A novel method for preconcentration of methylmercury and inorganic mercury from water samples was developed involving the determination of ngl(-1) levels of analytes retained on the silica C(18) solid sorbent, previous complexation with ammonium pyrrolidine dithiocarbamate (APDC), by slurry sampling cold vapor atomic absorption spectrometry (SS-CVAAS) in a flow injection (FI) system. Several va...

We examined the stability of uric acid in dilute aqueous ammonium hydroxide solution by mass spectrometry. Uric acid decomposes in ammonium hydroxide even as dilute as 15 mmol/L when the mole ratio of ammonium hydroxide to uric acid is 50:1. There are at least four products of the decomposition, two of which have been identified as allantoin and urea. The slope of the decomposition curve indica...

hours to several days. We changed the concentration of ammonium hydroxide from 1 mmol/L to 2 mmol/L. We again prepared a standard solution of uric acid at the same molar ratio of 1.7:1 with this concentration of 2-mmol/L ammonium hydroxide. With this ammonium hydroxide concentration, uric acid dissolved completely in a few minutes. The standard solution was stable at least 3 months stored in a ...

The significant shift in kinetic and equilibrium behavior of complex formation between Ni2 and 2-amino-cycloŽ . Ž . pentene-1-dithiocarboxylic acid ACDA in a solution of ionic surfactant cetyltrimethylammonium bromide CTAB was studied spectrophotometrically in 0.1 M NaBr medium at 30 C. A model based on distributions of ligand Ž . Ž . ACDA and complex Ni ACDA between aqueous and micellar pseudo...

A rapid flotation method for separation and enrichment of ultra trace amounts of copper(II), cadmium(II), nickel(II) and cobalt(II) ions from water samples is established. At pH 6.5 and with sodium dodecylsulfate used as a foaming reagent, Cu2+, Cd2+, Ni2+ and Co2+ were separated simultaneously with 2-aminocyclopentene-1-dithiocarboxylic acid (ACDA) added to 1 l of aqueous solution. The propose...

The objective of this study was to determine the optimal inclusion rate of dietary formic acid-ammonium formate (composition by weight was 62% formic acid and 37% ammonium formate) in nursery and grower-finisher diets or grower-finisher diets only. At weaning (d 21 +/- 2), 224 pigs (equal numbers of gilts and barrows) were blocked by BW within sex (28 pigs per BW block, 4 pigs per pen) and assi...

The pyrrolidine ring of nicotine has been shown to be formed from ornithine, glutamic acid, and proline (l-5). Although little information is available concerning the interrelationship of these three amino acids in higher plants, Al-pyrrolinedcarboxylate (in equilibrium with glutamic semialdehyde) has been shown to be a key intermediate in their interconversion in animals and microorganisms (6,...

Hydrophobic task specific ionic liquid (TSIL) functionalized 2-mercaptobenzothiazole (MBT) was synthesized and characterized by NMR and HRMS. The capability of TSIL-MBT for the selective separation and preconcentration of Cd(2+), which was determined by flame atomic absorption spectrometry (FAAS) from water and food samples, was investigated. The TSIL-MBT with high selectivity for the extractio...