Flow-injection Chemiluminescence Determination of Catecholamines

Catecholaminesarenowwidelyusedinthetreatmentofbronchialasthma,hypertension,heartfailureassociatedwithorganicheartdiseases,andcardiacsurgery'.Thedeterminationofcatacholaminesinpharmaceuticalpreparationshasappearedespeciallyattractive.Chemiluminescence(CL)hasbeenexploitedinanumberofanalyticalapplicationsowingtoitsgreatsensitivity.SomeCLreactionshavenotfoundmanyapplicationsduetotheinstabilityofoxidationreagentssuchashypochlorite.WeproposedthatunstablereagentsrequiredforCLreactioncanbegenerated…     

Liposome Immunoassay for Determination of Phenytoin

Inthispaper,arapid,sensitive,andsimpleliposomeimmunoassay(LIA)lbrdetectingphenytoinhasbeenestablished.Phenytoinisuscdtocurecpilepsy,butinclinicalpractice,theefficientconcentrationofphenytoininpatient'sseraisverynarrow,about1O~2Opg/ml.Iftheconcentrationofphenytoininserumislessthantheefficientconcentration,thereisnoeffectofmedicine.Butiftheconcentrationrangewerc2O~4Ollg/ml,themedicinecouldbringsideeffect.Ifthcconcentrationbecomesgreater,thenitcancausepoisoning.Becausetherearemanyfactorswhich…     

Determination of the Atomic Weight of Germanium

IntrOduedon:ThemodPodedcattalcwegheqailtheelementsisPr~thatofge~Um,A.(Ge.~cuous~aslargaso.o4ekiStS~nthe~Ge)detenninedtymass~andthatfoundtytheclassitalchthetalInethod').ThePreSentinveedghonaimsatCarryinouathetutetheonmeasurmentusingthetrueisotwicbooofGa6,nl=l.5o676(39)fOundtyMachlanetaLinacali~tnass~cmecmenP,wherethevaluewithintbebracketsindibestheerrorofthelaStbodigitS.ooumandge~umareneighborsintheperiedcSystmQfelements.TheformrisbinpelidicandhasisotpewithmassnUmbosas69and71,whereas~u…     

Resonance Light Scattering Imaging Determination of Heparin

Light scattering submicroscopic particles such as metallic particles and particles of other composition have high-producing power and can be used as fluorescent analogs and tracers labels in clinical and biological applications1-3. Their light scattering …     

Determination of the Absolute Configuration of Rohitukine

The absolute configuration of rohitukine, isolated from the stem-bark of Dysoxylum binectariferum, was determined to be 5,7-dihydroxy-2-methyl-8-[4-(3S, 4R-3-hydroxy-1-methyl)-piperidinyl]-4H-l-benzopyran-4-one by X-ray crystallographic analysis on the crystal of,4-bromobenzoyl derivatives of rohitukine. At the same time, the modified Mosher method was proved to be unsuitable for determining the absolute configuration of C-3‘ position in rohitukine.     

Determination of the Atomic Weight of Samarium

Introduction:Aftergainingexperienceintheisotopicratiomeasurementofsamarium(1),weproceededtocarryoutaprecisedeterminationofitsatomicweightandobtainedavalueofA,(Sm)agreeingperfectlywiththatobservedbyLugmair<'>andWasserburg<'>.Sampleofsamarium:Asampleofsamarium,99+%Sm,O,,wassuppliedbytheResearchInstituteofRareEarths,NanchangUniversity,Jiangsi.Itwasextractedfromthemineral,rareearthadsorptionkaolinite,anextensivedepositintheprovince-Thematerialwasfurtherpurifiedbyextractionchromatographythrou…     

Determination of β-adrenergic agonists by hapten microarray

The use of highly active β-agonists as growth promoters is not appropriate because of the potential hazard for human and animal health. To investigate the residue level of these β-agonists, hapten microarrays were employed for clenbuterol (CLB), ractopamine (RAC) and salbutamol (SAL) residue analysis. CLB, RAC and SAL conjugates were immobilized on the slides, which were precoated by agarose film to construct hapten microarrays, and then the corresponding monoclonal antibodies of these β-agonists and the standards or samples were introduced for indirect competitive immunoassay. Finally, Cy3-labeled secondary antibody was employed to indicate the antigen-antibody complex. The fluorescence intensity of each spot was imaged and recorded, and the calibration curve of each analyte was obtained by plot fluorescence intensity against different standard concentrations. Compared to the ELISA, the hapten microarray method was more sensitive, which got the detection limits 0.09 μg/L for CLB, 0.50 μg/L for RAC, and 0.01 μg/L for SAL. What's more, with the recovery rate between 96.5% and 106.4%, and the coefficient of variation below 10%, the proposed hapten microarray method was shown to be both quantitative and reproducible.     

Determination of Average Wall Thickness of Mesoporous Silica

Mesoporous silica formed by the condensation of silica oligomers around self-assembled surfactant micelle templates has recently attracted much interest owing to its potential for use in catalytic or adsorbent applications1. Much attention has been focused on characterization of its pore structure by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), N2 adsorption, small angle X-ray scattering (SAXS) et al., but seldom concerning its average wall thickness2-7. This shor…     

Determination of α-Amanitin in Serum by HPLC

Abstract

A reverse-phase high-performance liquid chromatographic method for the quantitative determination of α-amanitin in serum of poisoned patients is described and discussed. The methodology developed is simple and rapid with a minimum of sample preparation steps required. Detection is very sensitive, allowing quantitation of 25 ng of α-amanitin/ml of serum. The technique described is a useful tool to determine the severity of Amanita phalloides intoxication during the first 24 h after ingestion of poisonous mushrooms.     

Enzymatic Determination of Urinary Total 17β-Hydroxysteroids

Abstract

An enzymatic determination of urinary total 17β-hydroxysteroids is described. The principle of the method is as follows: after hydrolysis with β-glucuronidase and solvolysis, the ethyl acetate layer, which is washed with alkaline solution and water, is transferred to two test tubes, then each of them is evaporated. To one test tube is added 3β,17β-hydroxysteroid dehydrogenase (EC 1.1.1.51, from P. testosteroni), NAD⁺, 2-ρ-iodophenyl-3-ρ-nitrophenyl-5-phenyltetrazolium chloride (INT), and diaphorase (EC 1.6.99.2, from C. kluyveri) for determination of total 3β,17β-hydroxysteroids. To another test tube is added 3β-hydroxysteroid oxidase (EC 1.1.3.6, from B. sterolicum) for determination of total 3β-hydroxysteroids. The value of 17β-hydroxysteroids is calculated by subtracting the value for 3β-hydroxysteroids from the value for the 3β,17β-hydroxysteroids.     

Determination of diquat by flow injection–chemiluminescence

A simple, economic, sensitive and rapid method for the determination of the pesticide diquat was described. This new method was based on the coupling of flow injection analysis methodology and direct chemiluminescent detection; to the authors’ knowledge, this approach had not been used up to now with this pesticide. It was based on its oxidation with ferricyanide in alkaline medium; significant improvements in the analytical signal were achieved by using high temperatures and quinine as sensitiser. Its high throughput (144 h⁻¹), together with its low limit of detection (2 ng mL⁻¹), achieved without need of preconcentration steps, permitted the reliable quantification of diquat over the linear range of (0.01–0.6) μg mL⁻¹ in samples from different origins (river, tap, mineral and ground waters), even in the presence of a 40-fold concentration of paraquat, a pesticide commonly present in the commercial formulations of diquat. Figure Quartz luminometer cell     

Mitoxantrone Determination by 1,5-order Differential Stripping Voltammetry

IntroductionMXTbelongstoanewstructuralclassofantineoplasticagentswithantithrombinstructure.ItcanmakecellsinactivebycombiningwiththeirDNAandpreventthenucleicacidsfrombeingsynthesized,thushavinganantitumoreffect.MXThasbeenusedforantitumorexperimentsonrail.Overtheyears,variousmethodshavebeenreportedforthedeterminationofMXT.Thesemethodsincludechromatography'andimmunology'.However,theyareverycomplicatedandnotsensitiveenoughforthedeterminationofMXTincertainsamples.Theapplicabilityofpolarograp…     

Determination of Thyroxine with Capillary Electrophoretic Enzyme Immunoassay

Capillary electrophoretic immunoassay (CEIA) is a new analytical technique1,2. In CEIA, the detection methods were UV absorbance detection1 and laser induced fluorescence detection (LIF)2. However, The UV detection is lack of sensitivity. The LIF is difficult to use due to its high cost, and furthermore, most biological fluids are strongly luminescent when excited by the laser in the blue or green region of the spectrum. In our present work, a capillary electrophoretic enzyme immuno…     

Flow-injection Chemiluminescence Determination of Trace Calf Thymus DNA

A flow injection procedure for the determination of calf thymus DMA (CT DNA) over the range 2.1x10-6~2.1x10-1 B.g mL-1 is described, based on measurement of the enhanced chemiluminescence emission of rhodamine B-Ce(IV) system, activated by imidazole-HCl buffer solution. This method is highly sensitive, with the linearity range broadened to five orders of magnitude. It has been applied to determine CT DNA in synthetic sample with satisfactory results.     

Determination of thorium with DBF-arsenaz by flow-injection analysis

A sensitive,selective,rapid,simple,and convenient method for the determination of thoriumwas developed.The method was based on the color reaction of thorium with DBF-arsenazo in astrong acidic medium (4 mol/L HCI).The flow-injection technique was used with an automated flow-injection analyzer.Beer's law was obeyed in the range of 0—1.4 μg/mL.The relative standarddeviations were less than 1%.