A novel immunosensor based on immobilization of hepatitis B surface antibody on platinum electrode modified colloidal gold and polyvinyl butyral as matrices via electrochemical impedance spectroscopy.

Hepatitis B surface antibody (HBsAb) was immobilized to the surface of platinum electrode modified with colloidal gold and polyvinyl butyral (PVB) as matrices to detect hepatitis B surface antigen (HBsAg) via electrochemical impedance spectroscopy (EIS). The electrochemical measurements of cyclic voltammetry and impedance spectroscopy showed that K(4)[Fe(CN)(6)]/K(3)[Fe(CN)(6)] reactions on the platinum electrode surface were blocked due to the procedures of self-assembly of HBsAb-Au-PVB. The binding of a specific HBsAb to HBsAg recognition layer could be detected by measurements of the impedance change.

Novel potentiometric immunosensor for hepatitis B surface antigen using a gold nanoparticle-based biomolecular immobilization method.

A novel potentiometric immunosensor for the detection of hepatitis B surface antigen has been developed by means of self-assembly to immobilize hepatitis B surface antibody on a platinum disk electrode based on gold nanoparticles, Nafion, and gelatin as matrices in this study. The modification procedure of the immunosensor was further characterized by using cyclic voltammetry and the enzyme-linked immunosorbent assay (ELISA) method. The detection is based on the change in the electric potential before and after the antigen-antibody reaction.

Ion-pair complex-based solvent extraction combined with chemiluminescence determination of chlorpromazine hydrochloride with luminol in reverse micelles.

A new chemiluminescence (CL) method is proposed for the determination of chlorpromazine hydrochloride, which is based on the dichloromethane solvent extraction of ion-pair complex of tetrachloroaurate(III) with chlorpromazine hydrochloride and luminol chemiluminescence detection in a reversed micellar medium formed by the cation surfactant cetyltrimethylammonium bromide in a dichloromethane-cyclohexane (1:1 V/V)-water (0.3 mol/L Na2CO3 buffer solution with the pH of 11.5).

Binding study of drug with bovine serum album using a combined technique of microdialysis with flow-injection chemiluminescent detection.

Microdialysis coupled with flow-injection chemiluminescence (FI-CL) has been developed to determine the binding parameters of a drug binding to protein by using antibiotic tetracycline hydrochloride binding to bovine serum albumin as a model system. The drug and protein were mixed in different molar ratios in 0.067 M phosphate buffer, pH 7.

An epidemic model in a patchy environment.

An epidemic model is proposed to describe the dynamics of disease spread among patches due to population dispersal. We establish a threshold above which the disease is uniformly persistent and below which disease-free equilibrium is locally attractive, and globally attractive when both susceptible and infective individuals in each patch have the same dispersal rate. Two examples are given to illustrate that the population dispersal plays an important role for the disease spread.

Simulating the SARS outbreak in Beijing with limited data.

We propose a mathematical model to simulate the SARS outbreak in Beijing. The model consists of six subpopulations, namely susceptible, exposed, quarantined, suspect, probable and removed, as China started to report SARS cases as suspect and probable separately from April 27 and cases transferred from suspect class to probable class from May 2. By simplifying the model to a two-compartment suspect-probable model and a single-compartment probable model and using limited data, we are able to simulate the SARS outbreak in Beijing.

Microscopic determination of tetracycline based on aluminum-sensitized fluorescence of a self-ordered ring formed by a sessile droplet on glass slide support.

A fluorescent microscopic determination of trace amount of tetracycline is reported based on the aluminum-sensitized fluorescence effect of a self-ordered ring formed by a sessile droplet on glass slide support. Since the evaporative loss of the solvent from the edge wedge of the droplet that is spotted on a hydrophobic-treated glass slide, an outward capillary flow of the interior solvent of the droplet occurs. The resulted outward capillary flow then carries the solute to the perimeter of the droplet spot where the solute accumulates to form a fluorescent self-ordered ring (SOR).

A novel chemiluminescence method for determination of terbutaline sulfate based on potassium ferricyanide oxidation sensitized by rhodamine 6G.

This work reports a novel flow injection-chemiluminescence (FI-CL) system for determination of terbutaline sulfate, a drug for treatment of asthma and chronic obstructive pulmonary disease (COPD). It is based on the reaction of potassium ferricyanide with terbutaline sulfate in sodium hydroxide medium sensitized by the fluorescent dye rhodamine 6G. With the peak height as a quantitative parameter applying optimum working conditions, terbutaline sulfate is determined over the range of 0.

Resonance light scattering imaging detection of proteins with alpha,beta,gamma,delta-tetrakis(p-sulfophenyl)porphyrin.

A resonance light scattering (RLS) imaging technique was introduced to measure the light scattering of aggregation species induced by proteins, and thus a method of detecting proteins in the range of picograms was proposed. In acidic medium, J-aggregation of alpha,beta,gamma,delta-tetrakis(p-sulfophenyl)porphyrin (TPPS(4)) in the presence of proteins occurs, resulting in strong RLS signals characterized at 490 nm. Under the excitation of a 488-nm light beam of argon ion laser source, the scattered light of single J-aggregation species could be observed with a common microscope, and the images could be captured with a cooled charge-coupled device camera.

An on-line galvanic cell-generated electrochemiluminescence and flow injection determination of calcium in milk and vegetables.

An on-line Ag/Al galvanic cell was studied and employed to generate electrochemiluminescence (ECL) of calcein blue. The potential of the galvanic cell could be adjusted by varying the components of flow reagent or by using different metals to substitute for Ag or Al. The reported cell exhibited perfect capability of supplying a stable potential for ECL generation.

Determination of berberine by measuring the enhanced total internal reflected fluorescence at water/tetrachloromethane interface in the presence of sodium dodecyl benzene sulfonate.

A highly sensitive method for determination of berberine is proposed based on the measurements of total internal reflected fluorescence (TIRF) at water/ tetrachloromethane (H(2)O/CCl(4)) interface. In the pH range of 2.6-5.

Flow-injection determination of ornidazole by chemiluminescence detection based on a luminol-ferricyanide reaction.

A flow-injection analysis (FIA) with a chemiluminescence detection method was developed for the determination of ornidazole based on the inhibition intensity of chemiluminescence from the luminol-ferricyanide system. Under the condition of 1.0 x 10(-3) mol/L luminol and 5.

[A comparison study on the species diversity between the gap and non-gap in Jinyun Mountain].

The species diversity and community stability of gap and non-gap stands in Jinyun Mountain were studied by using species richness index(dGL), Shannon-Weiner index, Pielou evenness index(J), Simpson index(D), ecological dominance(lambda), evenness-dominance-abundance index(Z) and community dominance(C). The results showed that the dGL, H', J and D calculated by individuals numbers in gap are 12.14, 4.

Determination of proteins with Fast Red VR by a corrected resonance light-scattering technique.

A simple corrected resonance light-scattering (CRLS) technique was established to correct for any distortion of the resonance light scattering (RLS) spectra resulting from molecular absorption. By using an absorption cell holder to change the propagation direction of the incident light beam of a common spectrofluorometer, the molecular absorption was directly measured through a spectrofluorometer. With measurements of the CRLS signals of the interaction of Fast Red VR (FRV) and proteins, we proved that the present correction for the RLS spectra in terms of the molecular absorption of excitation and scattering radiation can improve the detection sensitivity by about two fold.

[On-line determination of transitional metal ions by low-pressure ion chromatography with chemiluminescence detection].

The separation and determination of five transitional metal ions, Co2+, Cu2+, Mn2+, Fe2+ and Cr3+ by low-pressure ion chromatography with chemiluminescence detection were investigated for the first time. The separation was carried out on a C3 ion chromatographic column by using a step gradient elution with the mobile phase of oxalic acid-citric acid solution. The five transitional metal ions could be separated simultaneously.

Determination of cationic surfactants in water samples by their enhanced resonance light scattering with azoviolet.

A simple assay of cationic surfactants in water samples was developed based on the measurements of enhanced resonance light scattering (RLS). At pH 6.09 and ionic strength 0.

Fluorescence assay based on preconcentration by a self-ordered ring using berberine as a model analyte.

A novel assay for trace amounts of fluorescent analytes is proposed based on the assembly of a self-ordered ring (SOR) through capillary flow in a sessile droplet on a glass slide support. After solvent evaporation of the sessile droplet containing a fluorescent analyte on a hydrophobic-treated glass slide, an outward capillary flow of the solvent from the interior of the droplet occurs. The resultant outward capillary flow then carries the analyte to the perimeter of the droplet spot where the analyte deposits and forms a fluorescent SOR.

A sensitive and selective assay of nucleic acids by measuring enhanced total internal reflected resonance light scattering signals deriving from the evanescent field at the water/tetrachloromethane interfacet.

A total internal reflected resonance light scattering (TIR-RLS) technique, the coupling of resonance light scattering (RLS) technique with total internal reflected light at the interface of two immiscible liquids, where the steep change of the refractive indexes occurs to result in an evanescent field, is proposed with the characteristics of separation and enrichment properties of analytes and direct use of oil-soluble reagents free from surfactants. At pH 8.69 and ion strength 0.

Chemiluminescence biosensor chip based on a microreactor using carrier air flow for determination of uric acid in human serum.

A chemiluminescence biosensor on a chip coupled to a microfluidic system and a microreactor is described in this paper. The chemiluminescence biosensor measured 25 x 75 x 6.5 mm in dimension, and was readily produced in an analytical laboratory.

Direct quantification of human serum albumin in human blood serum without separation of gamma-globulin by the total internal reflected resonance light scattering of thorium-sodium dodecylbenzene sulfonate at water/tetrachloromethane interface.

A direct quantification of human serum albumin (HSA) in blood serum samples without separation is proposed based on the measurements of total internal reflected resonance light scattering (TIR-RLS) at water/tetrachloromethane (H(2)O/CCl(4)) interfaces. In the pH range of 6.37-6.

A resonance light-scattering determination of proteins with fast green FCF.

The interaction of Fast Green FCF (FCF) with proteins (including bovine serum albumin (BSA), human serum albumin (HSA), pepsin (Pep) and alpha-chymotrypsin (Chy), and lysozyme (Lys)) was characterized by enhanced resonance light-scattering (RLS) measurements using a common spectrofluorometer. The enhanced RLS signals of FCF by proteins at 279.0 nm were obtained, and the mechanism of the RLS enhancement was considered in terms of the effects of the pH and ionic strength on the interaction.

Determination of proteins by their enhancement of resonance light scattering by fuchsine acid.

Based on the measurement of the enhancement of resonance light scattering (RLS) of fuchsine acid (FSA) by proteins, a novel sensitive assay of proteins in body fluid samples has been developed. Proteins, including bovine serum albumin (BSA), human serum albumin (HSA), pepsin (Pep), alpha-chymotrypsin (Chy), lysozyme (Lys), and cellulase (Cel), can bind to fuchsine acid (FSA), resulting in enhanced RLS signals at 277.0 nm.

Determination of DNA with cetyltrimethylammonium bromide by the measurement of Resonance Light Scattering.

A simple assay of DNA was developed based on the measurements of enhanced signals of Resonance Light Scattering (RLS) of cetyltrimethylammonium bromide (CTMAB) by DNA. The enhanced RLS signals, measured by simultaneously scanning the excitation and emission monochromators of a common spectrofluorometer with lambda ex = lambda em, was optimized for the DNA assay with CTMAB. On the conditions of pH 2.

Total internal reflected resonance light scattering determination of chlortetracycline in body fluid with the complex cation of chlortetracycline-europium-trioctyl phosphine oxide at the water/tetrachloromethane interface.

A highly selective method of chlortetracycline (CTC) is proposed on the basis of the measurements of total internal reflected resonance light scattering (TMR-RLS) at water/tetrachloromethane (H20/CCl4) interfaces. In the pH range of 7.54-8.

A flow injection chemiluminescence system for the determination of isoniazid.

A chemiluminescence (CL) flow system is described for the determination of isoniazid based on its enhancement on the chemiluminescence (CL) emission produced upon mixing a hexacyanoferrate(III) solution with an alkaline luminol solution. The system responds linearly to isoniazid concentration in the range 0-1 mg/L with a detection limit (3sigma) of 0.03 microg/L, relative standard deviation (RSD) of 1.