a simple and rapid spectrophotometric method for the determination of nitrite in water and soil preparation samples has been developed. determination of nitrite is based on diazotization of p-nitro aniline with nitrite and subsequent coupling with 4-amino-3-hydroxynaphthalene-1-sulfonic acid in hydrochloric acid. the factors affecting the reaction i.e. concentration of p-nitro aniline, concentr...

Recently we reported the presence of an enzyme system, widely distributed in microorganisms,’ which catalyzes the exchange of the amide group of asparagine and glutamine with hydroxylamine (2) or isotopic ammonia (3). These enzymatic potencies, which were named tentatively glutamoand aspartotransferase activities (GTF and ATF), occur also in plant material (4) and mammalian tissues (5). In this...

Perfluoroalkyl acids (PFAAs) are a group of persistent organic substances that are surface active and water and fat/oil repellent. Due to the wide use and persistence of PFAAs they are present everywhere in the environment, and humans are exposed via food, drinking water and the use of products containing PFAAs and related compounds. We investigated blood serum levels of ten perfluoroalkyl carb...

sulfonic acid functionalized sba-15 (sba-pr-so3h) as a new nanoporous acid catalyst was used in the one-pot synthesis of polyhydroquinolines derivatives via the hantzsch four component condensation reaction of aldehydes, b-ketoesters, dimedone and ammonium acetate under solvent free conditions with short reaction time in excellent yields. sba-pr-so3h was proved to be an efficient heterogeneous ...

The differential scanning colorimetry (DSC) thermooxidative stability of new copolymers styrene-sulfonic acid and N-vinylimidazole obtained by radical copolymerization in a DMF solution an argon atmosphere has been studied

According to the nomenclature rules of IUPAC the dihedral angle describing the relative orienta­ tions of the two ends of the molecule should be de­ fined as 0° in 1 a and as 180° in lb [3], We refer to l a as the syn conformer and to lb as anti. A mi­ crowave study of gaseous hydroxylamine has shown that the predominant conformer is syn [4]. A microwave study of O-methyl hydroxylamine [5], and...