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A simple and rapid method for the determination of LiCF 3 SO 3 and γ-LiAlO 2 in composite PEO (poly(ethylene)oxide)-based polymer electrolytes, both in mixtures and thin films, is described. The method is based on the dissolution of LiCF 3 SO 3 in anhydrous ethanol at room temperature and subsequently dissolution of PEO in water for the separation of γ-LiAlO...
A sensitive and rapid method for the determination of lanthanum, europium and ytterbium by inductively coupled plasma atomic emission spectrometry (ICP-AES) after solid-liquid extraction with microcrystalline naphthalene was developed. Analytes could be quantitatively adsorbed on tribromoarsenazo-cetylpyridinium bromide-naphthalene (TBA-CPB-naphthalene) packed in a column and determined by ICP-AES...
Derivative spectrophotometry (DS) was applied to determination of flavonols and a flavon in two-compound mixtures by means of 'zero-crossing' technique. Selected mixtures were, quercetin-kaempferol, quercetin-myricetin and quercetin-luteolin. The developed method was used as a complementary technique to a HPLC system, which does not separate quercetin and luteolin.
A simple flow injection on-line dilution procedure with detection by inductively coupled plasma mass spectrometry (ICP-MS) was developed for the determination of copper, zinc, arsenic, lead, selenium, nickel and molybdenum in human urine. Matrix effects were minimized by employing a dilution factor of 16.5 with on-line standard addition, and 103 Rh was used as internal standard to...
The interaction of histone with nucleic acids was characterized by light-scattering measurement using a common spectrofluorometer. Thereby, a sensitive and convenient method for the determination of nucleic acids was established. At pH 4.5-6.5, the interaction of histone with nucleic acids resulted in considerable light-scattering , and four characteristic peaks at 298, 450, 503, and 551 nm were observed...
The laccase activity, in the presence of ferulic acid as substrate, was tested with high performance liquid chromatography (HPLC). The two products initially formed were identified by HPLC-mass spectrometry and HPLC-diode array as trans-5-[(E)-2-carboxyvinyl]-2-(4-hydroxy-3-methoxy-phenyl)-7-methoxy-2,3-di hydrobenzofuran-3-carboxylic acid and (Z)-β-{4-[(E)-2-carboxyvinyl]-2-methoxyphenoxy}-4-hydroxy-3-methoxy...
Quantitative analysis of metallothioneins (MTs) by the modified Brdicka procedure is based on the evaluation of the catalytic hydrogen signal (Cat). The effect of the basic physico-chemical parameters, the temperature and the depolarizer concentration (Co(NH 3 ) 6 Cl 3 ), on the Cat signal height and the respective calibration straight lines was studied by means of the differential...
A new simple and rapid FI method for the accurate and precise spectrophotometric determination of ascorbic acid (AsA) in pharmaceutical formulations is reported. The method is based on the reduction of Fe(III) to Fe(II) by the analyte, and the subsequent reaction of the produced Fe(II) with 2,2'-dipyridyl-2-pyridylhydrazone (DPPH) in acidic medium (pH ca. 2.5) to form a colored complex (λ m ...
A spectrofluorimetric method has been developed for the determination of trace Cu(II) in real samples with 4,5-dihydroxy-l,3-benzenedisulfonic acid (Tiron) as a fluorimetric reporter. Tiron is very soluble in water and is a good fluorimetric reagent. However, as Tiron was complexed with Cu(II), the fluorescence intensity decreased proportionally to the concentration of Cu(II) by a static quenching...
A gold(I) organic complex in the perchlorate form was incorporated in plasticized poly(vinyl chloride) (PVC) membranes and the potentiometric response towards perchlorate (primary ion) and permanganate (interfering ion) was studied. Membranes with 2:1 and 1:2 (w/w) plasticizer to PVC ratio were selected for the determination of primary and interfering ions, respectively. In the selected flow injection...
The fabrication and performance of a reticulated vitreous carbon (RVC)-based tyrosinase flow-through electrode, in which the enzyme was covalently immobilized, is reported. The bioelectrode was tested as an amperometric detector for phenolic compounds. Variables affecting the construction of the enzyme flow-through electrode such as the RVC chemical pretreatment procedure, the enzyme immobilization...
A precise, accurate automatic preconcentration method for the determination of total arsenic at the ng g -1 level in wheat flour is proposed. The sensitivity of the method can be increased by a factor of 20 by precipitating As(V) from 10 ml of digested sample using a weakly acid silver solution. The Ag 3 AsO 4 precipitate is dissolved with 0.5 ml of 6 M ammonia and the...
A chlorphenamine-imprinted polymer was prepared in this study. Chromatographic analysis showed that the retentivity and selectivity of the imprinted polymer were greatly strengthened through molecular imprinting. As a consequence, chlorphenamine could be easily separated from diphenhydramine. Ionic interaction was proved to be the main power for the imprinted polymer to bind chlorphenamine. The strong...
Simultaneous analysis of multicomponent polycyclic aromatic hydrocarbons in mixture of micellar solution (CTAB) has been investigated. A simple synchronous fluorimetric method has been used, which does not require pretreatment of data, solving of large amount of data and large amount of solution preparation for internal calibration, thus making the analysis simple and fast. The method is fairly successful...
A new analytical method for the determination of ascorbic acid by the perturbation caused by different amounts of ascorbic acid on the BZ oscillating chemical system involving the Ce(IV)-catalyzed reaction between potassium bromate and malonic acid in a acidic medium is proposed. The method relies on the linear relationship between the change in the oscillation amplitude of the chemical system and...
A simple, sensitive, rapid and reliable method has been developed for spectrophotometric determinations of As(III) in the presence of As(V) based on its inhibition effect on the redox reaction between bromate and hydrochloric acid. The decolorization of methyl orange by the reaction products was used to monitor the reaction spectrophotometrically at 525 nm. The method allows the determination of arsenic...
A very simple, ultra-sensitive and fairly selective non-extractive spectrophotometric method for the determination of trace amounts of lead with 2,5-dimercapto-1,3,4-thiadiazole (DMTD) has been developed. DMTD reacts in slightly acidic (0.0015-0.01 M HCl) aquatic media with lead(II) to give a greenish-yellow chelate, which has an absorption maximum at 375 nm. The reaction is instantaneous and absorbance...
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