title stringlengths 0 1.13k | abstract stringlengths 1 15.7k | PMID int64 22 36.5M |
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Simultaneous determination of l-thyroxine (l-T(4)), d-thyroxine (d-T(4)), and l-triiodothyronine (l-T(3)) using a sensors/sequential injection analysis system. | Requirements of high purity and enantiopurity for the raw materials of active substances used for the pharmaceutical formulations involved utilization of high reliable analytical techniques for the analysis of the active compound. Sequential injection analysis system with electrochemical sensors as detectors proved to ... | 18,969,581 |
Chemiluminescence from the oxidation of urea and ammonia with hypobromite and N-bromosuccinimide. | The spectral distribution for the chemiluminescent oxidation of ammonia with hypobromite is significantly different to that for the oxidation of ammonia with N-bromosuccinimide. Therefore, in contrast to the assumptions of several authors, the action of N-bromosuccinimide is not solely derived from the in situ formatio... | 18,969,601 |
A critical examination of sorbent extraction pre-concentration with spectrophotometric sensing in flowing systems. | In this paper, the solid-phase spectrophotometric concept is critically examined in flow systems exploiting a dedicated microcolumn-based optical sensor packed with octadecyl chemically-modified silica gel. The flow configuration integrates matrix separation with pre-concentration and on-column sensing of non-polar com... | 18,969,602 |
Direct determination of Ge in hot spring waters and coal fly ash samples by hydride generation-ETAAS. | A method for Ge determination in hot spring water and acid extracts from coal fly ash samples involving hydride generation, trapping and atomisation of the hydride generated from Ir-treated graphite tubes (GTs) has been developed. Hydride was generated from hydrochloric acid medium using sodium tetrahydroborate. Severa... | 18,969,603 |
Copper(II) selective electrochemical sensor based on Schiff Base complexes. | Plasticized membranes using Schiff Base complexes, derived from 2,3-diaminopyridine and o-vanilin have been prepared and explored as Cu(2+)-selective sensors. Effect of various plasticizers viz., dibutyl phthalate (DBP), dioctylphthalate (DOP), chloronaphthalene (CN), tri-n-butylphosphate (TBP) etc. and anion excluder,... | 18,969,605 |
Resonance Rayleigh scattering method for the recognition and determination of double-stranded DNA using amikacin. | In weakly acidic buffer medium, the interaction of amikacin with calf thymus DNA, yeast RNA and denatured DNA has been investigated by using resonance Rayleigh scattering (RRS) technique. The result shows that calf thymus DNA is capable of enhancing the RRS intensity of the amikacin, while yeast RNA and denatured DNA h... | 18,969,613 |
Voltammetric determination of alkaline phosphatase and horseradish peroxidase activity using 3-indoxyl phosphate as substrate Application to enzyme immunoassay. | The use of 3-indoxyl phosphate (3-IP) as an electrochemical substrate for ELISAs with voltammetric detection was investigated. Indirect measurements of alkaline phosphatase (AP) and horseradish peroxidase (HRP) activity in solution were carried out. Picomolar levels of both enzymes can be detected, which enables the de... | 18,969,625 |
Flow-injection chemiluminescence determination of dihydralazine sulfate based on hexacyanoferrate(III) oxidation sensitized by eosin Y. | A novel flow-injection chemiluminescence (CL) method for the determination of dihydralazine sulfate (DHZS) is described. The method is based on the reaction between DHZS and hexacyanoferrate(III) in alkaline solution to give weak CL signal, which is dramatically enhanced by eosin Y. The CL emission allows quantitation ... | 18,969,628 |
The antioxidant activity of wines determined by the ABTS(+) method: influence of sample dilution and time. | The free radical scavenging activity of 42 Spanish commercial wines was determined using the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS(+)). The ABTS(+) radical was generated enzymatically using a horseradish peroxidase and hydrogen peroxide. The presence of wine phenolic compounds cause... | 18,969,632 |
Focused microwave-assisted Soxhlet extraction: devices and applications. | An overview of a new extraction technique called focused microwave-assisted Soxhlet extraction (FMASE) is here presented. This technique is based on the same principles as conventional Soxhlet extraction but using microwaves as auxiliary energy to accelerate the process. The different devices designed and constructed s... | 18,969,643 |
A dual column system using agarose-based adsorbents for preconcentration and speciation of chromium in water. | Three different agarose-based chelating adsorbents with, respectively, iminodiacetic acid (IDA), tris(2-aminoethyl)amine (TREN) and dipicolylamine (DPA) functional groups and an agarose-based anion exchanger (Q-Sepharose), were studied for the separation and preconcentration of Cr(III) and Cr(VI) species in water. Colu... | 18,969,644 |
Automated and manual luminescent assay of antioxidant capacity: analytical features by comparison. | The analytical performances of a manual and a partially automated chemiluminescent (CL) assay, of total antioxidant capacity (TAC) were assessed. In both cases the light emitting reaction involved luminol, horseradish peroxidase and hydrogen peroxyde, but the emission kinetics and the parameters taken into account to c... | 18,969,657 |
Further study on a flow injection on-line multiplexed sorption preconcentration coupled with flame atomic absorption spectrometry for trace element determination. | A further study on a newly developed flow injection (FI) on-line multiplexed sorption preconcentration (MSP) using a knotted reactor coupled with flame atomic absorption spectrometry (FAAS) was carried out to demonstrate its applicability and limitation for trace element determination. For this purpose, Cr(VI), Cu(II),... | 18,969,669 |
A novel ion selective membrane potentiometric sensor for direct determination of Fe(III) in the presence of Fe(II). | A new PVC membrane potentiometric sensor that is highly selective to Fe(III) ions was prepared by using 2-[(2-hydroxy-1-propenyl-buta-1,3-dienylimino)-methyl]-4-p-tolylazo-phenol [HPDTP] as a suitable carrier. The electrode exhibits a linear response for iron(III) ions over a wide concentration range (3.5 x 10(-6) to 4... | 18,969,710 |
Multi-pumping flow systems: an automation tool. | Multi-pumping flow systems (MPFS) are one of the most recent developments in terms of the design, conception and implementation of continuous flow methodologies, for sample and reagent handling and for the automation of analytical procedures. Based on the utilisation of multiple solenoid micro-pumps they enable the con... | 18,969,716 |
A rapid and precise assay for peroxide as 'active oxygen' in products, by flow injection analysis in a high pressure system with spectrophotometric detection. | A simple, rapid and automated assay for 'active oxygen' originating from hydrogen peroxide, or other organic peroxides, in products is presented employing flow injection (FI) analysis. The product is dispersed and peroxide dissolved in a solvent of 5% (v/v) acetic acid, which constitutes the carrier stream. Ammonium mo... | 18,969,726 |
Spectrophotometric determination of bromate by sequential injection analysis. | A simple and rapid on-line spectrophotometric method for the determination of bromate is proposed. The method is based on the reaction of bromate and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-bromo-PADAP) with SCN(-), a red complex is formed and monitored at 550nm. The linear range found is between 0.18 and 3.00... | 18,969,729 |
Flow injection analysis of doxycycline or chlortetracycline in pharmaceutical formulations with pulsed amperometric detection. | A flow injection with pulsed amperometric detection for determination of doxycycline or chlortetracycline in pharmaceutical formulations is described. Doxycycline or chlortetracycline were studied at a gold rotating disk electrode with cyclic voltammetry as a function of pH of supporting electrolyte solution. The optim... | 18,969,737 |
Reduction of hexavalent chromium at solid electrodes in acidic media: reaction mechanism and analytical applications. | The electrochemical detection of hexavalent chromium species was investigated. It was found that Cr(VI) can undergo chemically irreversible reduction in acidic solutions at gold, glassy carbon and boron-doped diamond electrodes. The process was found to be diffusionally controlled at all three electrodes studied. The r... | 18,969,766 |
Preparation and application of a new glucose sensor based on iodide ion selective electrode. | An electrode for glucose has been prepared by using an iodide selective electrode with the glucose oxidase enzyme. The iodide selective electrode used was prepared from 10% TDMAI and PVC according our previous study. The enzyme was immobilized on the iodide electrode by holding it at pH 7 phosphate buffer for 10min at ... | 18,969,768 |
Determination of aliphatic amines in water by gas chromatography using headspace solvent microextraction. | The possibility of applying headspace microextraction into a single drop for the determination of amines in aqueous solutions is demonstrated. A 1mul drop of benzyl alcohol containing 2-butanone as an internal standard was suspended from the tip of a micro syringe needle over the headspace of stirred sample solutions f... | 18,969,788 |
Fourth derivative spectrophotometric determination of fungicide thiram (tetramethyldithiocarbamate) using sodium molybdate and its application. | A procedure has been developed for the direct fourth derivative spectrophotometric determination of tetramethyldithiocarbamate by converting it into its molybdenum complex, which is then extracted in to methyl isobutyl ketone (MIBK). Beer's law is obeyed over the concentration range 24mugmL(-1) in the final solution. T... | 18,969,809 |
Comparison of synchronous and laser-induced fluorescence spectroscopy applied to the Eu(III)-fulvate complexation. | The complexation of europium ion (Eu(III)) with a soil fulvic acid (FA) has been studied at pH 5 in 0.01M NaClO(4) by different experimental methods, i.e. synchronous fluorescence spectroscopy (SyFS) and time resolved laser-induced fluorescence spectroscopy (TRLFS). A series of SyFS quenching spectra was obtained by in... | 18,969,811 |
Comparison of two-typed (3-mercaptopropyl)trimethoxysilane-based networks on Au substrates. | Two-typed (3-mercaptopropyl)trimethoxysilane-based networks which had been used to fabricate biosensors were prepared on Au substrates by two methods: layer-by-layer assembly, and the combination of sol-gel and self-assembly process. The formation mechanism and their surface properties, as well as stabilities were exam... | 18,969,823 |
Development of an immunosensor for the determination of rabbit IgG using streptavidin modified screen-printed carbon electrodes. | Voltammetric enzyme immunosensors based on the employment of streptavidin modified screen-printed carbon electrodes (SPCEs) for the detection of rabbit IgG, as a model analyte, were described. Alkaline phosphatase (AP) and 3-indoxyl phosphate (3-IP) were used as the enzymatic label and substrate, respectively. The adso... | 18,969,836 |
Analysis and speciation of arsenic by stripping potentiometry: a review. | This paper provides a review that summarizes several examples of the literature from 1980 to 2003, to illustrate the applications of stripping potentiometry for the determination and speciation of arsenic in several samples. A discussion on the main advantages of stripping potentiometry in comparison with other electro... | 18,969,843 |
Anion recognition through novel C-thiophenecalix[4]resorcinarene: PVC based sensor for chromate ions. | Novel ionophore, C-thiophenecalix[4]resorcinarene (I) has been synthesized and characterized by IR, NMR and C, H, N analysis. Poly(vinyl chloride) (PVC) based membranes of ionophore (I) using dibutylphthalate (DBP), dioctylphthalate (DOP), 1-chloronapthalene (CN), tris(2-ethylhexyl) phosphate (TEHP) and bis(2-ethylhexy... | 18,969,858 |
Extraction chromatographic method for the separation of actinides and lanthanides using EDHBA grafted AXAD-16 polymer. | A new extraction chromatographic method has been developed by grafting chloromethylated polymer support with 4-ethoxy-N,N-dihexylbutanamide (EDHBA), for the selective extraction of U(VI), Th(IV), La(III) and Nd(III) from highly acidic matrices. The developed grafted polymer has been characterized using (13)C-CPMAS NMR ... | 18,969,861 |
Fluorescence sensors for monosaccharides based on the 6-methylquinolinium nucleus and boronic acid moiety: potential application to ophthalmic diagnostics. | Continuous monitoring of glucose levels in human physiology is important for the long-term management of diabetes. New signaling methods/probes may provide an improved technology to monitor glucose and other physiologically important analytes. The glucose sensing probes, BMQBAs, fabricated using the 6-methylquinolinium... | 18,969,865 |
Strategies for solving matrix effects in the analysis of sulfathiazole in honey samples using three-way photochemically induced fluorescence data. | A widely employed compound for honey treatment, sulfathiazole (ST), was determined in commercial honey samples, employing a combination of photochemically induced fluorescence excitation-emission matrices (EEMs) and chemometric processing of the recorded second-order data. Parallel Factor Analysis (PARAFAC) and Self-We... | 18,969,872 |
Attempts to include uncorrected bias in the measurement uncertainty. | In ISO Guide it is strictly recommended to correct results for the recognised significant bias, but in special cases some analysts find out practical to omit the correction and to enlarge the expanded uncertainty for the uncorrected bias instead. In this paper, four alternatively used methods computing these modified e... | 18,969,876 |
Automatic flow procedure based on multicommutation exploiting liquid-liquid extraction for spectrophotometric lead determination in plant material. | A not expensive automatic flow system based on multicommutation and exploiting the liquid-liquid extraction methodology for the determination of lead in plant material is described. The spectrophotometric procedure for lead determination was based on the reaction with dithizone followed by extraction using an organic s... | 18,969,878 |
Determination of the hydroxyl radical by its adduct formation with phenol and liquid chromatography/electrochemical detection. | An HPLC-ECD method is described for the indirect determination of the hydroxyl (OH) radical. Fenton's reaction is used to produce OH, which simultaneously attacks phenols (phenol or pyrocatechol) to form the adducts, pyrocatechol or pyrogallic acid. Thus, [OH] quantification is based on the separation and detection of ... | 18,969,882 |
Modification of carbon ceramic electrode prepared with sol-gel technique by a thin film of chlorogenic acid: application to amperometric detection of NADH. | The carbon ceramic electrode prepared with sol-gel technique is modified by a thin film of chlorogenic acid (CGA). By immersing the carbon ceramic electrode in aqueous solution of chlorogenic acid at less than 2s a thin film of chlorogenic acid adsorbed strongly and irreversibly on the surface of electrode. The cyclic ... | 18,969,884 |
A new type of a spectrometric microtitration set up. | A spectrometric microtitrator was developed from a spectrometer with a microreaction chamber and a tri-colour light-emitting diode (LED) as the light source. A novel, vertical, optical geometry of the spectrometric microtitration chamber was introduced and tested. This novel geometry also required a new method for mixi... | 18,969,887 |
Dynamic analysis of aggregation of methylene blue with polarized optical waveguide spectroscopy. | Polarized optical waveguide (POW) spectroscopy permits analysis of the changing molecular state of methylene blue (MB), including aggregate order and orientation at the waveguide surface. Monomer or dimer, dissolved randomly in MB aqueous solution, tends to aggregate at the waveguide surface during air drying. Furtherm... | 18,969,913 |
Comparative study of pretreatment methods for the determination of metals in atmospheric aerosol by electrothermal atomic absorption spectrometry. | A comparative study of pretreatment methods for the determination of 10 elements (As, Cd, Pb, V, Ni, Mn, Cr, Cu, Fe, Al) in atmospheric aerosols by electrothermal atomic absorption spectrometry (ETAAS) was conducted. For the digestion of the particulates collected in filters, six methods were compared using a mixture o... | 18,969,931 |
Overview on the Gran and other linearisation methods applied in titrimetric analyses. | The paper provides some linearisation methods presented in modified (Gran I method), extended (pH-static titration) and generalised (Ni method) or corrected versions. Particularly, the modified Gran I method, based on the approximation ln(1+x) congruent withx/(1+x/2), enables (a) significant error inherent in the origi... | 18,969,938 |
Synchronous fluorescence and UV-vis spectrometric study of the competitive interaction of chlorpromazine hydrochloride and Neutral Red with DNA using chemometrics approaches. | In this study, we have shown with the use of UV-vis spectrophotometry and the constant wavelength synchronous fluorescence spectroscopy (CW-SFS) techniques that the pharmaceutical drug, chlorpromazine hydrochloride (CPZ), intercalates into the deoxyribonucleic acid (DNA) double helix by partial exchange with the Neutra... | 18,969,944 |
Simultaneous determination of trace arsenic, antimony, bismuth and selenium in biological samples by hydride generation-four-channel atomic fluorescence spectrometry. | A new and sample technique for the simultaneous determination of trace arsenic, antimony, bismuth and selenium in biologic samples by hydride generation-four-channel nondispersive atomic fluorescence spectrometry was development. The conditions of instrumentation and hydride generation of arsenic, antimony, bismuth and... | 18,969,948 |
The ion-pair formation between dodecylsulfate and ammine-complexes of copper(II), nickel(II), zinc(II), palladium(II) and platinum(II), and the extraction behavior of the ammine-complexes by using sodium dodecylsulfate. | A micellar solution of sodium dodecylsulfate (SDS) exhibits the property of being separated into two phases due to a temperature change or the addition of salts. The ammine-complexes of copper(II), nickel(II) and palladium(II) reacted with the dodecylsulfate anion to form the corresponding ion-pair, and were extracted ... | 18,969,960 |
Determination of methanol in o,o-dimethyldithiophosphoric acid (DMDTPA) of technical grade by UV/vis spectrophotometry and by HPLC. | Two procedures are proposed in this work for the determination of methanol impurities in o,o-dimethyldithiophosphoric acid (DMDTPA). To avoid possible interferences from the main component, DMDTPA was precipitated in the form of insoluble lead complex. Free Pb(II) ions were eliminated with sulfuric acid and methanol wa... | 18,969,971 |
Synthesis of cross-linked chitosan possessing N-methyl-d-glucamine moiety (CCTS-NMDG) for adsorption/concentration of boron in water samples and its accurate measurement by ICP-MS and ICP-AES. | A chitosan resin derivatized with N-methyl-d-glucamine (CCTS-NMDG) was synthesized by using a cross-linked chitosan (CCTS) as base material. The N-methyl-d-glucamine (NMDG) moiety was attached to the amino group of CCTS through the arm of chloromethyloxirane. The adsorption behavior of 59 elements on the synthesized re... | 18,969,973 |
Flow analysis techniques for phosphorus: an overview. | A bibliographical review on the implementation and the results obtained in the use of different flow analytical techniques for the determination of phosphorus is carried out. The sources, occurrence and importance of phosphorus together with several aspects regarding the analysis and terminology used in the determinati... | 18,969,995 |
Trace and ultratrace analysis methods for the determination of phosphorus by flow-injection techniques. | Trace (< or =1 mg/l or 30 microM) and ultratrace (< or =1 microg/l or 30 nM) analysis methods for phosphorus determination by flow-injection analysis are reviewed. Most of the methods cited in this review are fundamentally based on the reaction of orthophosphate with molybdate to form heteropoly acids, such as mo... | 18,969,996 |
Determination of dissolved reactive phosphorus (DRP) and dissolved organic phosphorus (DOP) in natural waters by the use of rapid sequenced reagent injection flow analysis. | A FI system for rapid sequential determination of dissolved reactive and organic phosphate is described. It utilizes on-line UV photo-oxidation for digestion of dissolved organic phosphate (DOP) with detection of the phosphate produced as phosphomolybdenum blue at 690 nm after reduction of phosphomolybdate with tin(II)... | 18,970,006 |
Glucose biosensors based on the immobilization of copper oxide and glucose oxidase within a carbon paste matrix. | The performance of amperometric glucose biosensors based on the dispersion of glucose oxidase (GOx) and copper oxide within a classical carbon (graphite) paste composite is reported in this work. Copper oxide promotes an excellent electrocatalytic activity towards the oxidation and reduction of hydrogen peroxide, allow... | 18,970,008 |
RETRACTED: Simultaneous flow-through determination of nitrites, nitrates and their mixtures in environmental and biological samples using spectrophotometry. | This article has been retracted at the request of the Editors-in-Chief. Please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). REASON: Considerable concern was raised about the research purportedly conducted at Sri Venkateswara University, India with the alleged involvement ... | 18,970,014 |
Solid phase extraction preconcentration of cobalt and nickel with 5,7-dichloroquinone-8-ol embedded styrene-ethylene glycol dimethacrylate polymer particles and determination by flame atomic absorption spectrometry (FAAS). | This article explores the synthesis of styrene-divinyl benzene (DVB)/ethylene glycol dimethacrylate (EGDMA) polymers embedded with quinoline-8-ol (Q) or its dihalo derivatives by thermal means in the presence and absence of 4-vinyl pyridine (VP). The above-synthesized polymers were found to enrich cobalt and nickel pre... | 18,970,015 |
On-site determination of polynuclear aromatic hydrocarbons in seawater by stir bar sorptive extraction (SBSE) and thermal desorption GC-MS. | The identification and quantification of semi-volatile contaminants dissolved in water is currently done in laboratory after a sampling step. This procedure is not satisfactory first because risks of samples contamination and analytes losses remain, in particular when these are present in ultra-trace concentrations, an... | 18,970,019 |
Determination of psilocybin in hallucinogenic mushrooms by reversed-phase liquid chromatography with fluorescence detection. | The determination of psilocybin was carried out by reversed-phase liquid chromatography (HPLC) with fluorescence (FL) detection. Psilocybin was labeled with 5-dimethylaminonaphthalene-1-[N-(2-aminoethyl)]sulfonamide (DNS-ED) at 60 degrees C for 4h in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) ... | 18,970,021 |
A highly selective mercury electrode based on a diamine donor ligand. | (H(2)NCHMeCH(2)NH(2))(H(2)O)(2)HgCl(2) (I) was synthesised, characterised and used for the fabrication of a potentiometric sensor for Hg(2+) metal ions. Membrane having I as electroactive material, sodium tetraphenyl borate (NaTPB) as an anion excluder, dibutylamine (DBA) as plasticizer in PVC matrix in the percentage ... | 18,970,023 |
Determination of trace elements in fly ash samples by FAAS after applying different digestion procedure. | The fly ash samples obtained from Kangal Power Plant were prepared for FAAS analysis by a new approach. The trace elements of the fly ash samples were leached with appropriate solvents under suitable conditions. The leaching method is known as an effective technique for substances dissolving very hard and refractory ma... | 18,970,026 |
Liquid-liquid-liquid phase microextraction of aromatic amines in water using crown ethers by high-performance liquid chromatography with monolithic column. | Liquid-liquid-liquid phase microextraction (LLLME) coupled with high-performance liquid chromatography (HPLC) for the analysis of some aromatic amines is described. These compounds were extracted from 4.0mL aqueous sample that adjusted to pH 13 with, NaOH-NaCl buffer solution (donor phase, P(1)) into an organic phase (... | 18,970,036 |
Flow-through optosensing of 1-naphthaleneacetic acid in water and apples by heavy atom induced-room temperature phosphorescence measurements. | A sensitive and selective phosphorimetric method for the determination of 1-naphthaleneacetic acid (1-NAA) based on a flow-injection system connected to a flow cell packed with a solid support and placed in the sample compartment of a conventional luminescence spectrometer is described. A non-ionic solid polymeric resi... | 18,970,041 |
Membrane electrodes for the determination of glutathione. | Four glutathione (GSH)-selective electrodes were developed with different techniques and in different polymeric matrices. Precipitation-based technique with bathophenanthroline-ferrous as cationic exchanger in polyvinyl chloride (PVC) matrix was used for sensor 1 fabrication. beta-Cyclodextrin (beta-CD)-based technique... | 18,970,048 |
Electrochemical identification of flavonoid dyes in solid work of art samples by abrasive voltammetry at paraffin-impregnated graphite electrodes. | An electrochemical method for identifying flavonoid-type dyes in microsamples from works of art is reported. Square wave voltammograms of natural insoluble dyestuffs based on flavonoid structure dragoon's blood, weld, old fustic, gamboge, Brazilwood and logwood (Campeche wood) attached to paraffin-impregnated graphite ... | 18,970,051 |
Determination of traces of Ni in Li(2)CO(3)/Na(2)CO(3) melts by graphite furnace atomic absorption spectrometry. | A graphite furnace atomic absorption method is described for the determination of traces of Ni in 52mole percent (mol.%) Li(2)CO(3) and 48mol.% Na(2)CO(3) melts after dissolution of the sample in dilute nitric acid. Maximum pyrolysis and optimum atomisation temperatures for the analyte were determined in the presence o... | 18,970,055 |
Homogeneous liquid-liquid extraction method for the selective separation and preconcentration of ultra trace molybdenum. | A new simple and efficient homogeneous liquid-liquid extraction method for the selective separation and preconcentration of molybdenyl ions was developed. alpha-Benzoin oxime (ABO) was investigated as a complexing ligand, and perfluorooctanoate ion (PFOA(-)) was applied as a phase-separator agent under strongly acidic ... | 18,970,071 |
A selective modified carbon paste electrode for determination of cyanide using tetra-3,4-pyridinoporphyrazinatocobalt(II). | A chemically modified carbon paste electrode with 3,4-tetra pyridinoporphirazinatocobalt(II) (Co(3,4 tppa) was applied to the determination of free cyanide ion. The electrode has a linear range between 1.5x10(-5)M and 1.0x10(-2)M with a Nernstian slope of 60+/-1.5mV/decade and its detection limit is 9x10(-6)M. The resp... | 18,970,074 |
A highly selective thallium(I) electrode based on a thia substituted macrocyclic ionophore. | A new highly Tl(I)-selective PVC membrane electrode based on tetrathia macrocycle 6,7: 14,15-dibenzo-5,8,13,16-tetraoxo-1,4,9,12-tetrathiacyclohexadecane [Bz(2)O(4)(16)aneS(4)] (I) as membrane carrier, o-nitrophenyloctyl ether (o-NPOE) as solvent mediator and potassium tetrakis(p-chlorophenyl)borate (KTpClPB) as lipoph... | 18,970,082 |
Dynamic coating for resolving rhodamine B adsorption to poly(dimethylsiloxane)/glass hybrid chip with laser-induced fluorescence detection. | In this paper a method was described about dynamic coating for resolving rhodamine B (RB) adsorption on a hybrid poly(dimethylsiloxane) (PDMS)/glass chip. The results showed that when the non-ionic surfactant Triton X-100 was higher than 0.5% (v/v) into the phosphate buffer, the adsorption of RB appeared. Besides, some... | 18,970,086 |
Sequential injection system with higher dimensional electrochemical sensor signals Part 2. Potentiometric e-tongue for the determination of alkaline ions. | An intelligent, automatic system based on an array of non-specific-response chemical sensors was developed. As a great amount of information is required for its correct modelling, we propose a system generating it itself. The sequential injection analysis (SIA) technique was chosen as it enables the processes of traini... | 18,970,109 |
Micro-focused ultrasonic solid-liquid extraction (muFUSLE) combined with HPLC and fluorescence detection for PAHs determination in sediments: optimization and linking with the analytical minimalism concept. | Analytical minimalism is a concept that deals with the optimization of all stages of an analytical procedure so that it becomes less time, cost, sample, reagent and energy consuming. The guide-lines provided in the USEPA extraction method 3550B recommend the use of focused ultrasound (FU), i.e., probe sonication, for t... | 18,970,118 |
Use of chemical modification and spectroscopic techniques to determine the binding and coordination of gadolinium(III) and neodymium(III) ions by alfalfa biomass. | Metal pollution in the aqueous environment has become an important issue in the past few decades leading to extensive research in the area of pollution remediation. Most of the recent research in this area has been in bioremediation including phytofiltration and phytoextraction. Although there has been a lot of researc... | 18,970,134 |
Comparison of ultrasound-assisted extraction and direct immersion solid-phase microextraction methods for the analysis of monoterpenoids in wine. | Ultrasound-assisted extraction (UAE) and direct immersion solid-phase microextraction (DI-SPME) were evaluated for the monoterpenic compounds determination in wine samples. The wine extracts obtained were analyzed by gas chromatography-mass spectrometry (GC-MS). The optimization of the variables affecting UAE and SPME ... | 18,970,146 |
Application of Metalfix Chelamine prior to the determination of noble metals by the inductively coupled plasma atomic emission spectrometry. | Metalfix Chelamine chelating resins of two different bead sizes (150-300 and 40-80mum) were examined and compared regarding their application for sorption of Au, Ir, Pd, Pt, Rh and Ru ions from medium of HCl, HNO(3) and mixtures of HCl and HNO(3). The quantitative enrichment of Au, Ir, Pd and Pt was established for the... | 18,970,149 |
Determination of total inorganic arsenic in water using on-line pre-concentration and hydride-generation atomic absorption spectrometry. | A rapid and sensitive method for the on-line separation and pre-concentration of inorganic arsenic in water samples is described. The analyte in the pentavalent oxidation state is reduced to its trivalent form with l-cysteine and the total inorganic arsenic is sorbed onto activated alumina in the acid form in a mini-co... | 18,970,151 |
Simple and highly predictive QSAR method: application to a series of (S)-N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-methoxybenzamides. | A simple quantitative structure-activity relationship (QSAR) method of analysis used to predict biological activity for congeneric series of compounds is reported. This method is based on the application of bilinear or multilinear partial least squares regression to a data set, which is a binary matrix representing the... | 18,970,153 |
Flow-injection spectrophotometric determination of methyldopa in pharmaceutical formulations. | A flow-injection spectrophotometric procedure is proposed for methyldopa determination in pharmaceutical preparations. The determination is based on formation of a yellow product (measured at 410nm) after complexation of methyldopa with molybdate. Under optimal conditions, Beer's law is obeyed in a concentration range ... | 18,970,162 |
Rapid fluorophosphate nerve agent detection with lanthanides. | We explore the detection of vapors of diisopropylfluorophosphate, a model compound for nerve agents such as Sarin, by means of photoluminescence quenching of filter paper impregnated with sensitized complexes of lanthanides, involving thenoyltrifluoroacetone and 1,10-phenanthroline as sensitizing ligands. We find that ... | 18,970,179 |
Sampling strategies for the analysis of glass fragments by LA-ICP-MS Part I. Micro-homogeneity study of glass and its application to the interpretation of forensic evidence. | The authors have previously reported the use of laser ablation ICP-MS as a powerful analytical tool for elemental analysis of glass. LA is a simpler, faster and less intrusive sample introduction method than the conventional solution ICP-MS. Due to the minute amount of material removed in LA ( approximately 300ng, 50mu... | 18,970,180 |
Gas chromatography positive chemical ionization and tandem mass spectrometry for the analysis of organic high explosives. | The characteristic ions or the parent ion resulting from ionization can be isolated in an ion trap and subjected to further fragmentation during a gas chromatography-tandem mass spectrometry (GC/MS/MS) experiment. This approach can improve the selectivity and sensitivity of explosive compounds over gas chromatography-m... | 18,970,185 |
Towards single-spot multianalyte molecular beacon biosensors. | The separate developments of microarray patterning of DNA oligonucleotides, and of DNA hairpins as sensitive probes for oligonucleotide identification in solution, have had a tremendous impact on basic biological research and clinical applications. Herein, we will discuss several successful efforts to develop oligonucl... | 18,970,192 |
Synthesis of polystyrene beads loaded with dual luminophors for self-referenced oxygen sensing. | Dispersion polymerization has been successfully applied to synthesize monodisperse polystyrene beads loaded with SiOEP and PtOEP for self-referenced oxygen sensing. The polystyrene beads became larger in size as the concentration of initiator was increased due to the reduction of primary particles precipitated from the... | 18,970,194 |
An efficient method for recovery of target ssDNA based on amino-modified silica-coated magnetic nanoparticles. | In this paper, an improved recovery method for target ssDNA using amino-modified silica-coated magnetic nanoparticles (ASMNPs) is reported. This method takes advantages of the amino-modified silica-coated magnetic nanoparticles prepared using water-in-oil microemulsion technique, which employs amino-modified silica as ... | 18,970,204 |
Sensitized extraction spectrophotometric determination of Hg(II) with dithizone after its flotation as ion-associate using iodide and ferroin. | This paper describes a simple and highly selective method for the separation, preconcentration and spectrophotometric determination of extremely low concentration of mercury. The method is based on the flotation of an ion-associate of HgI(4)(2-) and ferroin between aqueous and n-heptane interface at pH 5. The ion-assoc... | 18,970,205 |
Selective preconcentration of thorium in the presence of UO(2)(2+), Ce(3+) and La(3+) using Th(IV)-imprinted polymer. | We have prepared Th(IV) ion-imprinted polymers, which can be used for the selective preconcentration of Th(IV) ions, represented by uranium and lanthanides. N-methacryloyl-(l)-glutamic acid (MAGA) was chosen as the complexing monomer. In the first step, Th(IV) was complexed with MAGA and the Th(IV)-imprinted poly[ethyl... | 18,970,218 |
Quantitative detection of dye labelled DNA using surface enhanced resonance Raman scattering (SERRS) from silver nanoparticles. | The detection of dye labelled DNA by surface enhanced resonance Raman scattering (SERRS) is reported. The dye labels used are commercially available and have not previously been used as SERRS dyes. Detection limits using two excitation frequencies were determined for each label. This expands the range of labels which c... | 18,970,222 |
Determination of linear alkylbenzene sulfonates in water samples by liquid chromatography-UV detection and confirmation by liquid chromatography-mass spectrometry. | A high-performance liquid chromatographic (HPLC) method was developed for the separation and determination of individual (C(10)-C(13)) linear alkylbenzene sulfonates (LAS). New sets of conditions have been established for routine analysis of individual chemical forms of four LAS surfactants, i.e. C(10)-C(13) LAS. Under... | 18,970,226 |
Flow injection fluorimetric determination of chromium(VI) in electroplating baths by luminescence quenching of tris(2,2'-bipyridyl) ruthenium(II). | A sensitive and selective luminescence quenching method is developed and used for manual and flow injection analysis (FIA) of chromium(VI) by reaction with [Ru(bpy)(3)](2+). The emission peak of ruthenium(II) at 595 nm is linearly decreased as a function of Cr(VI) concentration. This permits determination of chromium(V... | 18,970,227 |
High throughput continuous titration based on a flow ratiometry controlled with feedback-based variable triangular waves and subsequent fixed triangular waves. | We propose a new approach for high-throughput continuous titration based on a flow ratiometry. The method was applied to potentiometric titrations of acids and bases. A base solution, the flow rate F(B) of which was varied in response to controller output voltage V(c), was merged with an acid solution under constant to... | 18,970,249 |
A method for the separation of beryllium from spectral interfering elements in inductively coupled plasma-atomic emission spectroscopic analysis. | A quick, simple and effective chromatographic method for the separation of beryllium from a wide range of elements is described. The elements selected comprise elements which can interfere with the determination of beryllium by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and elements which commonl... | 18,970,253 |
Direct determination of cadmium in urine by electrothermal atomic absorption spectrometry after in situ electrodeposition. | Determination of cadmium in urine by ETAAS suffers from severe interferences deteriorating the precision and accuracy of the analysis. Electrodeposition step prior to ETAAS allows to avoid interferences and makes cadmium determination possible even at ultratrace levels. The proposed procedures involve electrolytic depo... | 18,970,260 |
Studies on differential sensing of dopamine at the surface of chemically sensitized ormosil-modified electrodes. | We report herein the preparation of few chemically sensitized organically modified sol-gel glass (ormosil) films and sensing of dopamine at the surface of the modified electrodes derived from these films. The chemical sensitization in ormosil-modified electrodes is introduced by incorporating: (a) potassium ferricyanid... | 18,970,271 |
Electrochemical performances of C/Fe nanocomposite and its use for mediator-free glucose biosensor preparation. | C/Fe nanocomposite (CFN) was synthesized by a procedure similar to an exfoliation/adsorption process to intercalate Fe(3+) into graphite oxide (GO) layers and would be reduced in a H(2) atmosphere. The results of X-ray diffractometry (XRD) and transimission electron microscopy (TEM) show that the form of CFN is carbon ... | 18,970,278 |
Nanometer titanium dioxide immobilized on silica gel as sorbent for preconcentration of metal ions prior to their determination by inductively coupled plasma atomic emission spectrometry. | Nanometer titanium dioxide immobilized on silica gel (immobilized nanometer TiO(2)) was prepared by sol-gel method and characterized by using X-ray diffraction (XRD) and scanning electron microscope (SEM). The adsorptive potential of immobilized nanometer TiO(2) for the preconcentration of trace Cd, Cr, Cu and Mn was a... | 18,970,280 |
Identification of essential components of Houttuynia cordata by gas chromatography/mass spectrometry and the integrated chemometric approach. | Starting with Biller-Biemann's work [J.E. Biller, K. Biemann, Anal. Lett. 7 (1974) 515], various kinds of approaches have been proposed to extract GC/MS data to obtain pure components responses. In this paper, an integrated chemometric approach is proposed, which combine four sequential steps, data pretreatment, compon... | 18,970,292 |
GC-MS analysis of dichlobenil and its metabolites in groundwater. | We have developed a new method for the determination of the widely used herbicide 2,6-dichlorobenzonitrile (dichlobenil) and its major metabolites 2,6-dichlorobenzamide (BAM) and 2,6-dichlorobenzoic acid (2,6-DCBA) in groundwater samples. The procedure is based on solid phase extraction (SPE) combined with a derivatiza... | 18,970,297 |
A new approach for the sequential injection spectrophotometric determination of the total antioxidant activity. | A sequential injection system based on the ABTS (2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic-acid) methodology was developed. The proposed method, incorporating a mixing chamber in the side port of the selection valve, was evaluated to measure the total antioxidant activity of several beverages and foods. The AB... | 18,970,306 |
Coupling on-line of a dialyser with a flow-continuous system to separate Vitamin B(12) from milk. | The use of membranes for on-line separations in flow-through dialyser as a part of a flow system is extremely useful for automated samples preparation. In this paper a method to couple the dialysis and the UV detection on-line of Vitamin B(12) from milk is proposed. Firstly, the milk samples were pre-treated with trich... | 18,970,320 |
Determining salinity using a multimode fiber optic surface plasmon resonance dip-probe. | For the first time a fiber optic surface plasmon resonance sensor with demonstrated accuracy and precision of less than 200 ppm salinity is presented for calibration across a range of temperatures and salinities. Also shown is the potential for the sensor system to reach precisions of 10 ppm or less. Calibration models... | 18,970,350 |
Synthesis and characterization of a novel cross-linking complex of beta-cyclodextrin-o-vanillin furfuralhydrazone and highly selective spectrofluorimetric determination of trace gallium. | A novel host inclusion complex of cross-linking-polymeric-beta-cyclodextrin-o-vanillin furfuralhydrazone (beta-CDP-OVFH) was synthesized and characterized with IR and (1)H NMR spectra to confirm its structure. A highly selective and sensitive fluorescent determination of trace amounts of gallium was proposed based on t... | 18,970,359 |
Polarographic determination of sunscreen agents in cosmetic products in micellar media. | This paper introduces a simple, fast and reliable electroanalytical method for differential-pulse polarography based on electrochemical reduction at a dropping mercury electrode. The method was validated for the determination of 2-ethylhexyl-4-methoxycinnamate (EHMC) alone and in association with 4-methylbenzylidene ca... | 18,970,375 |
A method for DNA detection in a microchannel: fluid dynamics phenomena and optimization of microchannel structure. | A simple DNA diagnosis method using microfluidics has been developed which requires simple and straightforward procedures such as injection of sample and probe DNA solutions. This method takes advantage of the highly accurate control of fluids in microchannels, and is superior to DNA microarray diagnosis methods due to... | 18,970,378 |
Separation and determination of terbinafine and its four impurities of similar structure using simple RP-HPLC method. | A novel reversed-phase HPLC method for the simultaneous determination of active component terbinafine, its one impurity 1-methylaminomethylnaphtalene and three degradation products, beta-terbinafine, Z-terbinafine and 4-methyl-terbinafine occurring in pharmaceutical formulations after long-term stability tests, was dev... | 18,970,380 |
Preparation and layer-by-layer self-assembly of positively charged multiwall carbon nanotubes. | The report described a method of more stably dispersing oxidized carbon nanotubes (CNTs) by forming complex with polycation and the layer-by-layer self-assembly behavior of the complex with polyanion was studied. The properties of the self-assembled multilayer film containing carbon nanotubes were studied. Cyclic volta... | 18,970,386 |
UV-vis spectrophotometric method for the quantitation of all the components of Italian general denaturant and its application to check the conformity of alcohol samples. | A simple, fast and relatively inexpensive spectrophotometric method for the identification and the quantification of the individual components of the Italian general denaturant in alcohol samples is proposed. In particular, it is shown that bitrex (a quaternary ammonium salt), whose UV spectrum is completely masked by ... | 18,970,391 |
An EPR study on ancient and newly synthesised Egyptian blue. | Two sets of ancient Roman Egyptian blue (EB) samples and one set of EB samples synthesised in our lab, were analysed by EPR spectroscopy, a technique not commonly used in this field. The spectroscopic parameters obtained were used to attempt the discrimination of the provenance and of the manufacturing techniques of th... | 18,970,397 |
Screening of domperidone in wastewater by high performance liquid chromatography and solid phase extraction methods. | Domperidone is a dopamine D(2) receptor antagonist, which has been used as antiemetic agent in human beings. It has been found in wastewater released by some pharmaceutical industries leading to the contamination of surface and ground water. Therefore, a sensitive, inexpensive and reproducible HPLC-SPE method was devel... | 18,970,411 |
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