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1.
Eight azo dyes containing the 4,5-diphenylimidazole group have been synthesized, and their potential for determinations of metals has been studied spectrophotometrically. Of these reagents, the pyridylazo and quinolylazo derivatives are suitable as chromogenic reagents, the best being 2-(quinolylazo)-4,5-diphenylimidazole (QAI), which reacts with several metal ions. The copper and mercury complexes of QAI show molar absorptivities of the order of 80 000 l mol?1 cm?1. 相似文献
2.
Mouayed Q. Al-Abachi E. S. Salih M. S. Salem 《Fresenius' Journal of Analytical Chemistry》1990,337(4):408-411
Summary The oxidative coupling reaction of promethazine · HCl with primary aromatic amines was applied to the determination of seven pharmaceutical sulphonamides. A mixture of an acidic solution (3.5% acetic acid) of the sulphonamide and the chromogenic reagent was treated with hypochloriteion. The wavelength of maximum absorption is 610 nm, the molar absorptivities range from 1.57×104 to 1.89×104 l mole–1 cm–1 and Sandell sensitivities range from 0.00972 to 0.0136 g cm–2. A linear correlation was found between absorbance at max and concentration. The procedures developed for bulk sulpha drugs and some of their pharmaceutical preparations are rapid, accurate, precise and comparable to the Bratton-Marshall procedure. 相似文献
3.
Specific polyclonal-based immunoassays for sulfathiazole 总被引:4,自引:0,他引:4
Pastor-Navarro N García-Bover C Maquieira A Puchades R 《Analytical and bioanalytical chemistry》2004,379(7-8):1088-1099
A highly sensitive and specific enzyme-linked immunosorbent assay has been developed for detection of sulfathiazole (STZ, 4-amino-N-thiazol-2-yl-benzenesulfonamide). A set of haptens was synthesized in order to produce polyclonal antibodies against sulfonamides. Two ELISA formats (antibody-coated and conjugate-coated) were also investigated using all the serum/coating conjugate combinations that showed specific recognition. The developed ELISA succeeded in detection of STZ at concentrations as low as 0.03 ng mL–1 over a measurable range of 0.12–6.71 ng mL–1. Selectivity studies have demonstrated that other sulfonamides do not interfere significantly (<10%) with analysis of STZ by this immunochemical technique. Analysis of spiked bee honey samples by the developed ELISA method showed recoveries were good. The selectivity and sensitivity (IC50=1.6 ng mL–1) make it a suitable screening method for determination of low levels of STZ in food samples. 相似文献
4.
M. E. Moustafa E. H. EL-Mossalamy A. S. Amin 《Monatshefte für Chemie / Chemical Monthly》1995,126(8-9):901-908
Summary Four azo compounds based on 5-aminoindazole have been synthesized and characterized by elemental analysis as well as different spectroscopic techniques. The potentiality of the prepared compounds as new chromophoric reagents for the spectrophotometric determination of VO
2
+
was studied by extensive investigation of optimum conditions favouring the formation of the coloured complexes. The effect of interfering ions on the determination of VO
2
+
was investigated.Beer's law is obeyed in the concentration range of 1.0–12 µg/ml. The detection limits are 0.8, 0.9, 0.7, and 1.1 µg/ml using reagent1a,1b,1c, and1d, respectively. The standard deviations of the proposed method are 0.098, 0.111, 0.089, and 0.078. The molar absorptivities are 5.8, 6.7, 6.1, and 8.2×103l·mol–1·cm–1 for1a–d, respectively, whereasSandell sensitivities are found to be 0.0187, 0.0163, 0.0174, and 0.0146 µg·cm–2 using the same reagents. The ability of using these reagents as metallochromic reagents in complexon III titrations was also studied.
Synthese und Leistungsfähigkeit von 5-(Hydroxyphenylazo)-indazolen als neue Reagentien zur Bestimmung von Vanadium
Zusammenfassung Vier von 5-Aminoindazol abgeleitete Azoverbindungen wurden synthetisiert und mittels Elementaranalyse sowie mit Hilfe verschiedener spektroskopischer Techniken charakterisiert. Die Einsatzmöglichkeiten der Verbindungen als Reagentien zur spektrophotometrischen Bestimmung von VO 2 + wurde durch ausführliche Untersuchungen zur Ermittlung der optimalen Bedingungen für die Ausbildung der gefärbten Komplexe ausgetestet. Der Einfluß von Fremdionen auf die Ergebnisse wurde ebenfalls untersucht. DasBeer'sche Gesetz wird im Konzentrationsbereich von 1.0–12µg/ml befolgt. Die Nachweisgrenzen liegen bei 0.8, 0.9, 0.7 und 1.1 µg/ml für die Reagentien1a–d. Die entsprechenden Standardabweichungen betragen 0.098, 0.111, 0.089 und 0.078. Die Komplexe zeigen molare Extinktionen von 5.8, 6.7, 6.1 und 8.2×103l·mol–1·cm–1 und Empfindlichkeiten nachSandell von 0.0187, 0.0163, 0.0174 und 0.0146 für die jeweiligen Verbindungen1a–d. Die Verwendungsmöglichkeit der neuen Verbindungen als metallochrome Reagentien bei Titrationen mit Komplexon III war ebenfalls Gegenstand der Untersuchungen.相似文献
5.
The iodine quenching effect on the fluorescence of a binaphthyl-based amphiphile, C8BNC6N, was used for monitoring the Landolt-type reaction between nitrite, iodide, and thiosulfate. Due to the possibility of iodine detection in the 10–8–10–7
M range, and to the effective concentration of anionic reagents on the surface of cationic aggregates, the indicator reaction can be monitored using reagents at concentration levels as low as 10–7
M. To optimize the analytical system, the effect of pH and reagent concentrations on the rate of indicator reaction were studied. The influence of the matrix of water samples and effect of side-reactions increasing the value of a blank test were examined. A procedure for nitrite determination in water was developed, using the diazo reaction for selective nitrite removal to provide a reference solution, which avoided possible effects of the matrix components. The usefulness of this method was tested by determining trace amounts of nitrite in water samples. The procedure allows determination of nitrite down to 5 ng/ml (detection limit about 2ng/ml) with r.s.d. of 10% in the 20–250 ng/ml range. 相似文献
6.
Masamichi Furukawa 《Analytica chimica acta》1982,140(1):281-289
2-(2-ThiazolyIazo)-5-dimethylaminobenzoic acid (TAMB) and 2-(2-benzothiazolylazo)-5-dimethylaminobenzoic acid (BTAMB) have been synthesized, and their potential for determinations of metals has been studied spectrophotometrically. Both are extremely sensitive chromogenic reagents for the determination of nickel. Molar absorptivities in aqueous methanol are 0.95 × 105 (TAMB) and 1.2 × 105 (BTAMB). In aqueous methanol, at apparent pH 5–9.5, the system conforms to Beer's law for 0.05–0.5 ppm nickel; Cu, Cr, Co, Pd and Fe interfere, but they can easily be masked. 相似文献
7.
Biphenyl- and terphenyl-based recyclable trivalent iodine reagents, such as 4-bromo-4′-(diacetoxyiodo)biphenyl, 4,4′-bis(diacetoxyiodo)biphenyl, 1,4-bis[4-(diacetoxyiodo)phenyl]benzene, 4-bromo-4′-[(hydroxy)(tosyloxy)iodo]biphenyl, 4,4′-bis[(hydroxy)(tosyloxy)iodo]biphenyl, were simply prepared and their reactivities for the oxidative rearrangement of ketones to esters, TEMPO-mediated oxidation of alcohols to aldehydes or ketones, oxidative dealkylation of N-alkylsulfonamides to sulfonamides, and α-tosyloxylation of ketones were compared with p-(diacetoxyiodo)toluene and p-[(hydroxy)(tosyloxy)iodo]toluene to show the same reactivities and, moreover, the biphenyl- and terphenyl-based iodoarenes formed were recovered by simple filtration of the reaction mixture in every reaction. Thus, these biphenyl- and terphenyl-based trivalent iodine reagents can be used as the recyclable reagents. 相似文献
8.
Acetylacetone-formaldehyde reagent for the spectrophotometric determination of some sulfa drugs in pure and dosage forms 总被引:1,自引:0,他引:1
A new simple and sensitive spectrophotometric procedure for the determination of sulfacetamide sodium (I), sulfadiazine (II), sulfadimidine (III) and sulfathiazole (IV) is based on the reaction of the drug with acetylacetone-formaldehyde reagent to give a yellow product having max at 400 nm. Optimization of the reaction conditions has been investigated. A linear correlation was obtained between absorbance at max and the concentration. The Beer's law limits of I, II, III and IV are 4–80, 4–72, 4–60 and 4–80 g/ml, respectively. For more accurate results, Ringbom optimum concentration ranges were evaluated to be 6–76, 8–66, 6–56 and 8–75 g/ml for I, II, III and IV, respectively. The molar absorptivities and Sandell sensitivities for all sulfa drugs under consideration were evaluated. Relative standard deviations of 0.98, 1.07, 0.86 and 0.79% were obtained for I, II, III and IV, respectively. The method has been compared to the official method and found to be simple, accurate (t-test) and reproducible (F-test). The developed procedures were applied for bulk sulfa drugs and some of their dosage forms without interferences from additive and common prescribed drugs. 相似文献
9.
Multiple-component determinations present difficulties which cannot be resolved mathematically when there is severe spectral overlap, as in the determination of rare-earth elements with chromogenic reagents. The interdependence of absorptivities is greatly decreased when absorbance data from procedures based on several chromogenic reagents are used together in the calculations of calibration factors and concentrations. Various features of the method are discussed. 相似文献
10.
A simple, rapid and sensitive spectrophotometric method is described for the quantitative determination ofN-substituted phenothiazines. The method depends on the formation of a stable phenothiazine free radical cation by the use ofN-bromophthalimide as oxidising agent in a strong acid medium (methanol/ sulphuric acid 1 1 v/v). The produced red or violet color possesses absorption maximum range from 500 to 530 nm. A linear relationship exists between the absorbance at (max) and concentration in the range 5 to 40 g ml–1 with apparent molar absorptivities range from 6 × 103 to 12 × 1031 mol–1 cm–1. The color is developed instantaneously for all the studied phenothiazines except for thioproperazine mesylate, trifluoperazine dihydrochloride and prochlorperazine mesylate that require 25, 15 and 25 min, respectively, for complete reaction. The developed colors are stable over 24 h. The average % recovery is 99.85±0.61 to 100.28±0.95. The method was applied successfully to the microdetermination of chlorpromazine HCl, promethazine HCl, pericyazine, thioproperazine mesylate, perphenazine, prochlorperazine mesylate, trimeprazine tartrate and trifluoperazine 2HCl either in pure form or incorporated in their pharmaceutical preparations. The results of analysis are in good agreement with those of the official B.P. 1988 and USP XXII. 相似文献
11.
Nataly V. Semenova Elena I. Morosanova Igor V. Pletnev Irina M. Maksimova Yuri A. Zolotov 《Mikrochimica acta》1995,119(1-2):81-93
The new approach to enhancing the selectivity of sorption separation of metal ions was suggested. The approach is based on using mixed sorbents, which may be obtained, e.g. by simultaneous immobilization of complexing reagents on silica gel and reverse-phase silica gel (C16, Ph). The methods are developed for the simultaneous determination of two (Co-Fe, Co-Zn, Al-Mn) or three (Al, Mn and Fe) elements in the concentration range 2.10–6–7.10–4
M with the performance of 21–36 samples per hour. 相似文献
12.
The molar absorptivities of lithium picrate and of sodium picrate have been measured as a function of salt concentration (in the 0.1–1 mmol-dm–3 concentration range) in 2-propanol at 25°C. Values of the molar absorptivities of the free picrate ion i, of the ion pair p, and of the ion pair association constant Ka have been calculated for each salt. The Ka values for these two salts in this solvent calculated from spectrophotometric measurements were found to be the same within experimental uncertainty as the values of Ka calculated from conductance measurements. 相似文献
13.
Extended studies by e.p.r. and electronic spectroscopy on the effect of different non-polar solvents, temperature and disulfide concentration on the spectral properties of bis(dithiophosphato)copper(II), Cu[(RO)2PS2]2, complexes [R = Me, Et and i-Pr] are reported. The molar absorptivity and e.p.r. intensity are very sensitive to the shape and size of the remote ligand substituents and increase in the order: Me < Et < i-Pr. The nature of the solvent and time after dissolution are also important regarding the magnitude of the e.p.r. intensity and molar absorptivity which, 1 h after dissolution, do not follow Beer's law. The molar absorptivities obtained at a given CuII(R2–dtp)2 concentration increase in the solvent order: n-hexane < n-heptane < CCl4 < PhMe < PhH < CHCl3. Twenty-four hours after dissolution the same samples exhibit: (i) linearity between absorbance and concentration of CuII(R2–dtp)2; (ii) a significant increase in molar absorptivity which is not equal for all the complexes studied and follows the same substituent and solvent orders. Beer's law is satisfied above 5 × 10–4 M for [(RO)2PS2]2Cu (R = Et, i-Pr) and above 3 × 10–3 M for [(MeO)2PS2]Cu. A significant additional increase, ca. 30–40%, of molar absorptivity, is obtained by increasing the solution temperature from 20 to 50 °C. The molar absorbtivity remains unchanged during 2–3 days after reducing the temperature. Further increase of molecular absorbtivity appears after addition of the corresponding disulfide of dithiophosphate [(RO2)PS2–S2P(RO)2] to CuII[(RO)2PS2]2. The molar absorptivity of Cu[(i-PrO)2PS2]2 increases from 4.8 × 103 cm–1 M–1, 1 h after dissolving the complex up to 2 × 104 cm–1 M–1 after addition of the corresponding disulfide. The observed effects are explained on the basis of a self-redox reaction taking place in this type of sulfur containing copper(II) complexes. 相似文献
14.
Dr. Sergiy V. Zasukha Prof. Dr. Vadim M. Timoshenko Prof. Dr. Andrey A. Tolmachev Valentyna O. Pivnytska Oleksii Gavrylenko Dr. Serhii Zhersh Prof. Dr. Yuriy Shermolovich Dr. Oleksandr O. Grygorenko 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(28):6928-6940
Two novel solid reagents—1-sulfonimidoyl- and 1-sulfamimidoyl-3-methylimidazolium derivatives—for the synthesis of sulfonimidamides and imidosulfuric diamides, respectively, were developed. It is shown that these reagents are very effective in substitution reactions with various N- and O-nucleophiles; therefore, they significantly extend the accessibility to the chemical space covered by organosulfur(VI) compounds with S=N bonds. In addition, previously unknown imidosulfuric diamides with free imino nitrogen groups were prepared, and their physical and chemical properties were characterized (including molecular geometry, pKa, Log P, microsomal stability, and reactivity towards typical electrophiles). Similar to other organosulfur(VI) derivatives with S=N bonds, these compounds can be considered as promising bioisosteres of amides, ureas, or sulfonamides. 相似文献
15.
Three highly sensitive spectrophotometric methods for the determination of platinum(IV) have been developed, based on its colour reactions with molybdate and basic dyes (BD) in aqueous solution in the presence of poly(vinyl alcohol). Platinum(IV) reacts with molybdate and BD to form ion — association complexes of composition (BD)2[Pt (MoO4)3]. The molar absorptivities are between 6.83 × 105 and 9.51 × 105 dm3mol–1cm–1, the highest value being found with nile blue. Suitable conditions for the reactions and the effects of foreign ions were investigated. The methods can be applied to the spectrophotometric determination of trace amounts of platinum(IV) in some catalysts and ores. 相似文献
16.
A highly sensitive extractive spectrophotometric method for the determination of U(VI) using octadecyldithiocarbamate (ODDTC) has been developed. The efficiency of ODDTC as a chelating agent is compared with that of hexadecyl, tetradecyl and dodecyl dithiocarbamates. U(VI) reacts with these dithiocarbamates in ethanol to form reddish-brown water-insoluble chelates capable of being extracted into CHCl3. The molar absorptivities range from 1.16·10 to 4.91·104l·mol–1·cm–1, the highest value being found for ODDTC. Suitable conditions for the extraction and the effect of foreign ions were investigated. The method can be used for the determination of trace amounts of U(VI) in water and sand. The results are comparable to ICP-AES method. 相似文献
17.
A rapid and sensitive method for the photometric determination of trace amounts of neptunium and plutonium from their mixtures is described. Np(IV) is selectively extracted from about 1 M HNO3 medium with TTA in xylene retaining Pu in the nonextractable trivalent state in the aq. phase with ferrous sulfamate. Plutonium in the aqueous phase is subsequently oxidized with NaNO2 to the highly extractable tetravalent state and extracted with TTA. Np(IV) as well as Pu(IV) thus extracted are finally estimated in the organic phase itself spectrophotometrically employing xylenol orange as the chromogenic reagent. Their molar absorptivities are in the 5 × 104 range. Beer's law is valid up to 2.4 ppm Np and 3.5 ppm Pu. The color of the solutions is stable for at least 48 hr. The method tolerates large excess of several common contaminants encountered during spent fuel reprocessing. Cerium(IV) and phosphoric acid, however, interfere with the final estimation. 相似文献
18.
Hexamethylphosphoramide (HMPA) adducts of the type Ph3PbX·HMPA (X=Cl, Br, I, and NCS), Ph2PbX2·2HMPA (X=Cl, Br, and I), and Ph2PbX2·HMPA (X=Br and I), have been prepared and characterized by infrared, Raman, mass, and 31P nmr spectroscopy. Molecular weight and infrared solution data show that Ph3PbX·HMPA adducts dissociate in benzene, the degree of dissociation being NCS«Cl<Br<I. The thiocyanate adducts Ph3PbNCS·HMPA and Ph2Pb(NCS)2·2HMPA have v(CN) and v(CS) frequencies in the solid state, and v(CN) frequencies and absorptivities in benzene solution consistent with N-bonded thiocyanate in the solid state and in benzene solution. Vibrational frequencies are reported in the range 260 to 80 cm−1 and assignments are made for v(Pb-X), v(Pb-O0, and v(Pb-NCS) modes. The 1:1 adducts Ph3PbX·HMPA are monomeric and trigonal bipyramidal, whereas the 1:2 adducts Ph2PbX2·2HMPA are monomeric and cis-octahedral and the Ph2PbX2·HMPA appear to be halogen bridged polymers with lead six-coordinate. Coordination of HMPA causes a small upfield change in 31P chemnical shift values, and 2J(Pb-P) values vary with X in the order: NCS>I-Br>Cl for Ph3PbX·HMPA adducts. Corresponding tin and lead adducts are compared with respect to mode of adduct formation. 相似文献
19.
Flow cytometric immunoassay for sulfonamides in raw milk 总被引:2,自引:0,他引:2
de Keizer W Bienenmann-Ploum ME Bergwerff AA Haasnoot W 《Analytica chimica acta》2008,620(1-2):142-149
Sulfonamide antibiotics are applied in veterinary medicine for the treatment of microbial infections. For the detection of residues of sulfonamides in milk, a multi-sulfonamide flow cytometric immunoassay (FCI) was developed using the Luminex MultiAnalyte Profiling (xMAP) technology. In this automated FCI, a previously developed biotinylated multi-sulfonamide mutant antibody (M.3.4) was applied in combination with fluorescent beads, directly coated with a sulfathiazole derivative, and streptavidin–phycoerythrin (SAPE) for the detection. With this FCI, at least 11 different sulfonamides could be detected (more than 50% inhibition at the 100 ng mL−1 level) and, after an incubation of 1 h, measurements were rapid (10 s per sample). For the application with raw milk, a 96-well microplate-based filtration step was included into the protocol to remove disturbing milk fat particles. Because of differences in sensitivity towards different sulfonamides, the FCI was considered and validated as a qualitative screening assay. For sulfadoxine, the most applied sulfonamide in Dutch dairy cattle, the detection capability (CCβ) was <50 μg L−1 and this level seems feasible for five other sulfonamides. For sulfadiazine, the CCβ was <200 μg L−1 and this level seems feasible for four other sulfonamides. A major advantage of the applied xMAP-technology, with its 100 different color-coded bead sets, is the possibility to develop multiplex immunoassays for the simultaneous detection of several antibiotics. 相似文献
20.
Mohamed Tarek Mohamed Zaki Nabil Hafez A. Y. El-Sayed 《Monatshefte für Chemie / Chemical Monthly》1992,123(6-7):477-486
The complexation reactions of cerium(III and IV) with 9-phenyl-2,3,7-trihydroxy-6-fluorone (H3
PF) have been studied in the presence and absence of some surfactants and protective colloids. Maximum enhancement of the chelate absorbances is obtained with the cationic surfactant cetylpyridinium bromide (CPB) or cetyltrimethylammonium bromide (CTAB). In thepH ranges 8.2–9.0 and 9.8–10.8 the ternary 1:3:3 and 1:4:3 cerium(III)-PF-CPB complexes are formed with molar absorptivities of 9.02 × 104 and 9.86 · 104 lmol–1 cm–1 at 570 and 590 nm, respectively. The corresponding 1:4:2 and 1:3:2 complexes of cerium(IV) are formed in thepH ranges 8.4–9.0 and 9.8–10.6 in the presence ofCTAB andCPB, respectively. Their molar absorptivities are 8.00·104 and 8.56·104lmol–1 cm–1 at 570 and 590 nm, respectively. The stability constants of the studied complexes have been determined and a spectrophotometric method has been developed to determine the cerium content in monazite concentrate.
Komplexierungsreaktionen von Cer(III und IV) mit 9-Phenyl-2,3,7-trihydroxy-6-fluoron in Gegenwart kationischer oberflächenaktiver Stoffe
Zusammenfassung Es wurden Komplexierungsreaktionen von Cer(III und IV) mit 9-Phenyl-2,3,7-trihydroxy-6-fluoron (H3 PF) in Gegenwart und auch ohne oberflächenaktive Stoffe und Schutzkolloide untersucht. Maximale Verstärkung der UV-VIS-Absorption wurde mit den kationischen oberflächenaktiven Verbindungen Cetylpyridiniumbromid (CPB) und Cetyltrimethylammoniumbromid (CTAB) erreicht. ImpH-Bereich von 8.2–9.0 und 9.8–10.8 bildeten sich die ternären 1:3:3 und 1:4:3 Cer(III)-PF-CPB-Komplexe mit molaren Extinktionskoeffizienten von 9.02·104, bzw. 9.86·104lmol–1 cm–1 bei 570 bzw. 590 nm. Die entsprechenden 1:4:2 und 1:3:2 Cer(IV)-Komplexe wurden impH-Bereich 8.4–9.0 und 9.8–10.6 in Gegenwart vonCTAB undCPB gebildet, wobei die Extinktionskoeffizienten bei 8.00·104, bzw. 8.56·104 lmol–1 cm–1 bei 570 bzw. 590 nm lagen. Es wurden die Stabilitätskonstanten der Komplexe bestimmt und es wurde eine spektrophotometrische Methode zur Bestimmung von Cer in Monazitkonzentrat entwickelt.相似文献