金属离子增稳的酶法终点法测定1,5-脱水葡糖醇

为建立金属离子增稳的酶法终点法测定1,5-脱水葡糖醇,通过葡萄糖激酶(GK)和葡萄糖-6-磷酸脱氢酶(G6PD)将样品中葡萄糖(Glu)转化为6-磷酸葡萄糖内酯(G6PL),1,5-AG经吡喃糖氧化酶(PROD)作用生成1,5-脱水果糖(1,5-AF)和H2O2,后者借Trinder’s系统显色定量。结果表明,该法线性范围0～250μmol/L,平均回收率为99.3%,批内变异系数(CV)和批间变异系数分别为0.009 8～0.027 7、0.016 2～0.036 8,与气相色谱-质谱法(GC-MS)比较具有良好的相关性,线性回归方程和相关系数分别为y=0.982 x+2.68,r=0.998 8。以金属离子为增稳剂的酶法终点法测定1,5-AG含量具有简便、灵敏、可靠的特点,适合实际推广应用。     

Simultaneous determination of glucose, 1,5-anhydro-d-glucitol and related sugar alcohols in serum by high-performance liquid chromatography with benzoic acid derivatization

A new, simple and sensitive pre-column high-performance chromatographic method for the determination of diabetes marker d-glucose, 1,5-anhydro-d-glucitol and related compounds is reported. Sugars (d-glucose, d-galactose, d-mannose, sucrose and arabinose) were derivatized with benzoic acid (BA) at 80 degrees C for 60 min. l-Fucose, fructose, d-lactose, l-rhamnose, arabinose and ascorbic acid were not reacted. Sugar alcohols (xylitol, erythritol, mannitol, sorbitol myo-inositol) were also derivatized with BA at 80 degrees C for 60 min. The fluorescence derivatives were separated on a TSK amide 80 column (4.6 mm i.d. x 250 mm, 5 microm) with acetonitrile-50 mm acetate buffer (pH 5.6; 4:96, v/v) as the mobile phase. The detection wavelength of beizoic acid derivatives was lambda(ex) 275 nm and lambda(em) 315 nm. The detection limits of sugars were 10-80 microg/mL. The calibration graphs were linear up to 10 mg/mL. The relative standard deviations of 500 microg/mL sugars were 7.0-7.3%. The proposed method was compared with the enzymatic photometric glucose analysis method (Glucose B-Test II Wako). The correlation coefficient was 0.83 (n = 20) and y = 0.82x + 5.91, where y and x are concentrations in microg/mL obtained by the proposed pre-column HPLC and enzyme-photometric method, respectively. The detection limits of sugar alcohols were 100-1000 ng/mL. The calibration graphs were linear to 50 microg/mL and relative standard deviations of 10 microg/mL were 7.2-8.2%. The 1,5-AG data by the proposed method was also compared with the enzymatic photometric 1,5-AG analysis method (Rana AG 1,5-AG determination kit, Nihon Kayaku) and good correlation (r = 0.91, n = 20) was also obtained. The proposed method was applied to the simultaneous determination of d-glucose, 1,5-AG and related sugar alcohols in serum from healthy males.     

托吡卡胺对映体的毛细管电泳-方波安培分离检测

采用毛细管电泳-方波安培检测法,在熔融石英毛细管(75 μm i.d.×50 cm)中,以7 mmol/L 三羟甲基氨基甲烷(Tris)-10 mmol/L柠檬酸-2 mmol/L硼酸-15mmol/L β-环糊精 （β-CD） (pH 3.0)为电泳介质,采用重力进样,高度差为20 cm,进样时间为10 s,在分离电压为15 kV,方波平衡电位+0.8 V的条件下,实现了托吡卡胺对映体的分离检测。线性范围为5~750 μmol/L,检出限为2 μmol/L。对影响分离度的因素β-CD浓度、硼酸浓度及p     

New whole blood methods and instruments: glucose measurement and test menus for critical care.

A glucose oxidase-H 2O 2 substrate-selective electrode (SSE) along with eight other electrodes allows the Stat Profile 5 (SP5) to measure glucose, electrolytes, blood gases, pH, and hematocrit simultaneously in whole blood. For heparinized blood gas syringe samples (n=178), orthogonal (Deming) regression showed y=0.43 + 1.00x (mmol/L), where y is whole blood glucose, and x is plasma glucose measured with the Ektachem 400 glucose oxidase slide method. For heparinized plasma (n=197), y=0.25 + 1.02x. Least squares linear regression showed y=0.25 + 1.00x (s yxx=0.49) for whole blood versus plasma, y = 0.30 + 1.01x (s yxx=0.49) for plasma versus plasma, and r=0.994 for both cases. Whole blood and plasma glucose in the same samples measured by SSE differed by less than 1%. The SP5 combines the largest number of whole blood tests currently available in a rapid response instrument well-suited for care of the critically ill patient.     

l-Glutamate biosensor for estimation of the taste of tomato specimens

An amperometric biosensor has been developed for measurement of Umami, or the taste based on the amount of L-glutamate, in tomato foods. The biosensor is based on an enzyme-mediator system in which L-glutamate oxidase is used for biochemical oxidation of L-glutamate and a tetrafulvalene-tetracyanoquinodimethane (TTF-TCNQ) paste, prepared from the mixture of TTF-TCNQ salt, graphite powder, and silicone oil, serves as the mediator. The limit of detection, calculated by use of a four-parameter logistic model, was 0.05 mmol L(-1), and the limit of quantification was 0.15 mmol L(-1). The correlation coefficient (R2) was 0.990 and the relative standard deviation was no more than 1% (n=5). The response time (tau (95)) was 20-50 s, depending on concentration. The repeatability of the sensor was better than 5% (n=10). The sensor developed was stable for more than ten days.     

Ion chromatographic determination of hydroxide ion on monolithic reversed-phase silica gel columns coated with nonionic and cationic surfactants

The determination of hydroxide by ion chromatography (IC) is demonstrated using a monolithic octadecylsilyl (ODS)-silica gel column coated first with a nonionic surfactant (polyoxyethylene (POE)) and then with a cationic surfactant (cetyltrimethylammonium bromide (CTAB)). This stationary phase, when used in conjunction with a 10 mmol/l sodium sulfate eluent at pH 8.2, was found to be suitable for the rapid and efficient separation of hydroxide from some other anions, based on a conventional ion-exchange mechanism. The peak directions and detection responses for these ions were in agreement with their known limiting equivalent ionic conductance values. Under these conditions, a linear calibration plot was obtained for hydroxide ion over the range 16 micromol/l to 15 mmol/l, and the detection limit determined at a signal-to-noise ratio of 3 was 6.4 micromol/l. The double-coated stationary phase described above was shown to be superior to a single coating of cetyltrimethylammonium bromide alone, in terms of separation efficiency and stability of the stationary phase. A range of samples comprising solutions of some strong and weak bases was analyzed by the proposed method and the results obtained were in good agreement with those obtained by conventional potentiometric pH measurement.     

Analysis of anthraquinones in Rumex crispus by micellar electrokinetic chromatography

A micellar electrochromatographic method was performed for the analysis of the pharmaceutically important anthraquinones from the root of Rumex crispus. The separation of 1,5-dihydroxy-3-methylanthraquinone (1); 1,3,5-trihydroxy-6-hydroxymethylanthraquinone (2); 1,5-dihydroxy-3-methoxy-7-methylanthraquinone (3) was achieved in 6 min using a running buffer containing 10 mmol/l sodium borate, 50 mmol/l sodium dodecylsulfate, and 25% acetonitrile at pH 10.6. The method is simple, rapid, and reproducible.     

Enzyme electrochemical preparation of a 3-keto derivative of 1,5-anhydro-d-glucitol using glucose-3-dehydrogenase

A novel enzymatic organic synthesis was reported, utilizing glucose-3-dehydrogenase (G3DH) and its regeneration via electrochemical methods. We combined the water-soluble G3DH prepared from a marine bacterium, Halomonas sp. α-15, and electron mediator with the electrode system in order to regenerate the enzyme. Using this system, the conversion of 1,5-anhydro-d-glucitol (1,5AG), a diabetes marker in human blood, was investigated. The final yield of the product, 3-keto anhydroglucitol (3-ketoAG), which was identified by ¹³C nuclear magnetic resonance, was 82% based on the initial amount of 1,5AG. The electrochemical yield of the reaction proceeded almost stoichiometrically. The electrochemical conversion rate of 1,5AG was 1.24 mmol/(L·h), and the electrochemical yield of 1,5AG consumption was 80%, whereas that for 3-ketoAG was 60%.     

二硫苏糖醇直接光度法测定钴离子含量

为建立简便、灵敏测定钴离子含量的方法,在表面活性剂存在下,用二硫苏糖醇(DTT)为显色剂测定钴离子.结果表明,该法线性范围0～6.00 mmol/L,平均回收率为99.4%,批内变异系数(CV)和批间变异系数分别为0.022、0.038,与原子吸收法比较具有良好的相关性,线性回归方程和相关系数分别为y =0.997 6...     

Co<Superscript>II</Superscript> and Rh<Superscript>I</Superscript> complexes with <Emphasis Type="Italic">C</Emphasis><Subscript>2</Subscript>-symmetric chiral diamines of the dioxolane series

The reaction of di-μ-chlorobis(1,5-cyclooctadiene)dirhodium with (4S, 5S)-2,2-dimethyl-4,5-bis(methylaminomethyl)-1,3-dioxolane (1) gave the complex [Rh(cod)(1)]Cl (cod is 1,5-cyclooctadiene). The composition of the complexes CoCl₂ · L₂ and [Rh(cod)(L₂)]X (L₂ = 1, (4S,5S)-2,2-dimethyl-4,5-bis(aminomethyl)-1,3-dioxolane, and (4S, 5S)-2,2-dimethyl-4,5-bis(dimethylaminomethyl)-1,3-dioxolane; X = Cl, TfO) was studied using IR and ¹H NMR spectroscopy. In the Rh^I cyclooctadienediamine complexes, the diene molecule forms a stronger bond with the metal atom than that in the cyclooctadienediphosphine analogs. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2270–2274, October, 2005.     

高效液相色谱法测定尿液中的异硫氰酸酯

 省去合成1,3 苯二硫杂环五烯 2 硫酮这一步骤，直接用异硫氰酸丙基酯与1,2 苯二硫酚反应作标准，建立了尿液中异硫氰酸酯的反相高效液相色谱(HPLC)测定方法。异硫氰酸丙基酯的标准曲线回归方程 y =0.418 2x + 2.821 ( r2 = 0.999 3 )与异硫氰酸甲基酯的回归方程 y = 0.412 2x + 2.442 3 ( r 2= 0.996 6 )基本拟合。检出限(以信噪比为2.5计)为0.08 μ mol/L 。日内重现性( n =21)以相对标准偏差(RSD)表     

Electrochemiluminescent determination of L-cysteine with a flow-injection analysis system.

A flow-injection electrochemiluminescent method for L-cysteine determination has been developed based on its enhancement of the electrochemiluminecence of luminol at a glassy carbon electrode. This method is simple and sensitive for cysteine determination. Under the selected experimental parameters, the linear range for cysteine concentration was 1.0 x 10(-6) - 5.0 x 10(-5) mol/l, and the detection limit was 0.67 micromol/l (S/N = 3). The relative standard deviation for 11 measurements of 1.0 x 10(-5) mol/l cysteine was 4.5%. The proposed method has been applied to the detection of cysteine in pharmaceutical injections with satisfactory results.     

亲和毛细管电泳法测定牛血清白蛋白和加替沙星的结合常数

利用亲和毛细管电泳法对牛血清白蛋白(BSA)与加替沙星(GT)间的结合反应及其相互作用做了初步探索,并应用淌度比(M)作为指标测定了两者的结合常数。以20 mmol/L pH 7.4的磷酸盐缓冲液作为运行缓冲液,分别以GT和BSA作为添加剂,另一组分为进样样品,内标为二甲基甲酰胺,于214 nm波长下检测。两种测定条件下得到的结合常数分别为4.4×104 L/mol和4.2×104 L/mol,与传统的荧光淬灭法测得的结果基本一致。该方法具有简单、高效的优点。     

Development of a novel fluorescent probe for nitric oxide detection: 8-(3',4'-diaminophenyl)-difluoroboradiaza-S-indacence

A novel fluorescent probe, 8-(3',4'-diaminophenyl)-difluoroboradiaza-S-indacence (DABODIPY), was designed and synthesized for monitoring nitric oxide production, which features high photostability and no pH dependency over a wide pH range. The fluorescence of 8-(3',4'-diaminophenyl)-difluoroboradiaza-S-indacence is very low, however, when the probe traps nitric oxide (NO) in the presence of dioxygen, the strong fluorescent triazole form is obtained, which offers the advantages of specificity, and sensitivity for direct detection of NO. Calibration using various concentrations of NO showed the method has good linearity (0.08-4.00 micromol l(-1)) and its detection limit is 10 nmol l(-1) (s/n = 3). The proposed method has been used to monitor the release of NO from S-nitrosocysteine, a NO-releasing agent.     

Flow injection spectrophotometric determination of reducing sugars using a focalized coiled reactor in a domestic microwave oven

A flow injection (FI) spectrophotometric procedure for determining reducing sugars content in sugar cane juices using a focalized PTFE coiled reactor positioned at the output antenna of a domestic microwave oven at 700 W is proposed. In this system, sample solution converge to 1.0 mol l(-1) NaOH and 5.2 mmol l(-1) K(3)Fe(CN)(6) solutions previously mixed and the decrease of hexacyanoferrate(III) concentration was monitored at 420 nm. Under best analytical conditions, there was a direct relationship between absorbance decrease and reducing sugar content (fructose plus glucose concentrations) in the concentration range from 50 to 1200 micromol l(-1) with a detection limit of 15 micromol l(-1). The relative standard deviations (rds) were less than 1.4% for ten injection of 400 and 800 micromol l(-1) fructose solution and the analytical frequency was 70 h(-1). A paired t-test showed that all results obtained for sugar cane juices using this FI procedure and the Somogyi-Nelson batch procedure agree at the 95% confidence level.     

Plant tissue-based chemiluminescence biosensor for ethanol.

A plant tissue-based chemiluminescence biosensor for ethanol based on using mushroom (Agaricus bisporus) tissue as the recognition element is proposed in this paper. The principle for ethanol sensing relies on the luminol-potassium hexacyanoferrate(III)-hydrogen peroxide transducer reaction, in which hydrogen peroxide is produced from the ethanol enzymatic catalytic oxidation by oxygen under the catalysis of alcohol oxidase in the tissue column. Under optimum conditions, the method allowed the measurement of ethanol in the range of 0.001 - 2 mmol/l with a detection limit (3 sigma) of 0.2 micromol/l. The relative standard deviation (RSD) was 4.14% (n = 11) for 0.05 mmol/l ethanol. The proposed method has been applied to the determination of ethanol in biological fluids and beverages with satisfactory results.     

Preparation of nanoparticle colloids of methoxy poly(ethylene glycol)-<Emphasis Type="Italic">b</Emphasis>-poly(<Emphasis Type="SmallCaps">D</Emphasis>,<Emphasis Type="SmallCaps">L</Emphasis>-lactide): effects of surfactant and organic solvent

Nanoparticle colloids of methoxy poly(ethylene glycol)-b-poly(D,L-lactide) (MPEG-b-PDLL) diblock copolymer were prepared by a modified spontaneous emulsification solvent diffusion method using acetone/ethanol as the mixture organic solvents. The MPEG-b-PDLL was synthesized by ring-opening polymerization of D,L-lactide using stannous octoate and MPEG with molecular weight of 5,000 g/mol as the initiating system. The MPEG-b-PDLL obtained was an amorphous polymer with molecular weight of 73,600 g/mol. Influences of acetone/ethanol (v/v) ratios and Tween 80 surfactant concentrations on characteristics of the colloidal nanoparticles were investigated and discussed. Light-scattering analysis showed that average diameters of the surfactant-free colloidal nanoparticles were in the range of 86–124 nm. The nanoparticle sizes decreased as the ethanol ratio increased. The Tween 80 did not show the significant effect on the nanoparticle sizes. Scanning electron micrographs of dried nanoparticles that demonstrated the aggregation of most particles suggested they were the soft nanoparticles. However, the dried nanoparticle morphology can be observed from scanning electron microscopy as having a spherical shape and smooth surfaces.     

双功能催化剂Nix/MgyAl2O y+3用于丁酮烷基化反应

以Nix/zMgy/zAl2/z(OH)2(CO3)1/z(z=x+y+2,x=0.2、1,5≤y≤11.8)水滑石为前驱体,经高温焙烧和H2还原后得到了一系列可用于甲醇-丁酮(MEK)烷基化反应的Nix/MgyAl2Oy+3(x=0.2、1,5≤y≤11.8)双功能催化剂,并采用X射线衍射(XRD)、透射电子显微镜(TEM)、程序升温还原(TPR)、程序升温脱附(TPD)等技术对催化剂的结构和形貌进行了表征。活性实验结果发现Ni/Mg9Al2O12催化剂具有较好的活性,在常压、温度280℃、原料液时空速(LHSV)6.0 h-1的条件下,丁酮的转化率为61.6%,3?戊酮(DEK)和3?甲基?2?丁酮(MIPK)的选择性分别为45.0%和17.7%。表征结果表明催化剂中合适的活性金属Ni和MgO含量对提高DEK和MIPK的选择性具有重要的影响,Ni与催化剂表面碱量之间的协同作用可能是影响催化剂的活性和选择性的主要因素。     

空心纳米金在甲醛气体传感器中的应用研究

通过牺牲模板法合成了具有空心结构的纳米金催化剂,并进行了TEM、 SEM和XRD等物理表征.把该催化剂作为工作电极的活性物质,以1 mol/L KOH为电解质,组装了电流型甲醛气体传感器.在甲醛气体浓度为0～2.23×10-6 mol/L范围内对传感器进行了性能测试,传感器响应信号y(A)与气体浓度x(mol/L)线性回归方程为y=16.63x+4.063×10-7, r=0.9989.该传感器灵敏度高于同载量实心金纳米催化剂组装的传感器70%左右,达到了降低贵金属用量的目的.因其具有较快的响应时间、 良好的重现性和良好的线性关系等优点,可用于适当浓度范围内的甲醛气体检测.     

Cobalt determination with FI-FAAS after on-line sorbent preconcentration using 1-nitroso-2-naphthol

The suitability of 1-nitroso-2-naphthol (NN) as a complexing agent for on-line preconcentration of cobalt using C(18) microcolumn with FI-FAAS system has been tested. Various parameters affecting the complex formation and its elution were optimized. Reagent solution (2.5x10(-3) mol l(-1)) and aqueous sample solution acidified with 0.1% (v/v) nitric acid were on-line mixed in a reaction coil set at 65+/-1 degrees C and flowed through the microcolumn for 30 s. The pH of the mixed solution was adjusted to 3 approximately 4 by adding HNO(3) (1 mol l(-1)) or NaOH (1 mol l(-1)) in the reagent solution. The adsorbed complexes in the microcolumn were eluted with ethanol (acidified to 1% nitric acid) in 10 s into the nebulizer of FAAS. A good precision (1.6% for 100 mug l(-1) Co(II), n=10), high enrichment factor 17.2, with detection limit (3sigma) 3.2 mug l(-1), and sample throughput (90 h(-1)) were obtained. The method was applied on the certified reference materials (CRMs) i.e. NBS-362 and NBS-364 (special low alloy steel), for the determination of cobalt and the results were in good agreement with the certified values.