甲亢病人血清镁含量及其临床意义

用火焰原子吸收法测定了２０００例甲亢病人的血清镁含量及１２００例天津市正常人群血清镁含量，结果显示，甲亢病人血清镁含量显著低于正常人群，有显著统计意义（Ｐ〈０．０１）。提示：甲亢病人血清镁含量对甲亢病诊断及治疗过程的镁的摄入补充有重要的意义。     

Atomic absorption spectrometric and potentiometric microdetermination of the nitro and nitroso groups in organic compounds

New simple, rapid, accurate, and selective methods are described for microdetermination of the nitro and nitroso groups in organic compounds. These are based on reduction with cadmium metal and 0.05 M HCl whereby 6 and 4 equivalents of the cadmium ions are released per nitro and nitroso groups, respectively. The cadmium ions are measured by atomic absorption spectrometry at 228.8 nm, potentiometrically by titration with EDTA using the cadmium ion selective electrode, and visually by EDTA titration using Eriochrome Black T indicator. Results with an average recovery of 98% and a mean standard deviation of 1.3% are obtainable and no interferences are caused by many nitrogen, oxygen, and sulfur functional groups.     

英平诸痹灵药酒中钴,锶,锂含量分析

采用火焰原子吸收分光光度法测定５种英平诸痹灵药酒中钴、锶、锂的含量。结果表明，该类药酒中微量元素Ｓｒ含量较高，微量元素Ｃｏ、Ｌｉ含量较低，该结果为讨论抗类风湿药物中微量元素与治疗类风湿疾病的关系提供了有用数据。     

健儿三宝冲剂治疗儿童钙,铁,锌缺乏症164例临床观察

用健儿三宝冲剂治疗的儿童钙，铁，锌缺乏症，经临床观察，取得了较好的疗效。     

Selective kinetic determination of pyridoxal-5'-phosphate with an ammonia gas-sensing electrode

The coenzyme pyridoxal-5'-phosphate (PLP) is deiermined by in situ measurement of the rate of ammonia production using a potentiometric gas-sensing membrane electrode. It is shown that the initial rate of ammonia liberation from L-tryptophan by action of tryptophanase apoenzyme and the coenzyme can be linearly related to PLP levels in the nanogram range with minimal interference from related compounds. Calibration data for the 1 × 10^-7–2.5 × 10^-6 M range for PLP yielded a least-squares equation of rate (mV min^-1) = (0.64 ± 0.01) C — 0.01 ± 0.02 with a standard error of 0.02 mV min^-1, where concentration, C, is expressed in units of 10^-7 mol l^-1.     

慢性胃炎、溃疡病患者血清、胃液和胃组织微量元素的测定及其临床意义

对慢性胃炎、溃疡病患者血清、胃液、胃组织中多种微量元素采用高频等离子体发射光谱法测定．结果：胃溃疡血清、胃组织钼低，Ｐ均＜０．０５；胃组织钙低，Ｐ＜０．０１．十二指肠溃疡血清、胃组织钼低，Ｐ均＜０．０５；胃组织钙高于对照组，Ｐ＜０．０１．并对健康人血清、胃液、胃组织微量元素进行测定，为科研提供了血清、胃液、胃组织微量元素的正常值。     

Probing the intrinsic electronic structure of the cubane [4Fe-4S] cluster: nature's favorite cluster for electron transfer and storage

The cubane [4Fe-4S] is the most common multinuclear metal center in nature for electron transfer and storage. Using electrospray, we produced a series of gaseous doubly charged cubane-type complexes, [Fe4S4L4]2- (L = -SC2H5, -SH, -Cl, -Br, -I) and the Se-analogues [Fe4Se4L4]2- (L = -SC2H5, -Cl), and probed their electronic structures with photoelectron spectroscopy and density functional calculations. The photoelectron spectral features are similar among all the seven species investigated, revealing a weak threshold feature due to the minority spins on the Fe centers and confirming the low-spin two-layer model for the [4Fe-4S](2+) core and its "inverted level scheme". The measured adiabatic detachment energies, which are sensitive to the terminal ligand substitution, provide the intrinsic oxidation potentials of the [Fe4S4L4]2- complexes. The calculations revealed a simple correlation between the electron donor property of the terminal thiolate as well as the bridging sulfide with the variation of the intrinsic redox potentials. Our data provide intrinsic electronic structure information of the [4Fe-4S] cluster and the molecular basis for understanding the protein and solvent effects on the redox properties of the [4Fe-4S] active sites.     

Gas–liquid partition coefficients and Henry's law constants of methyl mercaptan in aqueous solutions of Fe(II)–CDTA chelate complex

Utilization of ferric chelate complex of trans-1,2-cyclohexanediaminetetraacetic acid (CDTA) for the oxidative scrubbing of H₂S and CH₃SH in Kraft mill streams can be beneficial from the standpoints of iron protection against precipitation and oxygen-mediated regenerative oxidation of the ferrous chelate CDTA. The physical solubility of methyl mercaptan in CDTA–Fe(III) complex cannot be measured directly because of oxidation of the sulfur-bearing gaseous species with the ferric chelate. Therefore, this investigation was carried out to determine the gas–liquid partition coefficients and Henry's law constants of methyl mercaptan in aqueous iron-free CDTA solutions and non-reacting ferrous chelate solutions (CDTA–Fe(II) complex), using the static headspace method with an estimated accuracy of about 2%. Experiments with aqueous solutions of chelate concentrations varying between 38 and 300 mol m⁻³ were carried out at temperatures between 298 and 333 K and atmospheric pressure. It was shown that the methyl mercaptan solubility decreases with increasing temperature for all systems but was not much influenced, in the studied conditions, by the chelate concentration especially at larger temperatures.     

Microdetermination of chlorine and bromine in some organic compounds by ion-selective electrodes

Summary The solid state ion-selective chloride and bromide electrodes are used for the microdetermination of chlorine and bromine in organic compounds. After combustion in an oxygen-filled flask, potentiometric titration with silver nitrate at pH 5–7 in presence of 50% dioxan is carried out. Results accurate to ±0.3% absolute are obtained with some partially and highly halogenated compounds.

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Mikrobestimmung von Chlor und Brom in einigen organischen Verbindungen mit Hilfe von ionenselektiven Elektroden

Zusammenfassung Chlorid- und bromidselektive Festkörperelektroden wurden zur Chlor- und Brombestimmung in teilweise bzw. hochhalogenierten organischen Verbindungen benutzt. Nach Verbrennung im Sauerstoffkolben erfolgt eine potentiometrische Titration mit Silbernitrat bei pH 5–7 in Gegenwart von 50% Dioxan. Die erhaltenen Ergebnisse sind auf ±0,3 % genau.

     

Determination of calcium in silicate rocks by potentiometric titration with ethyleneglycol-bis-(2-Aminoethylether)tetraacetic acid and a calcium-selective electrode

The method reported for the determination of calcium in silicate rocks involves titration with ethyleneglycol-bis(2-aminoethylether)tetraacetic acid (EGTA) to a potentiometric end-point. A Crytur calcium-selective electrode is used; the selectivity constants (K_ca,x) are less than 10^-3 for Mg, Ba, Sr, K and Na. The method can be used for calcium contents of 2% or higher (and exceptionally for lower contents), in the presence of up to 60% Mg, 33% AI, 17% Fe, 5% Ba, 5% Ti, and 2.5% Mn. Al, Fe and Ti are masked with sulphosalicylic acid, barium is precipitated as its sulphate, and manganese is bound as its cyanide complex. If the magnesium content is less than that of calcium, EDTA can be used as titrant, magnesium being masked with acetylacetone.