Enzyme Immunoassay of Thyroid-Stimulating Hormone Using Dried Blood Samples a Simple Technique of Screening for Congenital Hypothyroidism

Abstract

A method for enzyme imnunoassay of thyroid-stimulating hormone (TSH) in dried blood spotted onto filter paper has been developed. TSH was conjugated to horse-radish peroxidase according to Nakane's method. Separation of the bound and free fractions was obtained by a double antibody solid phase method using polyacetal beads which were coated with the purified IgG fraction from goat anti-rabbit IgG serum. p-Hydroxyphenyl propionic acid was used as substrate for the fluorophotometric assay of peroxidase activity. The assay sensitivity is 0.07, μU TSH/assay tube, which is equivalent to μU/ml when five 3 mm discs of dried blood spot are assayed. TSH values in dried blood samples obtained by this method correlate well with those of serum samples obtained by radioimmunoassay (r=0.89). The coefficients of variation were 6.8 to 13.4% (within assay) and 5 to 40% (between assay). The enzyme immunoassay of TSH presented here is applicable to the mass-screening for congenital hypothyroidism of neonate.     

Determination of Primaquine in Whole Blood and Finger-Pricked Capillary Blood Dried on Filter Paper Using HPLC and LCMS/MS

Primaquine (PQ) is the only 8-aminoquinoline antimalarial drug in clinical use because of its unique action on hypnozoites and gametocytes of Plasmodium species. We report here simple, sensitive and specific assay methods for the determination of PQ in human whole blood and dried blood spot (DBS) samples using high-performance liquid chromatography and liquid chromatography-mass spectrometry, respectively. Sample preparation was performed by a single or two-step liquid-liquid extraction with organic solvents. For whole blood analysis, separation was obtained on a reversed-phase C18 column with the mobile phase consisting of 0.25 % diethylamine and acetonitrile (7:3, v:v) running at a flow rate of 1.0 ml min^?1. UV detection was at the wavelength 263 nm. For DBS analysis, separation was obtained on a reversed-phase column with the mobile phase consisting of methanol and 0.1 formic acid (1:3, v:v) running at a flow rate of 0.5 ml min^?1. The selected ions generated by electrospray ionization were detected using mass spectrometer. Good precision and accuracy (both within-day and day-to-day assays) were obtained at the concentration ranges under investigation. Limits of quantification for PQ were accepted as 25 ng ml^?1 using 500 μl whole blood and 5 ng ml^?1 using 80 μl DBS samples. The mean recoveries for PQ and internal standard pyrimethamine (PYR) for both whole blood and DBS were over 70 %. The methods were successfully applied for a clinical pharmacology study of PQ in patients with Plasmodium vivax. Excellent correlation (r ²  = 0.997) was observed between the analysis of PQ in paired whole blood and DBS samples.     

Improvement of an Enzyme Immunoassay for the Determination of Mercury(II)

Three systems were tested for the optimization of a heterogenous non-competitive enzyme immunoassay (EIA) for the determination of Hg (II). The sensitivity of the non optimized Hg-EIA with a detection limit of 2.1 μg/L Hg (II) was improved by an avidin-biotin-complex (ABC) amplification system to a 2-fold lower detection limit (1.1 μg/L Hg (II)). A conventional competitive ElA with the competition reaction between bound and free Hg (II) for antibody (ab) binding sites yielded a detection limit of 1.0 μg/L Hg (II). Further improvement of sensitivity could be achieved by a competitive displacement EIA. In this case ab molecules bound to immobilized haptens are displaced in the next step by free Hg (II). The detection limit of the displacement approach is 0.4 μg/L Hg (II).     

The Application of an Enzyme Electrode for Blood Glucose Determination in the Automated Flow System

Abstract

An enzyme electrode containing immobilized GOD was utilized in a continuous flow system for the automatical determination of glucose. The advantages of kinetic measurement of H₂ O ₂ are used. Characteristic parameters of device and results in routine are shown. Particular advantages are: low requirement on material (20 μl blood, < l μg GOD/measurement) and time (60 samples/h at 15 sec response time) as well as sufficient precision and accuracy (S % - serial: < 2 %).     

GOx@ZIF‐8(NiPd) Nanoflower: An Artificial Enzyme System for Tandem Catalysis

We report a facile approach to prepare an artificial enzyme system for tandem catalysis. NiPd hollow nanoparticles and glucose oxidase (GOx) were simultaneously immobilized on the zeolitic imidazolate framework 8 (ZIF‐8) via a co‐precipitation method. The as‐prepared GOx@ZIF‐8(NiPd) nanoflower not only exhibited the peroxidase‐like activity of NiPd hollow nanoparticles but also maintained the enzymatic activity of GOx. A colorimetric sensor for rapid detection of glucose was realized through the GOx@ZIF‐8(NiPd) based multi‐enzyme system. Moreover, the GOx@ZIF‐8(NiPd) modified electrode showed good bioactivity of GOx and high electrocatalytic activity for the oxygen reduction reaction (ORR), which could also be used for electrochemical detection of glucose.     

Development of a Sensitive Luminometric Immunoassay for Determining Baseline Seasonal Changes in Serum Vitellogenin Levels in Male Flounder (Pleuronectes Yokohamae)

Abstract

Vitellogenin is a sensitive biomarker used to study the effects of artificial estrogens in aquatic environments. We developed and optimized a luminometric immunoassay that was able to detect trace amounts of vitellogenin in the serum of male flounder collected from an uncontaminated reference site. The lowest measurable concentration of vitellogenin in the serum was approximately 0.08 ng/ml with purified protein diluted in buffer. The reproducibility of the vitellogenin measurements was determined by the analysis of triplicate samples and found to be about 5.3%, based on serum samples containing vitellogenin at 2.0 ng/ml. This method was successfully applied to samples collected from an uncontaminated reference site for the monitoring of baseline levels of serum vitellogenin in male flounder.     

Automated SIA System Using an Array of Potentiometric Sensors for Determining Alkaline‐Earth Ions in Water

This work deals with the simultaneous determination of Mg²⁺, Ca²⁺, and Ba²⁺ in water using a PVC‐membrane potentiometric sensor array and multivariate calibration, in what is known as electronic tongue. The subsequent processing of the data was based on the use of a multilayer artificial neural network (ANN). The information needed for training or generation of the model was obtained with the aid of an automated analytical system based on the Sequential Injection Analysis (SIA) technique. The modeling ability was verified with an external set of standards, and next the determinations were performed in real samples of mineral waters, where close results for Mg²⁺ and Ca²⁺ were obtained to those obtained with reference methods. The determination of Ba²⁺ can be considered as semi‐quantitative for synthetic samples – due to the absence of Ba²⁺ in mineral waters, its concentration in real samples was not measured.     

2004年理科综合能力测试(山西)试卷分析与试题评价报告依托基础考查能力结合实际定制试题

自1999年开始的3+X高考改革,已进入第6个年头,其中做为高考改革中人们极为关注的高考科目改革,即现在绝大多数省市区采用的3+文科综合/理科综合模式,已进行了5年7次.回顾5年理综试题的状况,特别是2004年理综试题的特点、分布、难度、区分度,结合课程改革的进展,会对我们有不少的启示.     

Evaluation of Light Fluence Distribution Using an IR Navigation System for HPPH-mediated Pleural Photodynamic Therapy (pPDT)

Uniform light fluence distribution for patients undergoing photodynamic therapy (PDT) is critical to ensure predictable PDT outcomes. However, current practice when delivering intrapleural PDT uses a point source to deliver light that is monitored by seven isotropic detectors placed within the pleural cavity to assess its uniformity. We have developed a real-time infrared (IR) tracking camera to follow the movement of the light point source and the surface contour of the treatment area. The calculated light fluence rates were matched with isotropic detectors using a two-correction factor method and an empirical model that includes both direct and scattered light components. Our clinical trial demonstrated that we can successfully implement the IR navigation system in 75% (15/20) of the patients. Data were successfully analyzed in 80% (12/15) patients because detector locations were not available for three patients. We conclude that it is feasible to use an IR camera-based system to track the motion of the light source during PDT and demonstrate its use to quantify the uniformity of light distribution, which deviated by a standard deviation of 18% from the prescribed light dose. The navigation system will fail when insufficient percentage of light source positions is obtained (<30%) during PDT.     

Analysis of Free and Total Glycerol in Biodiesel Using an Electrochemical Assay Based on a Two‐Enzyme Oxygen‐Electrode System

In this work, an electroenzymatic methodology based on two coupled enzymatic activities (glycerokinase and glycerol‐3‐phosphate oxidase) was developed using an oxygen Clark‐type electrode for the determination of free and total glycerol in biodiesel samples. The enzymatic conversion of glycerol consumes oxygen, which is measured amperometrically in a Clark‐type electrode and correlated with the concentration of glycerol in the sample. The electroenzymatic method proposed showed a good linear correlation coefficient (R=0.9990) with a linear response in the concentration range of 6.25×10^?5 to 6.25×10^?4% (w/v) and limits of detection and quantification at 1.0×10^?5% and 3.0×10^?5% (w/v), respectively. Good correlations were found between the results obtained in this work and those by the gas chromatography technique (R=0.9994). The proposed method was shown to be promising for the analysis of glycerol in biodiesel samples, with a simple and inexpensive methodology compared with the gas chromatography technique.     

Lipase‐Catalyzed transformation of Poly(trimethylene carbonate) into Cyclic Monomer,Trimethylene Carbonate: A New Strategy for Sustainable Polymer Recycling Using an Enzyme

The enzymatic degradation and polymerization using an enzyme were carried out with respect to the establishment of a sustainable chemical recycling system for poly(trimethylene carbonate) [P(TMC)] which is a potentially biodegradable synthetic plastic. The enzymatic transformation of P(TMC)s having an M_n of 3000~48000 using Candida antarctica lipase (lipase CA) in acetonitrile at 70 °C afforded the corresponding cyclic monomer, trimethylene carbonate (TMC: 1,3‐dioxan‐2‐one), in a yield of up to 80%. Thus obtained TMC readily polymerized again using both fresh lipase CA and recovered lipase CA.     

Determination of Iron (II) in Water by a Spectrophotometric Method After Preconcentration on an Organic Solvent-Soluble Membrane Filter

Abstract

A solvent-soluble membrane filter is proposed for a simple and rapid preconcentration and spectrophotometric determination of iron (II), which was collected on a nitrocellulose membrane filter as an ion-associate of the cationic complex of iron (II)-1,10-phenanthroline with an anionic surfactant of dodecyl sulfate. The ion-associate collected was dissolved in 5 ml of 2-methoxyethanol together with the filter. The color intensity due to the ion-associate in the resulting solution was measured at 510 nm against a reagent blank. Beer's law is obeyed in the range 1–15 μg Fe (II) in 5 ml of solvent with excellent reproducibility, and detection limits better than 0.5 μg dm^?3 as Fe (II) can be achieved. The diverse components normally present in water do not interfere when proper masking reagent is added. The proposed method has been applied to the analysis of water samples from several sources such as river water, ground water and tapwater samples, the recoveries of the iron (II) added to the samples are quantitative, and results found are satisfactory.     

氟化物体系三价铬镀铬工艺的研究

采用恒电位法在氟化物体系中镀铬,以铅银合金为阳极,20号不锈钢片为阴极,探讨了电流密度、温度、pH值、时间等因素对电镀效率的影响.研究表明:在氟化物体系中,镀液温度为30-40℃,pH=1.65,电流密度=30 A/dm2,反应时间在15 m in时,即能得到细致光亮结合力牢固的金属铬镀层,并且电镀效率达到29.46%.     

An integrated analytical approach for characterizing an organic residue from an archaeological glass bottle recovered in Pompeii (Naples, Italy)

Within the framework of an Italian research project aimed at studying organic residues found in archaeological objects from the Roman period, the chemical composition of the contents of several glass vessels recovered from archaeological sites from the Vesuvian area (Naples, Italy) was investigated. In particular, this paper deals with the study of an organic material found in a glass bottle from the archaeological site of Pompeii using a multi-analytical approach, including FT-IR, direct exposure mass spectrometry (DE-MS) and GC-MS techniques. The overall results suggest the occurrence of a lipid material of vegetable origin. The hypothesis that the native lipid material had been subjected to a chemical transformation procedure before being used is presented and discussed.     

Flow-Batch Method with a Sequential Injection System for Spectrophotometric Determination of Selenium(IV) in Selenium-Enriched Yeast Using o-Phenylenediamine

A precise, accurate, and reliable flow-batch spectrophotometric method for the determination of selenium (IV) was developed using o-phenylenediamine as a reagent with a sequential injection monosegmented flow system incorporating a simple heating unit. The reaction zones of selenium(IV) and o-phenylenediamine were mixed and heated in a chamber at 62°C for 5 minutes. The piaselanol complexes were then detected at a maximum absorption wavelength of 335 nm. In-line single standard calibration and standard addition procedures were developed employing the monosegmented flow technique. Under the optimized conditions, a linear calibration graph in a range of 0.1–4.0 mg L^?1 selenium (IV) was obtained with limits of detection and quantitation of 0.01 and 0.1 mg L^?1, respectively. Relative standard deviations were 2% [for both 0.1 and 0.5 mg L^?1 selenium (IV) (n = 11)]. A sample throughput of 2 h^?1 using four standard addition levels was achieved. The developed system was successfully applied to raw selenium-enriched yeast samples. The analyses performed by the developed method agreed well with those obtained from a standard inductively coupled plasma mass spectrometry method.     

An innovative strategy for immobilization of receptor proteins on to an optical fiber by use of poly(pyrrole-biotin)

We report an innovative and useful procedure for immobilization of antibodies on to a fiber-optic silica surface. The procedure consists in the chemical oxidation of pyrrole-biotin monomers that are readily deposited as a thin film of poly(pyrrole-biotin) polymer on to the end-face of the fiber. The film was shown to be sufficiently translucent to enable photon coupling within the fiber transducer and its presence was demonstrated by means of fluorescent micrographs of bound rhodamine-labeled avidin. Fiber-optics modified with cholera toxin B subunit molecules were tested for sensitivity, non-specificity, and overall practicality. It was shown that the fiber-optic immuno-assay for the detection of anti-cholera toxin antibody was up to three orders of magnitude more sensitive than the classical enzyme-linked immunosorbent assay (ELISA).     

Vapochromism of a Pyrrolizinato-nickel(II) Complex Incorporated in Polyvinylbutyral. An Optochemical Detecting System for Alcohols in Air

The bis(1,2,6,7-tetracyano-3,5-dihydro-3,5-diiminopyrrolizinido)nickel(II ) complex (NiL2, L = C11H2N7-) has been incorporated as dispersed monomer in polyvinylbutyral (PVB) at a fairly high concentration (0.021 M). NiL2/PVB spin coated thin films (thickness, 2 m) on glass and silicon and evaporated free standing thicker films (thickness, 50 m) have been studied by means of absorption or reflectivity visible as well as infrared spectroscopy. The light-blue NiL2/PVB film fades slightly on heating (for 7 min at 90 °C) and remains as such after cooling to room temperature. The optical spectrum of the thermally activated NiL2/PVB system, in contact with organic solvent vapors at room temperature, changes with time evolving towards the initial spectrum before the thermal treatment. The system is therefore amenable for sensing organic solvents in air. Several ordinary solvents have been tested. After 12 min exposure to air saturated with vapor a steady-state absorbance signal at the most sensitive wavelength (661 nm) is reached for any tested solvent. The system is most sensitive to alcohols. Response cycles are reported for methanol as solvent.