection limit associated.     

Effect of foliar application of selenium on its uptake and speciation in carrot

Carrot (Daucus carota) shoots were enriched by selenium using foliar application. Solutions of sodium selenite or sodium selenate at 10 and 100 μg Se ml⁻¹, were sprayed on the carrot leaves and the selenium content and uptake rate of selenium were estimated by ICP–MS analysis. Anion and cation exchange HPLC were tailored to and applied for the separation of selenium species in proteolytic extracts of the biological tissues using detection by ICP–MS or ESI–MS/MS. Foliar application of solutions of selenite or selenate at 100 μg Se ml⁻¹ resulted in a selenium concentration of up to 2 μg Se g⁻¹ (dry mass) in the carrot root whereas the selenium concentration in the controls was below the limit of detection at 0.045 μg Se g⁻¹ (dry mass). Selenate-enriched carrot leaves accumulated as much as 80 μg Se g⁻¹ (dry mass), while the selenite-enriched leaves contained approximately 50 μg Se g⁻¹ (dry mass). The speciation analyses showed that inorganic selenium was present in both roots and leaves. The predominant metabolised organic forms of selenium in the roots were selenomethionine and γ-glutamyl-selenomethyl-selenocysteine, regardless of which of the inorganic species were used for foliar application. Only selenomethionine was detected in the carrot leaves. The identity of selenomethionine contained in carrot roots and leaves was successfully confirmed by HPLC–ESI–MS/MS.     

长寿地区大米中硒的有机形态及其生物利用度研究

为了探究典型长寿区大米有机硒的赋存形态与人体硒营养水平的关系,本文分析了江西典型长寿区大米中有机硒、谷蛋白硒、硒代蛋氨酸（Selenomethionine, SeMet）等的组成特征,并运用胃肠体外模拟法对大米硒的生物可利用度及其与各有机硒组分之间的相关关系进行了研究。结果表明,大米中的硒主要以有机形式（78.67 ± 13.52%）赋存,其中,53.73 ± 8.27%的有机硒为谷蛋白硒,且65%以上的谷蛋白硒可酶解消化为SeMet。大米硒的生物可利用度为55.58 ± 10.53%。大米谷蛋白中SeMet比例相对较高且易于被人体吸收利用,这可能与当地居民的健康长寿关系密切。不过,SeMet与大米可利用硒的相关系数仅为0.55。因此,未来有必要对大米中不同硒蛋白的代谢产物（如SeMet）进行研究。     

基于BDD 的自动化测试框架研究

敏捷开发模式的盛行掀起了自动化测试的一轮热潮,测试和开发合作越来越密切。本文研究的自动化测试框 架,将BDD 的敏捷开发理念与软件测试相融合,通过统一的Gherkin 语言定义验收测试标准,帮助业务人员、测试人员和开发 人员形成对需求明确统一的认识,然后通过web driver 测试代码实现可执行的验收测试,以TDD 的方式实现产品代码。该框 架使用Specflow、Selenium 和MsTest 等测试工具,真正实现了自动化测试,大大减少了手工测试的压力,促进开发测试过程中 软件开发涉众之间的沟通,及时得到用户反馈,满足快速发布产品的需求,提升产品质量。     

Diffraction efficiency change in PVA/AA photopolymer films by photosensitive inorganic compound addition

The highest diffraction efficiency (DE) value after illumination and post-curing of photopolymer films were obtained at the SeO₂/Acrylamide (AA) Ratios of AA 3.0 g, SeO₂ 1.0 g and the DE’s were stable values of over 90%. By the addition of SeO₂, the maximum DE at the initial stage of illumination was reached at 300 seconds, which suggests SeO2 slows down the photopolymerization of. DE variation curve for the optimum composition during extendedtime illumination of 9,000 seconds resembles a sine curve due to the combination of the monomer diffusion and the photopolymerization, and the photopolymer film expanded at about 8% after photopolymerization due to monomer migration.     

HPLC-ICP-MS法分析测定富硒保健品中的硒形态

确定保健品中硒形态(亚硒酸根、硒酸根),采用水浴振荡提取的前处理方法,液相色谱柱选用IonPac AS11(250 mm×4 mm)分析柱+IonPac AG11(50 mm×4 mm)保护柱,对其进行分离,ICP-MS检测。本文探讨色谱柱、流动相、样品前处理方法的选择,并且在液体、胶囊、鱼油、片状保健品中进行加标回收实验,亚硒酸根、硒酸根的回收率为79.7%-116.4%,精密度(RSD)小于15%。该方法具有灵敏度高、干扰小、样品前处理简单等优点,可以用于保健品中硒形态的筛查和测定。