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  • 1
    Electronic Resource
    Electronic Resource
    Determination of traces of gallium in biological materials by fluorometry (1985)
    s.l. : American Chemical Society
    Analytical chemistry 57 (1985), S. 2309-2311 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac00289a031
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  • 2
    Electronic Resource
    Electronic Resource
    Acid/extraction treatment of bivalves for organotin speciation (1997)
    Springer
    Fresenius' journal of analytical chemistry 357 (1997), S. 1007-1009 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A method is described for leaching of nanogram amounts of monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT), monophenyltin (MPT), diphenyltin (DPT), triphenyltin (TPT), and monomethyltin (MMT) from bivalves. The procedure is based on soaking the samples in a water-hydrogen bromide mixture (1:1) with magnetic stirring for 30 min followed by extraction with a 0.04% (w/v) tropolone solution in dichloromethane for 2 h. Organotins are determined by GC-FPD after clean-up through a Florisil column and fat hydrolysis by 1mol/L NaOH, followed by derivatization through Grignard pentylation. The method has been applied for an investigation of the occurrence of organotins in bivalves in south-west Spain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050294
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  • 3
    Electronic Resource
    Electronic Resource
    Derivatives of 2-thiohydantoin as spectrophotometric analytical reagents. III (1982)
    Springer
    Microchimica acta 78 (1982), S. 363-369 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Synthese, die Kennzahlen, die Eigenschaften der Furfural-, Thiophenal-, Pyrrolal-, Acetal-, Propional- sowie des Zimtsäurealdehyd-Derivates des 2-Thiohydantoins und deren Reaktionen mit Metallionen wurden untersucht. In wäßriger Lösung kommen diesen Reagenzien zwei pK-Werte zu. Sie geben empfindliche Farbreaktionen mit Pd(II), Cu(I) und (II), Ag(I) und Hg(II). Die Reaktivität der genannten Derivative wurde untersucht und der Einfluß des mit 2-Thiohydantoin verbundenen aromatischen Ringes daraus ermittelt.
    Notes: Summary The synthesis, characteristics, properties and reactions with metallic ions of the furfural-, thiophenal-, pyrrolal-, cinnamal-, acetal-, and propional-derivatives of 2-thiohydantoin have been studied. The reagents exhibit twopK values in aqueous solution, and sensitive colour reactions with Pd(II), Cu(I) and (II), Ag(I) and Hg(II). A comparison has been made of the reactivity of all the 2-thiohydantoin derivatives we have studied to date and conclusions have been drawn regarding the influence of the aromatic ring connected to 2-thiohydantoin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01197985
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  • 4
    Electronic Resource
    Electronic Resource
    Derivatives of carbohydrazide, thiocarbohydrazide and diaminoguanidine as photometric analytical reagents. III (1983)
    Springer
    Microchimica acta 81 (1983), S. 159-169 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung 1,3-Bis(2-pyridyl)-methylenaminothioharnstoff (PMAT) und 1,3-Bis-(2-pyridyl)-methylenaminoguanidin (PMAG) wurden auf ihre Eignung als selektive spektrophotometrische Reagenzien für Eisen geprüft. PMAT gibt in saurem Medium mit Fe(II) eine Rotfärbung mit dem Absorptionsmaximum bei 590 nm und der molaren Absorptivität 7,2·103l·mol−1·cm−1. PMAG gibt ebenfalls eine Rotfärbung. Die Reaktion bei pH 4,2 ist sehr empfindlich (ε=2,09·104l· mol−1·cmr−1 bei 570 nm). Die beiden Reagenzien wurden zur Bestimmung des Eisens in Erzen und Legierungen verwendet.
    Notes: Summary 1,3-Bis[(2-pyridyl)methyleneamino]thiourea (PMAT) and 1,3-bis-[(2-pyridyl) methyleneamino]guanidine (PMAG) have been examined to evaluate their usefulness as selective spectrophotometric reagents for iron. PMAT forms a red colour with iron(II) in acid medium, with maximum absorption at 590 nm, the molar absorptivity being 7.2×103l·mole−1·cm−1. PMAG also gives a red colour and the reaction at pH 4.2 is very sensitive (ε=2.09×104l·mole−1·cm si−1 at 570 nm). The reagents have been applied to the determination of iron in ore and alloys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01497607
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  • 5
    Electronic Resource
    Electronic Resource
    Spectrophotometric determination of copper in beverages, feeding-stuffs, drugs and alloys with 1,3-bis[di(2-pyridyl)methyleneamino]urea (1984)
    Springer
    Microchimica acta 83 (1984), S. 407-416 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung 1,3-Bis[di(2-pyridyl)methylenamino]harnstoff wurde auf seine Eignung als selektives spektrophotometrisches Reagens für Kupfer geprüft. Es gibt in saurer Lösung mit Kupfer eine gelbe Komplexverbindung mit einem Absorptionsmaximum bei 400 nm und einer molaren Absorbanz von 1,49×10−41·mol−1·cm−1. Kupfer läßt sich damit in Gegenwart vielerlei anderer Ionen quantitativ bestimmen. Das Reagens wurde für die Kupferbestimmung in Getränken, Futtermitteln, Drogen und Legierungen verwendet.
    Notes: Summary 1,3-Bis[di(2-pyridyl)methyleneamino]urea has been examined as a selective Spectrophotometric reagent for copper. It gives a yellow complex with copper in acid medium (pH 1), with an absorption maximum at 400 nm, and molar absorptivity 1.49×1041·mole−1· cm−1. Copper can be quantitatively determined with it in the presence of a large number of ions. The reagent has been applied to the determination of copper in beverages, feeding-stuffs, drugs and alloys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01451451
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  • 6
    Electronic Resource
    Electronic Resource
    Differential pulse polarographic determination of pyruvate by “in situ” reaction with Girard-P reagent (1987)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 329 (1987), S. 590-594 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Pyruvic acid condenses with Girard-P reagent to form a hydrazone derivative (PAHPy). From the present polarographic investigations, it was deduced that the two d.p. waves (Ep1 = −0.76 V and shoulder-like peak Ep2 = −1.06 V at pH = 4.5) probably correspond to two kinds of species in equilibrium: the cyclized lactonic form and the open form of the hydrazone, respectively. The first wave is more appropiate for quantification owing to its higher sensitivity, and in this way pyruvic acid was determined in the concentration range 2.5 × 10−5 to 0.035 mol/l at pH 2.4. Carbohydrates, alcohols and carboxylic acids except α-ketoacids show tolerance limits of a least 10 times the amount of pyruvic acid (mg). The method was satisfactorily applied to evaluate the pyruvate content of milk.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00488209
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  • 7
    Electronic Resource
    Electronic Resource
    Use of cartridges for speciation of organotin compounds in environmental samples (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 8 (1994), S. 553-561 
    Details
    ISSN: 0268-2605
    Keywords: Tributyltin ; dibutyltin ; monobutyltin ; triphenyltin ; diphenyltin ; monophenyltin ; speciation ; C18 cartridges ; C8 cartridges ; preconcentration ; water ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The performance of cartridges with different polar and non-polar stationary phases (C18, C8, C2, phenyl) has been investigated for the quantitative separation of butyltin and phenyltin species (TBT, DBT, MBT, MPT, DPT, TPT), and conditions have been established to optimize the separation, using gas chromatography with a flame photometric detector, to characterize the different organotin species. Optimum separation and preconcentration of organotins is based on retention in a C18 cartridge and elution with 2 cm3 of 1% (v/v) HBr and 0.1% tropolone solution in methanol, being successfully applied to seawater. Finally, the possibilities of the cartridges for selective elution and their use in direct non-chromatographic speciation are discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590080703
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  • 8
    Electronic Resource
    Electronic Resource
    Evaluation of atomic fluorescence spectrometry as a sensitive detection technique for arsenic speciation (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 439-447 
    Details
    ISSN: 0268-2605
    Keywords: high-performance liquid chromatography ; hydride generation ; atomic fluorescence spectrometry ; photo-oxidation ; arsenic speciation ; human urine ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potential of coupling anion-exchange high-performance liquid chromatography, hydride generation and atomic fluorescence spectrometry (HPLC-HG-AFS) for arsenic speciation is considered. The effects of hydrochloric acid and sodium tetrahydroborate concentrations on signal-to-background ratio, as well as argon and hydrogen flow rates, were investigated. Detection limits for arsenite, dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and arsenate were 0.17, 0.45, 0.30 and 0.38 μg l-1, respectively, using a 20-μl loop. Linearity ranges were 0.1-500 ng for As(III) and MMA (as arsenic), and 0.1-800 ng for DMA and As(V) (as arsenic). Arsenobetaine (AsB) was also determined by introducing an on-line photo-oxidation step after the chromatographic separation. In this case the limits of detection and linear ranges for the different species studied were similar to the values obtained previously for As(V). The technique was tested with a human urine reference material and a volunteer's sample. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    GC FPD method for the simultaneous speciation of butyltin and phenyltin compounds in waters (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 6 (1992), S. 279-286 
    Details
    ISSN: 0268-2605
    Keywords: Organotin ; tributyltin ; dibutyltin ; monobutyltin ; triphenyltin ; diphenyltin ; monophenyltin ; speciation ; gas chromatography ; flame photometric detector (FPD) ; water ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the simultaneous determination of nanogram amounts of mono-, di- and tri-butyltin compounds in water. The procedure is based on the conversion of tin compounds to volatile species by Grignard pentylation and analysis using GC with flame photometric detection (GC FPD). The ionic compounds are extracted from diluted acidified (HBr) aqueous solutions by using a pentane-tropolone solution. The extracted organotin compounds are pentylated by a Grignard reagent and purified on a Fluorisil column before analysis by GC FPD. The detection limits are 20 ng dm-3 for butyltin compounds and 50 ng dm-3 for phenyltin compounds. Recoveries from spiking experiments in tap-water and natural seawater matrices, in which no organotin compounds were detected, were greater than 90% for most of the alkyltin compounds.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590060306
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  • 10
    Electronic Resource
    Electronic Resource
    Acid extraction treatment of sediment samples for organotin speciation; occurrence of butyltin and phenyltin compounds on the cadiz coast, south-west spain (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 9 (1995), S. 51-64 
    Details
    ISSN: 0268-2605
    Keywords: tributyltin ; dibutyltin ; monobutyltin ; triphenyltin ; diphenyltin ; monophenyltin ; speciation ; gas chromatography ; flame photometry ; south-west Spain ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for leaching of nanogram amounts of mono-, di and tri-butyltin compounds and mono-, di- and tri-phenyltin compounds from sediments. The procedure is based on soaking the sediments in a water-hydrogen bromide mixture (2:3) with magnetic stirring for 1 h followed by extraction with 0.02% (w/v) tropolone solution in pentane for 2 h. Organotins are determined by GF FPD after clean-up through a Florisil column and derivatization by Grignard pentylation. The method has been applied to the study of water and sediments in different areas of south-west Spain. Predominant species are butyltins, especially tributyltin (TBT), which has high values in waters and sediments of Puerto de Santa Maria and Cadiz Bay, as well as in sediments of the Sancti Petri Channel, which suggests a harmful action on biota. A direct relation has been found beween organotin levels and distance of potential focus determined by boating activities. In addition, the relative occurrence of dibutyltin (DBT) and monobutyltin (MBT) together with TBT has been noted, possibly as a result of a degractation process, and the influence of grain size of sediment and presence of organic matter on organotin accumulation has been studied.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590090109
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