Spectrophotometric Determination of Zinc Using 7-(4-Nitrophenylazo)-8-Hydroxyquinoline-5-Sulfonic Acid

Abstract

Um novo método espectrofotométrico para determinação de zinco(II) é proposto usando um derivado da 8-hidroxiquinolina, o ácido 7-(4-nitrofenilazo)-8-hidroxiquinolina sulfônico (p-NIA-ZOXS). A reação entre o p-NIAZOXS e o zinco(II) é rapida em pH 9,2 e o complexo formado é estável por pelo menos 24 h. O método permite a determinação de zinco na faixa de 0,05 a 1,0 µg mL -1 com absortividade molar de 3,75 x 10 4 L mol -1 cm -1 e limite de detecção de 15 ng mL -1 . O método proposto foi aplicado na determinação de zinco em produtos farmacêuticos e ligas de cobre, onde a precisão (R. S. D. < 2%) e exatidão obtidas foram satisfatórias.A sensitive and selective spectrophotometric method is proposed for the rapid determination of zinc(II) using an 8-hydroxyquinoline derivative, 7-(4-nitrophenylazo)-8-hydroxyquinoline-5-sulfonic acid (p-NIAZOXS), as a new spectrophotometric reagent. The reaction between the p-NIA-ZOXS and zinc(II) is instantaneous at pH 9.2 (borax buffer) and the absorbance remains stable for over 24 h. The method allows the determination of zinc over the range of 0.05-1.0 µg mL -1 with a molar absorptivity of 3.75x10 4 L mol -1 cm -1 and features a detection limit of 15 ng mL -1 . The proposed method has been successfully applied to the determination of zinc in several pharmaceutical preparations and copper alloys. The precision (R.S.D. < 2%) and the accuracy obtained were satisfactory.

Novel small molecule inhibitors of botulinum neurotoxin A metalloprotease activity

“…It is possible that this ion might bind to polar residues in or near the substrate binding cleft, blocking access to the catalytic site. Inhibitors NSC 86372 and 130796 both contain an 8-hydroxyquinoline moiety (Table 1), which is known to chelate metal ions [29]. Based on our analyses, both of these molecules do chelate the BoNT/A LC catalytic zinc.…”

Spectrophotometric Determination of Zinc in Pharmaceutical Medication Samples Using 8-Hydroxyquinoline Reagent

“…In pharmaceutical preparations Zn-II has been marked spectrophotometrically, mostly with the employ of azo derivatives (Bhalotra, & Duri, 1999) and (Korn, et al, 1999).…”

Studies on New Reagent Beryllon III and its Applications in Water Sample

“…Zinc compounds have biocidal activity because they precipitate and denature the bacterial proteins. For this reason it has been used in dermatology as an antiseptic and disinfectant agent, in ophthalmic solutions, mouthwashes and mineralvitamin preparations 1,2 . Zinc deposits are not only important commercially for the zinc they contain, but also because of their association with other valuable elements.…”