离子色谱法检测人体营养补充液中阴阳离子和有机酸

本文介绍了一种采用抑制型电导检测器的离子色谱法检测人体营养补充液中阴阳离子和有机酸的方法。选择的色谱条件为:(1)阴离子,IonPac AS23阴离子交换柱,淋洗液自动发生装置在线产生KOH梯度淋洗,抑制型电导检测;(2)阳离子,IonPac CS12A阳离子色谱交换柱,甲烷磺酸等度淋洗,抑制型电导检测。将人体营养补充液样品稀释一定倍数后分别直接进样分析,检测了低至低μg/L级(以溶液计)的阴阳离子。该方法对十种阴阳离子的检出限(S/N=3)从3．6到59．0μg/L,线性范围均跨越两个数量级以上,线性相关系数r为0．9988～0．9999,连续11次进样RSD值小于4%,加标回收率在94．6%～103．9%之间,用于实际样品的检测,结果令人满意。     

Mg-3Zn-0.5Zr合金在含有不同离子的模拟生理环境中的降解机理

采用电化学测试（极化曲线,开路电位,电化学阻抗谱）研究了Mg-3Zn-0.5Zr合金在四中侵蚀性离子（cl-,HPO42-,HCO3-和SO42-）相互作用下的降解行为。我们发现cl-会导致合金发生多孔状点蚀,腐蚀坑在表面扩展并加深。HPO42-能降低合金降解速率抑制点蚀。Mg-3Zn-0.5Zr合金在含有HCO3-离子的溶液中腐蚀行为是早期HCO3-离子大大加快了镁合金的腐蚀降解速率,但由于能够在剧烈腐蚀部位诱导钝化,对合金点蚀的扩展具有抑制作用。SO42-离子也能腐蚀合金,但在生理环境中浓度低,所以SO42-离子对合金腐蚀降解的行为加速不明显。这些结果加深了我们对Mg-3Zn-0.5Zr合金在生理环境中降解机理的认识。     

一种测定硫酸根的直接分光光度法

新偶氮染料１,３－Ｎ,Ｎ′－双－［４－（４′－硝基苯偶氮）苯基］异方酸二酰胺（ＢＮＢＰＳ）的ＤＭＳＯ溶液与适量水所构成的体系是硫酸根的良好显色剂（Δλ＝１０２ｎｍ）。显色剂与硫酸根在ｐＨ４．３～７．５范围内发生反应,迅速由红色变为蓝色。λｍａｘ＝６３２ｎｍ,ε６３２＝４×１０４Ｌ·ｍｏｌ－１·ｃｍ－１,测定硫酸根的线性范围为０～１５μｇ／１０ｍＬ。考察了常见离子的干扰情况,提供了一种新的测定硫酸根的直接分光光度法,用于测定水样中的硫酸根含量,结果满意。     

水滑石类吸附剂的研究进展

水体中阴离子类污染物引起人们广泛注意,近年来,水滑石类化合物作为廉价可循环利用的吸附剂,对阴离子类污染物显示了良好的吸附特性。从水滑石类化合物(HTLcs)的制备、对阴离子的吸附等方面简要介绍了目前国内外对HTLcs的研究进展。     

模拟菱锰矿硫酸浸出液中铁离子的去除

为了考察菱锰矿硫酸浸出液采用Na₃PO₄除铁的可行性,以及除铁所生成的FePO4滤渣用NaOH处理以回收PO₄^3-的效果,对Mn²⁺、Fe²⁺浓度分别为18.04、5.20 g/L的模拟菱锰矿硫酸浸出液进行了Na₃PO₄除铁、PO^3-₄回收工艺条件试验。结果表明：在H₂O₂用量为理论量、溶液pH=1.8、Na₃PO₄用量为1.7倍理论量、搅拌时间为15 min情况下,Fe²⁺去除率达99.85%、Mn2+损失率仅为2.23%;FePO4滤渣用0.75倍理论量的NaOH处理,反应3 h时的PO^3-₄回收率达98.24%。因此,菱锰矿硫酸浸出液采用Na₃PO₄除铁不仅可行,而且因PO3-4可回收再利用,除铁工艺成本较低。     

阴阳离子对离子膜电解性能的影响

通过离子膜污染物成分和二次盐水分析结果,提出了盐水中杂质对离子膜性能影响及建议。     

Identification of mNeonGreen as a pH-Dependent,Turn-On Fluorescent Protein Sensor for Chloride

Chloride-sensitive fluorescent proteins generated from laboratory evolution have a characteristic tyrosine residue that interacts with a chloride ion and π-stacks with the chromophore. However, the engineered yellow-green fluorescent protein mNeonGreen lacks this interaction but still binds chloride, as seen in a recently reported crystal structure. Based on its unique coordination sphere, we were curious if chloride could influence the optical properties of mNeonGreen. Here, we present the structure-guided identification and spectroscopic characterization of mNeonGreen as a turn-on fluorescent protein sensor for chloride. Our results show that chloride binding lowers the chromophore pK_a and shifts the equilibrium away from the weakly fluorescent phenol form to the highly fluorescent phenolate form, resulting in a pH-dependent, turn-on fluorescence response. Moreover, through mutagenesis, we link this sensing mechanism to a non-coordinating residue in the chloride binding pocket. This discovery sets the stage to further engineer mNeonGreen as a new fluorescent protein-based tool for imaging cellular chloride.     

Synthesis of Manganese Oxide Embedded Carbon Nanofibers as Effective Biomimetic Enzymes for Sensitive Detection of Superoxide Anions Released from Living Cells

Carbon nanofiber/manganese oxide (CNF‐MnO) hybrid nanofibers are synthesized by calcination of potassium permanganate (KMnO₄) loaded bacterial cellulose (BC) hydrogels. The chemical structure, morphology, performance, and application of CNF‐MnO aerogels are characterized and studied. The results revealed that MnO nanoparticles are uniformly deposited on the surface of CNF which derived from BC hydrogels. An amperometric superoxide anions (O₂^??) sensor is fabricated by the immobilization of the CNF‐MnO aerogels on a glassy carbon electrode, which displays a linear amperometric response with a high sensitivity of 76.2 µA cm^?2 × 10^?3m ^?1 and a low detection limit of 1.2 × 10^?9m in the concentration range of 5.0 × 10^?9m – 2.5 × 10^?6m . The successful detection of O₂^?? released from cancer cells verifies the potential application in biomedical field.     

A Highly Efficient and Stable Blue-Emitting Cs5Cu3Cl6I2 with a 1D Chain Structure

In the field of photonics, alkali copper(I) halides attract considerable attention as lead-free emitters. The intrinsic quantum confinement effects originating from low-dimensional electronic structure lead to high photoluminescence quantum yields (PLQYs). Among them, Cs₃Cu₂I₅ is the most promising candidate, satisfying both high PLQY and air stability. In this study, a strategy to explore a new material meeting these requirements through the use of the mixed-anions of I⁻ and Cl⁻ is proposed. The expectation is maintained that the large difference in ionic radii between them likely results in the formation of a novel compound. Consequently, Cs₅Cu₃Cl₆I₂ with a 1D zigzag chain structure is discovered. This material exhibits blue emission (≈462 nm) with a near-unity quantum yield of 95%. An electronic structure calculation reveals that the localized nature of the valence band maximum is crucial in obtaining efficient self-trapped exciton emission. Moreover, the iodine-bridged 1D connectivity significantly enhances the chemical stability of Cs₅Cu₃Cl₆I₂, compared with the pure chloride phase. The present findings provide a new perspective for developing air-stable alkali copper(I) halides with highly efficient luminescence.