الملخص الإنجليزي
In the present work, novel, efficient and stable solid-state electrochemiluminescence (ECL) sensors were developed base on immobilization of tris(2,2 bipyridine)Ruthenium(I) (Ru(bpy)32+) onto electropolymerized conducting polymers. 4-aminodiphenylamine (Padpa) was electropolymerized at glassy carbon electrode (GCE) via potentiodynamic repetitive cycles in acidic medium. The resulting polymeric surface film was used as base matrix for electrodeposited Ru(II) complex, Ru.Padpa/GCE. For better performance and stability, the polymeric film was subjected to alkaline treatment followed by redoped Ru(bpy)32* to give Ru.t Padpa/GCE sensor. A further modification was applied by incorporation of gold nanoparticals (AuNP) prior to redoposite of Rubpy)32. The resulting RuAuNPs. Ru.t-Padpa/GCE sensor showed excellent stability and ECL activity. The prepared sensors at different stages were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and used for analysis of tripropylamine (TPA) and chlorpheniramine meleate (CPM). RuAuNPs.Ru.t Padpa/GÇE was applied also to quantify drugs such as buspirone (BUS), diphenhydramine (DPH), triprolidine (TPH) and ephedrine (EPH) in their pharmaceutical formulations samples. A composite solid-state ECL sensor constructed by the electrochemical polymerization of a matrix contains Ru(II) complex and 4-amino-3 hyrdroxynaphthylene sulfonic acid (AHNSA). The composite film (Ru.PAHNSA/GCE) provides a stable and reactive luminescence for the determination of TPA and CPM with a detection limit of 12.8 ng/mL and 23 ng/mL, respectively. Incorporation of AuNPs in a similar fashion to the described above was adopted to improve the efficiency of the sensor and to increase the surface amount of Rubpy)32*. The resulting Ru.AuNPs.Ru.PAHNSA/GCE gives rise a larger light emission for ECL analysis of TPA and CPM. Polytyramine (Ptyr) was selected as another base material for doping Ru(II)-complex for its remarkable physical, chemical and mechanical properties. Several stages of surface modifications were conducted including alkaline treatment and incorporation of AuNPs as describe above to construct a stable and efficient ECL sensor. The resulting Ru.AuNPs.Ru.t-Ptyr at GCE and Pt surfaces were fabricated and tested for ECL analysis of TPA and CPM. Interestingly, the Pt-substrate showed a lowered detection limit for CPM than surface materials at GCE-substrate. During the course of this research work, electrochemical sensor based on immobilization of Ru(II) complex onto the moiety of the Ptyr was applied to study the oxidation of CPM. The detection limit was brought down to 132 ng/mL of CPM using differential puls voltammetry (DPV), also thermodynamic and kinetic parameters were evaluated for oxidation of CPM using chronoamperommetry at hydrodynamic conditions. The diffusion coefficient and rate constant for the oxidation of CPM were 2.67 x 10-5 cm2/s and 3.21 x 10-3 cm/s, respectively. Similarly, the Ru.Padpa/GCE sensor was applied for the simultaneous determination of heavy metals in water such as Zn2+, Cd2+, Pb2+ and Cu2+. Moreover, this sensor was applied for the quantification of guaifensesin (GUA) in pharmaceutical preparations with a detection limit of 82 ng/mL.
