Biparametric potentiometric analytical microsystem for nitrate and potassium monitoring in water recycling processes for manned space missions

The construction and evaluation of a Low Temperature Co-fired Ceramics (LTCC)-based continuous flow potentiometric microanalyzer prototype to simultaneously monitor the presence of two ions (potassium and nitrate) in samples from the water recycling process for future manned space missions is presented. The microsystem integrates microfluidics and the detection system in a single substrate and it is smaller than a credit card. The detection system is based on two ion-selective electrodes (ISEs), which are built using all-solid state nitrate and potassium polymeric membranes, and a screen-printed Ag/AgCl reference electrode. The obtained analytical features after the optimization of the microfluidic design and hydrodynamics are a linear range from 10 to 1000 mg L⁻¹ and from 1.9 to 155 mg L⁻¹ and a detection limit of 9.56 mg L⁻¹ and 0.81 mg L⁻¹ for nitrate and potassium ions respectively.     

高铁酸钾的合成与电化学性能研究

本文主要研究了锂离子电池正极材料高铁酸钾的合成,表征和电化学性质.用次氯酸钾与硝酸铁于碱性介质中反应得到高铁酸钾粗品,重结晶后成纯度大于97%的产品,用XRD和FTIR等方法对高铁酸钾进行表征和分析.初步研究了K2FeO4/Li电池的充放电性能.     

单扫描示波极谱法测定扑热息痛

扑热息痛与NaNO2在中性介质中发生反应，其亚硝化衍生物具有良好的电活性。在pH9．37的Britton-Robinson缓冲溶液中，于-0．56V(vs．SCE)产生灵敏的极谱还原峰，峰电流与扑热息痛质量浓度在0．007-0．4mg/L范围有良好的线性关系，检测下限为5μg/L。此法已用于测定小儿速效感冒灵。     

多巴酚丁胺的流动注射化学发光法测定

在盐酸介质中 ,高锰酸钾可氧化多巴酚丁胺产生化学发光 ,甲醛对该反应有较强的增敏作用 ,据此 ,建立了流动注射化学发光法测定多巴酚丁胺的方法 ;方法的线性范围为0.1～100mg·L -1,检出限为0.07mg·L -1 ,相对标准偏差为1.2 %(n=11,ρ=1.0mg·L -1) ;该法用于药物中多巴酚丁胺含量的测定 ,结果令人满意。     

Markovnikov addition of vinyl acetate with azoles catalyzed by potassium tert-butoxide

A simple and efficient methodology for Markovnikov addition of azoles with vinyl acetate catalyzed by potassium tert-butoxide is described.N-heterocyclic compounds are synthesized from simple and commercially available starting materials under mild conditions in high yields.     

Flow injection analysis of potassium using an all-solid-state potassium-selective electrode as a detector

The concentration of potassium was determined by a combination of flow injection analysis (FIA) with an all-solid-state potassium sensor detection. The all-solid-state potassium-selective electrode possessing long-term potential stability was fabricated by coating an electroactive polypyrrole/poly(4-styrenesulfonate) film electrode with a plasticized poly(vinyl chloride) membrane containing valinomycin. The simple FIA system developed in this laboratory demonstrated sensitivity identical to that in the batch system and achieved considerably rapid assay (150 samples h⁻¹). Analyses of soy sauce and control serum samples by this FIA system yielded results in good agreement with those obtained by conventional measurements.     

Synthesis and Characterization of Methylzinc Tri(tert‐butyl)silylphosphanide as well as Related Sodium and Potassium Phosphanylzincates

The reaction of dimethylzinc and tri(tert‐butyl)silylphosphane in toluene yielded dimeric methylzinc tri(tert‐butyl)silylphosphanide ( 1 ) which crystallized tetrameric. Compound 1 was deprotonated with sodium in DME and the solvent‐separated dimeric ion pair [(dme)₃Na]⁺ [(dme)Na(MeZn)₂(μ‐PSitBu₃)₂]^? ( 2 ) was isolated. The reaction of 1 in THF with two equivalents of potassium and one equivalent of tri(tert‐butyl)silylphosphane gave dimeric [{tBu₃Si(H)P}{(thf)₂K}₂(MeZn)(PSitBu₃)]₂ ( 3 ). Both of these phosphanylzincates contain Zn₂P₂ cycles with Zn‐P bond lengths of approximately 237 pm, whereas in 1 larger Zn‐P bond lengths of 248.5 pm were found due to the larger coordination numbers of the phosphorus and zinc atoms.     

Study on the initiation step of vinyloxirane and 3-butenyloxirane polymerization by alkalide K, K(15-crown-5)2

Transfer of one electron from potassium anion of alkalide K⁻, K⁺(15-crown-5)₂ to the double bond of vinyloxirane results in the oxirane ring opening exclusively in the α-position. K⁰ and radical anions are formed in the process. The former transfers the second electron mainly to the next monomer molecule. The latter dimerize to potassium glycoxides, which initiate the polymerization of vinyloxirane. The introduction of two CH₂ groups between the double bond and the oxirane ring changes the way of electron transfer. The oxirane ring of 3-butenyloxirane becomes the electron acceptor and its opening occurs in the β-position. In this case K⁰ transfers the second electron to the primarily formed radical anion giving an organopotassium intermediate. It reacts with crown ether. Potassium alkoxides are the reaction products. They become the real initiators of 3-butenyloxirane polymerization.     

Electron-transfer reduction of selected alcohols with alkalide K, K(15-crown-5)2 via organometallic intermediates

The course of the reaction of alkalide K⁻, K⁺(15-crown-5)₂1 with selected alcohols depends on the kind of alcohol and the mode of substrate delivery. In the case of methanol, potassium methoxide formed initially undergoes destruction at the excess of 1. It results in potassium oxide and methylpotassium. The latter opens the crown ether ring giving potassium tetraethylene glycoxide vinyl ether and methane. A similar course of the process is observed for propanol. Potassium glycidoxide is the main product formed in the reaction of 1 with glycidol. Its oxirane ring is opened at the excess of 1. Organopotassium alkoxides, i.e., potassium potassiomethoxide and dipotassium potassiopropane-1,2-dioxide are intermediate products of this reaction. They react then with the crown ether. Potassium methoxide, potassium enolate of acetaldehyde, dipotassium propane-1,2-dioxide and potassium tetraethylene glycoxide vinyl ether are the final products of this process.     

Improving palladium-catalyzed cyanation of aryl halides: development of a state-of-the-art methodology using potassium hexacyanoferrate(II) as cyanating agent

Benzonitriles are easily accessible via palladium-catalyzed cyanation of aryl halides using potassium hexacyanoferrate(II) as cyanide source. This method is applicable on both activated and deactivated aryl and heteroaryl bromides and activated chlorides giving the corresponding benzonitriles in good to excellent yield. Advantageously, the used cyanating agent is non-toxic and cheap. The presented catalyst system is rather simple and it is not necessary to add expensive phosphines, making the novel method also attractive for industrial applications.