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101.
Using synthetic substrates, an uncomplicated and sensitive procedure for the identification and determination of extracellular
aminopeptidase was developed. The β-naphthylamides of the amino acids were applied for the identification of extracellular
aminopeptidase, whereas the 4-(phenylazo) phenylamides of the amino acids were used for the determination of intra-and extracellular
aminopeptidase activity. The results show a 81.8–88.9% intracellular and 11.1–18.2% extracellular distribution of the studied
enzyme activity.
Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 167–169, March–April, 2007. 相似文献
102.
纳米CoHCF修饰电极的制备及其对血红蛋白的电化学测定研究 总被引:1,自引:0,他引:1
A cobalt hexacyanoferrate (CoHCF) nanoparticle (size ca. 60 nm) chemically modified electrode (CME) was fabricated and the electrochemical behavior of hemoglobin (Hb) at this nanosized CoHCF CME was studied. In comparison with a bare glassy carbon electrode (GCE) and a general CoHCF CME electrodeposited in a traditional manner, the present nanosized CoHCF CME performed efficiently electrocatalytic reduction for Hb with relatively high sensitivity, stability, and longlife, Combined with liquid chromatography (LC), the nanosized CoHCF CME was used as the electrochemical detector of Hb in the established flow injection analysis-electrochemical determination (FIA-ECD) system. The peak current was a linear function of concentrations in the range from 2.5×10^-8 to 5.0×10^-6mol/L for Hb, with detection limit of 1.4×10^-8 mol/L. The FIA-ECD system has been successfully applied to assess the Hb content of clinic blood samples with advantages of sensitiveness, speediness, easy control and small sample-consumption. 相似文献
103.
de Toledo RA Santos MC Cavalheiro ET Mazo LH 《Analytical and bioanalytical chemistry》2005,381(6):1161-1166
This work describes an electroanalytical investigation of dopamine using cyclic voltammetry (CV) and the graphite–polyurethane composite electrode (GPU). In CV studies, well-defined redox peaks characterize the oxidation process at the GPU electrode, which is indicative of electrocatalytic effects associated with active sites on the GPU electrode surface. A new analytical methodology was developed using the GPU electrode and square wave voltammetry (SWV) in BR buffer solution (0.1 mol L–1; pH 7.4). Analytical curves were constructed under optimized conditions (f=60s–1, Ea=50 mV, EI=2 mV) and detection and quantification limits of 6.4×10–8 mol L–1 (12.1 g L–1) and 5.2×10–6 mol L–1 (0.9 mg L–1), respectively, were achieved. The precision of the method was checked by performing ten successive measurements for a 9.9×10–6 mol L–1 dopamine solution. For intra-assay and inter-assay precisions, the relative standard deviations were 1.9 and 2.3%, respectively. In order to evaluate the developed methodology, the determination of dopamine was performed with good sensitivity and selectivity, without the interference of ascorbic acid in synthetic cerebrospinal fluid, which indicates that the new methodology enables reliable analysis of dopamine. 相似文献
104.
A sensitive ion-pair liquid-liquid extraction-spectrophotometric method has been developed for the determination of copper, palladium, iron and cobalt, based on the formation of metal complexes with 1-nitroso-2-naphthol-6-sulphonic acid or 2-nitroso-1-naphthol-6-sulphonic acid as primary ligand, and zephiramine as counter-ion. The coloured metal complexes obtained over different pH ranges are easily and quantitatively extracted into dichloromethane. The method has been tested with samples containing known amounts of copper, palladium, iron and cobalt in ultrapure water. The reagents provide a sensitive spectrophotometric method for determining these metals. 相似文献
105.
Hydrogen peroxide in basic media is proposed as a means for dissolving whole blood samples to be analyzed by electrothermal atomization atomic absorption spectrometry, ET AAS. Approximately 2 g of the whole blood sample were directly weighed in a 150 mL volumetric flask; 3 mL of a NaOH 0.2 mol L−1 solution, two drops of 1-octanol, as an antifoaming agent, and 1 mL of 30% volume hydrogen peroxide were added to the flask to promote oxidation. The solution was then manually shaken and after approximately three minutes of shaking, a clear solution, with no apparent suspended solids or greasy layers, was obtained. Distilled-deionized water was used to complete the volume. Ten μL of the resulting solution along with 10 μL of a solution containing 5000 mg L−1 of NH4H2PO4 and 300 mg L−1 of Mg(NO3)2 as a modifier, were injected into transversely heated graphite tubes for lead determination. Both aqueous standards and standard addition calibration curves produced results not significantly different at a 95% confidence limit level. Accuracy of the measurements was assessed by analysis of the IAEA A-13 (concentration of trace and minor elements in freeze dried animal blood) standard reference material containing 0.18 mg L−1 lead on a dry basis and by means of recovery tests. Analysis of the IAEA A-13 standard produced 0.17 ± 0.02 mg L−1 lead on a dry basis; recovery tests afforded values from 95 to 105%. Ten consecutive measurements of a 5 ppb lead solution gave a characteristic mass of 47.2 pg and a (3S) detection limit of 1.77 μg L−1 Pb. Results obtained from analysis of whole blood samples of volunteer donors covered a lead concentration range between 8 and 21 μg L−1 with a mean value of 11.9 ± 4.7 μg L−1. 相似文献
106.
陶俊 《理化检验(化学分册)》2007,43(4):311-312
报道了硅铁中锰、钙、铝、铬及铜五元素的电感耦合等离子原子发射光谱法(ICP-AES)同时测定方法.对仪器的工作条件和各元素分析谱线的选择进行了试验和优化.通过对多个硅铁标准样品的分析,证实了方法的可行性,所得测定结果与标准值一致.回收率试验所得结果在99.0%~105.0%之间. 相似文献
107.
108.
二氧化碳和氧气的快速电化学方法联合测定 总被引:4,自引:0,他引:4
根据O2和CO2在二甲亚砜(DMSO)介质中Pt电极上的伏安特性,采用微电极并结构计算机控制的电位调制技术,建立了快速联合测定CO2和O2的调制电位脉冲库仑法和调制电位脉冲电流法,取得了满意的结果。一次测量时间快达40ms。CO2检测范围0 ̄10%(体积百分比);O2检测范围不受限制。通过编程设计特定的调制电位-时间波形,可保持连续检测的长期稳定性。 相似文献
109.
Guido Kickelbick Dieter Rutzinger Thomas Gallauner 《Monatshefte für Chemie / Chemical Monthly》2002,133(8):1157-1164
Summary. Hexadentate ligands were formed by the reaction of primary dimethylaminoethyl- or methoxyethylamines with formaldehyde. The
resulting N, N′, N″-functionalized hexahydro-1,3,5-triazines contain pending amino or ether functionalities which are able to coordinate to
metals in addition to the ring nitrogen atoms. Both ligands were reacted with CuBr, and novel tricopper clusters were isolated
and characterized by X-ray structure analysis. In these compounds a ring nitrogen atom, the pending amino or ether functionality,
and two bridging bromine atoms coordinate each of the copper atoms.
Received January 22, 2002; accepted (revised) March 22, 2002 相似文献
110.