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In this work, an on-line system with vapor-phase generation (VPG) and Fourier transform infrared (FTIR) spectrometric detection has been developed as a direct and highly selective analytical technique for the assay of penicillamine (PA). Potassium iodate solution was injected into a reactor, heated at 75°C, containing PA. The CO generated under these conditions was transported by means of N 2...
We report a method for the quantitative analysis of human serum leptin, which is a protein hormone associated with obesity, using a nanoarray protein chip based on a single-molecule sandwich immunoassay. The nanoarray patterning of a biotin-probe with a spot diameter of 150nm on a self-assembled monolayer functionalized by MPTMS on a glass substrate was successfully accomplished using atomic force...
In this work, the use of 1 H NMR spectroscopy and statistical approach to the evaluation of biodiesel–diesel blends quality is described. Forty-six mixtures of oil–diesel, biodiesel–diesel, and oil–biodiesel–diesel were analyzed by 1 H NMR and such data were employed to design four predictive models. Thirty-six mixtures were used in the calibration set and the others in the validation...
A new approach for glucose determination in blood based on the spectroscopic properties of blood hemoglobin (Hb) is presented. The biosensor consists of a glucose oxidase (GOx) entrapped polyacrylamide (PAA) film placed in a flow cell. Blood is simply diluted with bidistilled water (150:1, v:v) and injected into the carrier solution. When reaching the PAA film, the blood glucose reacts with the GOx...
Antimony is a common contaminant at abandoned sites for non-ferrous ore mining and processing. Because of the possible risk of antimony by transfer to plants growing on contaminated sites, it is of importance to analyze antimony and its species in such biota. A method based on high performance liquid chromatographic separation and inductively coupled plasma mass spectrometric detection (HPLC–ICP-MS)...
Organic compounds in ambient particulate matter (PM) samples are used as tracers for PM source apportionment. These PM samples are collected using high volume samplers; one such sampler is an impactor in which polyurethane foam (PUF) and polypropylene foam (PPF) are used as the substrates. The polymer substrates have the advantage of limiting particle bounce artifacts during sampling; however these...
A plasticized poly (vinyl chloride) membrane electrode based on 1,3-bis(2-cyanobenzene)triazene (CBT) for highly selective determination of platinum(II) (in PtCl 42− form) is developed. The electrode showed a good Nernstian response (29.8±0.3mVdecade −1 ) over a wide concentration range (1.0×10 −6 to 1.0×10 −2 molL −1 ). The limit of detection was 5.0×10...
A new method is developed for the catalytic oxidation of ascorbic acid at graphite zeolite-modified electrode, doped with copper(II) (Cu 2+ A/ZCME). Copper(II) exchanged in zeolite type A acts as catalyst to oxidize ascorbic acid. The modified electrode lowered the overpotential of the reaction by ∼400mV. First, the electrochemical behavior of copper(II), incorporated in the zeolite type A...
Although colorless ionic liquids (ILs) are most desirable, as synthesized they frequently bear color, despite appearing pure by most analytical techniques. It leads to some uncertainties and limits for the fundamental research and applications of ILs, such as spectroscopy. Using 1-butyl-3-methylimidazolium bromide (BMIMBr), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF 4 ) and 1-hexyl-3-methylimidazolium...
The principal components, isoflavonoids and astragalosides, in the extract of Radix Astragali were detected by a high-performance liquid chromatography couple to electrospray ionization ion trap multiple-stage tandem mass spectrometry (HPLC-ESI-IT-MS n ) method. By comparing the retention time (t R ) of HPLC, the ESI-MS n data and the structures of analyzed compounds with the...
A new methodology for the in-line preconcentration, clean-up and speciation of mercury by use of an anion-exchange membrane is proposed. The speciation of mercury is based on retention of its tetrachloro complex onto the membrane while organic mercury flows freely through it. A multisyringe is used as a liquid driver and a cold vapour atomic fluorescence detector is employed to ensure a high sensitivity...
ATP determination is of great importance since this compound is involved in a number of vital biological processes. To monitor ATP concentration levels, we have developed a microbiosensor based on cylindrical platinum microelectrode, covered with a layer of poly-m-phenylendiamine (PPD), and layer of co-immobilised glucose oxidase and hexokinase. Conditions for biosensor measurement of ATP (pH, Mg...
The combination of headspace–solid phase microextraction (HS–SPME) and gas chromatography–inductively coupled plasma mass spectrometry (GC–ICPMS) was evaluated for the determination of volatile selenium metabolites in normal urine samples, i.e. without selenium supplementation. HS–SPME operating conditions were optimised and a sampling time of 10min was found to be suitable for simultaneous extraction...
Research into the analysis and monitoring of steroidal estrogens has grown significantly over the last decade, resulting in the emergence of a range of applicable techniques. In this study, three popular techniques, gas chromatography–mass spectrometry (GC–MS), gas chromatography–tandem mass spectrometry (GC–MS–MS) and liquid chromatography–tandem mass spectrometry (LC–MS–MS) for the analysis of three...
Quantum dots (QDs) have been used as a new class of bioprobes in medical imaging in recent years. The study of interaction between QDs and biomacromolecules is important for interpreting biological data. In this work, Rayleigh light scattering (RLS) was employed to investigate the nonspecific interaction between mercaptoacetic acid modified CdSe/ZnS quantum dots (MAA–QDs) and human immunoglobulin...
Based on the principle of liquid core waveguide, a novel microfluidic device with micro-scale detection window capable of sensing flashlight emitted from rapid 1,1′-oxalyldi-4-methylimidazole (OD4MI) chemiluminescence (CL) reaction was fabricated. Light emitted from OD4MI CL reaction occurring in the micro-dimensional pentagonal detection window (length of each line segment: 900.0μm, depth: 50.0μm)...
Aristolochic acid I (AA I), a major component of the carcinogenic plant extract aristolochic acid (AA), is known to be nephrotoxic, carcinogenic and mutagenic. A simple, rapid and sensitive high-performance liquid chromatography–diode array detection–fluorescence detection (HPLC–DAD–FLD) method was developed and validated for the analysis of AA I and its metabolites in cell culture medium for the...
Carbon nanotube (CNT) electrodes in combination with ionic liquid (IL) electrolytes are potentially important for energy storage systems. We report electrochemical investigation of such a system involving a paper-electrode of multi-wall CNT (MWCNT) in the IL of 1-ethyl-3-methyl imidazolium ethylsulfate (EMIM-EtSO 4 ). Our study concentrates on the analytical aspects of cyclic voltammetry (CV)...
An improved single step microwave digestion procedure is described for providing the fast and easy exhaustive mineralisation of biological samples concomitantly with the quantitative conversion of any type of selenium compounds into Se(IV). In such a way, digested samples are directly suitable for the subsequent Se analysis at trace and ultratrace levels by both spectrometric methods such as HG-ICP-MS...
With the given special structures, the CD bonded stationary phases are expected to have complementary retention properties with conventional C18 stationary phase, which will be helpful to enhance the polar selectivity in RP mode separation. In this work, two β-cyclodextrin (β-CD) bonded stationary phases for reversed-phase HPLC, including 1, 12-dodecyldiol linked β-CD stationary phase (CD1) and olio...
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