微波消解-氢化物发生-原子荧光法测定海蜇中的痕量砷和硒

建立了氢化物发生-原子荧光光谱法(HG-AFS)测定新鲜和腌制海蜇中痕量砷、硒的分析方法。采用冷冻干燥和微波消解相结合的方法处理样品,设定了最佳的样品处理条件和仪器测定条件,解决了消解液中过剩酸对测定的干扰问题,并对共存元素干扰情况进行了研究。利用加标回收试验,对分析方法进行了验证。实验结果表明,该方法具有简便、快速、灵敏、准确等特点,适合于含水量较高的生物样品的测定。     

微波消解ICP-MS法测定根和根茎类生药中11种微量元素

建立了微波消解技术ICP-MS法测定了根及根茎类生药中的铬、锰、镍、钴、铜、锌、砷、硒、钼、镉和铅11种微量元素的方法。对同时适用于两类生药的各微量元素分析的前处理方法进行了研究,从消解体系、酸用量、消解程序等几方面对微波消解条件进行了优化,为同类生药的消解提供了参考。方法检出限为0.001～0.260 μg·g-1,相对标准偏差为0.4%～3.1%,回收率为90%～110%。     

微波消解石墨炉原子吸收光谱法测定水产品中痕量铍

采用微波制样技术,用石墨炉原子吸收光谱法测定水产品中痕量铍。方法的线性范围为0-10μg·L-1,检出限为0．076 ng·g-1,相对标准偏差为2．7％,回收率为97．0％。方法准确、快速、简便,并与常压消解法的结果比较,基本一致,已用于水产品中痕量铍的测定。     

微波消解凯氏定氮法快速测定酱油中全氮

研究了凯氏定氮法测定酱油中全氮时样品的微波消解方法,进行了微波消解条件的选择及消解结果精密度试验,并与国家标准方法对比,验证了方法的准确度。试验结果表明,消解完全仪需20min,相对标准偏差均小于2%（n=7）,回收率范围为96%～103%,经t检验,微波溶样法与国家标准凯氏定氮法的测定结果无显著性差异。     

动能歧视(KED)-电感耦合等离子体质谱(ICP-MS)法测定贵州沉积型稀土矿中16种稀土元素

贵州沉积型稀土矿主要含有高岭土-锐钛矿石等矿物,存在高含量Si、Al、Fe、Ti、Zr等难溶基体元素,采用高压密闭微波消解法处理难以将其完全溶解,易使测定结果偏低,需再次消解或进一步电热板敞开酸溶处理,方法耗时长,不利于大批量样品检测需求。同时电感耦合等离子体质谱法(ICP-MS)在测定稀土元素时存在基体效应和质谱干扰,影响了检测数据的准确性。本文采用过氧化钠熔融分解样品,熔融物冷却后引入三乙醇胺溶液,在碱性溶液中,大量基体元素与三乙醇胺形成稳定配合物,并与大量溶剂钠盐存于溶液中,稀土元素与Ca、Mg、Sr、Ba等留存于沉淀,经过滤,实现稀土元素与大量基体元素分离,随后沉淀用(1+1)硝酸复溶,并以103Rh和185Re为在线注入内标协同降低基体干扰;启用动能歧视(KED)模式以降低测定过程中潜在的质谱干扰。实验结果表明:高压密闭微波消解法消解液浑浊有残渣,溶矿耗时长,测试结果偏低,碱溶法酸化后溶液清亮透明,稀土元素测定值准确性高;经条件试验,采用10%三乙醇胺溶液提取能较大降低基体干扰;启用KED模式可降低测定过程中的质谱干扰,且准确度优于STD模式;碱溶法方法检出限为0.008μg/g~0.049μg/g,测定下限为0.034μg/g~0.195μg/g,相对标准偏差RSD在0.78%～10.2%之间,相对误差RE在0.0225%~13.5%之间。经实际样品验证,碱熔法较适用于贵州沉积性稀土矿中16种稀土元素的测定。     

灰化消解-极谱法测定油料中五个重金属元素

建立了灰化消解-极谱法测定油样中镉、铅、铜、镍、钴等5种微量重金属元素的含量.油料样品通过灰化法消解后,用极谱法在乙酸-乙酸盐缓冲溶液和磺基水杨酸-磷酸-氨水体系中测定5种重金属元素的含量.5种微量重金属元素的检出限为1.3×10-4～9.8×10-4 g·L-1,加标回收率为90%～106%,相对标准偏差为0.22%～3.16%.     

钛铁矿中钛的测定

利用钛铁矿能显著吸收微波的介电特性,采用家用微波炉,在微波辐照下,用浓磷酸消解矿样,并用氧化还原滴定法测定钛的含量,试验结果表明,该方法能快速分解矿样,测定结果准确,与传统分析方法比较,该法具有简便、快速、低耗、适应大批量样品分析等优点。还对钛铁矿的结构作了X-射线衍射分析。     

In Vitro Inhibitory Effects of Viburnum opulus Bark and Flower Extracts on Digestion of Potato Starch and Carbohydrate Hydrolases Activity

One of the effective treatments for diabetes is to reduce and delay the absorption of glucose by inhibition of α-amylase and α-glucosidase in the digestive tract. Currently, there is a great interest in natural inhibitors from various part of plants. In the present study, the phenolic compounds composition of V. opulus bark and flower, and their inhibitory effects on in vitro potato starch digestion as well as on α-amylase and α-glucosidase, have been studied. Bark and flower phenolic extracts reduced the amount of glucose released from potato starch during tree-stage simulated digestion, with IC₅₀ value equal to 87.77 µg/mL and 148.87 µg/mL, respectively. Phenolic bark extract showed 34.9% and 38.4% more potent inhibitory activity against α-amylase and α-glucosidase, respectively, but the activity of plant extracts was lower than that of acarbose. Chlorogenic acid (27.26% of total phenolics) and (+)-catechin (30.48% of total phenolics) were the most prominent phenolics in the flower and bark extracts, respectively. Procyanidins may be responsible for the strongest V. opulus bark inhibitory activity against α-amylase, while (+)-catechin relative to α-glucosidase. This preliminary study provides the basis of further examination of the suitability of V. opulus bark compounds as components of nutraceuticals and functional foods with antidiabetic activity.     

Comparing Efficiency of Lysis Buffer Solutions and Sample Preparation Methods for Liquid Chromatography–Mass Spectrometry Analysis of Human Cells and Plasma

The use of a proper sample processing methodology for maximum proteome coverage and high-quality quantitative data is an important choice to make before initiating a liquid chromatography–mass spectrometry (LC–MS)-based proteomics study. Popular sample processing workflows for proteomics involve in-solution proteome digestion and single-pot, solid-phase-enhanced sample preparation (SP3). We tested them on both HeLa cells and human plasma samples, using lysis buffers containing SDS, or guanidinium hydrochloride. We also studied the effect of using commercially available depletion mini spin columns before SP3, to increase proteome coverage in human plasma samples. Our results show that the SP3 protocol, using either buffer, achieves the highest number of quantified proteins in both the HeLa cells and plasma samples. Moreover, the use of depletion mini spin columns before SP3 results in a two-fold increase of quantified plasma proteins. With additional fractionation, we quantified nearly 1400 proteins, and examined lower-abundance proteins involved in neurodegenerative pathways and mitochondrial metabolism. Therefore, we recommend the use of the SP3 methodology for biological sample processing, including those after depletion of high-abundance plasma proteins.     

Electronic Simulation of Neutronic Transient Studies for PWR-900 MW(e)

To study different functionalities of the PWR-900 MW(e) reactor core, an electronic model of Simulation Program with Integrated Circuit Enfesied (PSPICE) for electronic circuit design was adopted to model the mathematical models. A classical breadboard electronically simulates the physical terminal characteristics of each network. The electronic simulator, parity simulator, for reactor core can simulate six-delayed neutron groups, single prompt neutron, neutron source, fuel channel, the coolant, reactor poisons, temperature feedback, control rods, safety rods, and boron injection. Positive/negative step or sin reactivity functions are two case studies were analyzed. The obtained results were found to be in a good agreement with the available data of El-Dabaa PWR 900 MW(e) basic simulator.