Sequential extraction procedures (SEPs) are commonly used to determine speciation of trace metals in soils and sediments. However, the non-selectivity of reagents for targeted phases has remained a lingering concern. Furthermore, potentially reactive phases such as phyllosilicate clay minerals often contain trace metals in structural sites, and their reactivity has not been quantified. Accordin...

Nitrite was formed from hydroxylamine and several oximes by intact cells and extracts of Pseudomonas aeruginosa. The activity was induced by the presence of oximes in the culture medium. Nitroalkanes were not intermediates in the conversion of acetaldoxime, acetone oxime, or butanone oxime to nitrite, since nitromethane inhibited the formation of nitrite from the nitro compounds but not from th...

The synthesis of y-glutamylhydroxamic acid from glutamine and hydroxylamine is catalyzed by glutamine synthetase in the presence of adenosine diphosphate, inorganic phosphate, and magnesium ions (l), and also by other enzyme preparations (2,3) that do not exhibit a requirement for nucleotides or metal ions. The synthesis of y-glutamylhydroxamic acid from glutamic acid and hydroxylamine that is ...

Enzymes capable of catalyzing the hydroxylamine-dependent. oxidation of pyridine nucleotides have been studied in Salmonella typhimurium (1, 2), Escherichia coli (3-5), Bacillus subtilis (6, 7), Azotobacter agile (8, 9), Neurospora crassa (lo), and soybean leaves (11). Siegel, Click, and Monty (1) and Siegel and Monty (2) demonstrated that reduced triphosphopyridine nucleotide-specific hydroxyl...

A series of 5-phenyl-1-(3-pyridyl)-1H-1,2,4-triazole-3-carboxylic acid derivatives 4-10 were synthesized by rearrangement of 4-(3-pyridyl)-hydrazono-2-phenyl-2-oxazolin-5-one 3 in the presence of different nucleophiles to afford derivatives 4, 7, and 8, while hydroxamic acid derivative 6 was prepared from reaction of methyl ester 4 with hydroxylamine hydrochloride. Semicarbazide 9 and thiosemic...

A long-term budget of uranium calculated for a chronosequence of Hawaiian soils demonstrates the importance of mineral aerosol deposition as a geochemical pathway. A series of sequential extractions on the same soils shows a strong association between Fe-oxides and uranium, especially the amorphous and poorly-crystalline Fe-oxides present in intermediate-age soils (20 and 150 ka). Despite inten...

A simple and efficient method for speciation and determination of iron in different water samples was developed. The method is based on ionic liquid ultrasound assisted dispersive liquid–liquid microextraction (IL-USADLLME) followed by spectrophotometric determination. Fe(II) is complexed with 2,4,6-tri(2’-pyridyl)-l,3,5-triazine (TPTZ), neutralized through ion pair formation with sodium dodecy...

THE LOSS OF MERCURY due to volatilization and incomplete removal of oxidizing agents which destroy dithizone are among the major problems in determining mercury in urine. This paper describes a method by which these difficulties are reduced to a minimum. In actual use, this method has been found efficient in screening large numbers of workers exposed to a mercury hazard. Most methods require a ...

In the present study, a new series of 2,6-diaryl-3-methyl-4-piperidones was synthesized by Mannich reaction (condensation) of ethyl-methyl ketone, substituted aromatic aldehydes and ammonium acetate. Oximes and thiosemicarbazone derivatives of 2,6-diaryl-3-methyl-4-piperidones were synthesized by reaction with hydroxylamine hydrochloride and thiosemicarbazide respectively. The chemical structur...

A mixture of acetaminophen, diphenhydramine hydrochloride and pseudoephedrine hydrochloride is used for the symptomatic treatment of common cold. In this study, a derivative spectrophotometric method based on zero-crossing technique was proposed for simultaneous determination of acetaminophen, diphenhydramine hydrochloride and pseudoephedrine hydrochloride. Determination of these drugs was perf...