title: Fluorimetric determination of some sulfur containing compounds through complex formation with terbium (Tb+3) and uranium (U+3).
abstract: Two simple, sensitive and specific fluorimetric methods have been developed for the determination of some sulphur containing compounds namely, Acetylcysteine (Ac), Carbocisteine (Cc) and Thioctic acid (Th) using terbium Tb+3 and uranium U+3 ions as fluorescent probes. The proposed methods involve the formation of a ternary complex with Tb+3 in presence of Tris-buffer method (I) and a binary complex with aqueous uranyl acetate solution method (II). The fluorescence quenching of Tb+3 at 510, 488 and 540 nm (lambda(ex) 250, 241 and 268 nm) and of uranyl acetate at 512 nm (lambda(ex) 240 nm) due to the complex formation was quantitatively measured for Ac, Cc and Th, respectively. The reaction conditions and the fluorescence spectral properties of the complexes have been investigated. Under the described conditions, the proposed methods were applicable over the concentration range (0.2-2.5 microg ml(-1)), (1-4 microg ml(-1)) and (0.5-3.5 microg ml(-1)) with mean percentage recoveries 99.74+/-0.36, 99.70+/-0.52 and 99.43+/-0.23 for method (I) and (0.5-6 microg ml(-1)), (0.5-5 microg ml(-1)), and (1-6 microg ml(-1)) with mean percentage recoveries 99.38+/-0.20, 99.82+/-0.28 and 99.93+/-0.32 for method (II), for the three cited drugs, respectively. The proposed methods were successfully applied for the determination of the studied compounds in bulk powders and in pharmaceutical formulations, as well as in presence of their related substances. The results obtained were found to be in agree statistically with those obtained by official and reported ones. The two methods were validated according to USP guidelines and also assessed by applying the standard addition technique.
authors: National Organization for Drug Control and Research (NODCAR), 6 Abu Hazem. Pyramids, P.O. Box 29, Giza, Egypt. Dr_elhamtaha@hotmail.com
authors: Elham Anwer
authors: EA
authors: Taha
authors: Nagiba Yehya
authors: NY
authors: Hassan
authors: Fahima Abdel
authors: FA
authors: Aal
authors: Laila El-Sayed Abdel
authors: Lel-S
authors: Fattah
mesh_terms: D000111:Acetylcysteine / Q000032:analysis / Q000737:chemistry; D002233:Carbocysteine / Q000032:analysis / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000737:chemistry; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013457:Sulfur Compounds / Q000032:analysis* / Q000737:chemistry; D013725:Terbium / Q000737:chemistry*; D008063:Thioctic Acid / Q000032:analysis / Q000737:chemistry; D014501:Uranium / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D009942:Organometallic Compounds; D004364:Pharmaceutical Preparations; D013457:Sulfur Compounds; D013725:Terbium; C005460:uranyl acetate; D014501:Uranium; D008063:Thioctic Acid; D002233:Carbocysteine; C067490:terbium chloride; D000111:Acetylcysteine