Electrochemical Study And Application Of β-cyclodextrin-coenzyme Q₁₀ Inclusion Complex

Part one Documents reviewTwo aspects of the study of cyclodextrin inclusion complex and carbon paste electrode (CPE) are described respectively. The development of cyclodextrin and the electrochemical study of cyclodextrin inclusion complex are summarized. On the other hand, the recent development of CPE and its applications are described. Part Two Research reportsThe inclusion reaction of coenzyme Q₁₀ with β-cyclodextrin ( β-CD) is studied by the polarographic method. The formation constant, the stoichiometry and the inclusion reaction kinetics of the coenzyme Q₁₀- β-CD inclusion complex are studied. Additionally, the sensitivity for the determination of coenzyme Cho is enhanced by both the formation and the polarographic catalytic wave of the inclusion complex in the presence of iodinate. A novel polarographic method for the determination of coenzyme Cho is proposed in β-CD and iodinate system.The voltammetric behaviors of coenzyme Q₁₀ and human serum albumin (HSA) on CPE are studied respectively. A novel square wave voltammetry is developed on CPE for the determination of coenzyme Q₁₀ in pharmaceutical, as well as HSA in serum.The concrete contents are described as follows: Chapter one Inclusion of coenzyme Cho with β-cyclodextrin by polarographyIn 0.1 mol·L^-1 HAc/NaAc (pH 4.7) buffer-ethanol/water (60:40) medium, coenzyme Q₁₀ is complexed with β-CD to the formation of 1:1 inclusion complex. The formation constant K_f is 1.26×10⁴ L·mol^-1 by polarography, the apparent formation rate constant is 6.64×10^-2min^-1. The change of the reduction peak current of both coenzyme Cho and coenzyme Cho- β-CD inclusion complex with time are alsoexamined under light respectively. The photodegradation apparent rate constant of them are determined. The stability of coenzyme Qio to light is improved in a certain degree due to the formation of the inclusion complex.Chapter Two High sensitive determination of coenzyme Qio in iodinate-j#-cyclodextrin medium by inclusion reaction and catalytic polarographyIn 0.1 mol-L"1 HAc-NaAc (pH 4.7)-5.0xl0'5 mol-L'1 iS-CD-1.2xlO"3 mol-L"1 potassium iodinate-ethanol/water (60:40 v/v) medium, coenzyme Qio- fi -CD inclusion complex yields a sensitive association/parallel catalytic wave at -0.13 V (vs. SCE). The second-order derivative peak current of the catalytic wave is proportion to coenzyme Qio concentration in the range of 6.0xl0"8 2.5xlO"7 mol-L"1, and the detection limit is 1.0x10* mol-L'1.Chapter Three Voltammetric behavior and square-wave voltammetric determination of coenzyme Qio at carbon paste electrodeIn Britton-Robinson (pH 1.98) buffer solution, human serum albumin (HSA) yields two adsorptive reversible reduction waves with peak potential +0.96 V and +0.30 V(vs, SCE). These two waves are one-electron, one-proton waves. The square-wave voltammetric method is proposed for the determination of HSA content in human serum.Chapter Four Voltammetric behavior and square-wave voltammetric determination of coenzyme Qio at carbon paste electrodeIn Britton-Robinson(pH 4.10) buffer solution, coenzyme Qio yields an adsorptive reversible reduction wave with peak potential -0.27 V (vs, SCE). The reduction wave is a one-electron, one-proton wave. The square-wave voltammetric method is proposed for the determination of coenzyme Qio in coenzyme Qio capsule.