Studies On Electrochemical Detection Of Artemisinin (Qinghaosu) And Its Reactions With Bio-molecules

Artemisinin(QHS) is a low toxicity and high effect antimalarial compound. It is toxic for many tumour cells. The studies of artemisinin and its derivations cause the worldwide interest. The investigations in these field make advance in recent years.This paper studied the artemisinin with electrochemical technique. And discover that there was a irreversible reductive peak at the Ag electrode or GC electrode when the artemisinin was in 20% ethanol (v/v)+ Britton-Robinson buffer solution (pH=7.2). The potential was -0.64V (vs. SCE) at Ag electrode and -0.87V at GC electrode. Compared the electrochemical behavior of artemisinin at these two electrode. Established the quantitative analysis method of artemisinin with second differential linear sweep voltammetry technique, at GC electrode, linear relationship range from 1.0×10-5-1.0 ×10-3mol/L(.r= 0.9961), the detection limit was 5.0x1 O^mol/L, at the Ag electrode, linear relationship range from6.0×10-6-1.0×10-3mol/L (r=0.9997) the detection limit was 2.0×10-6mol/L. Compared with UV detection method which described in the codex of the people's republic of china. The result was satisfied.This paper studied the electrochemical catalyzing of artemisinin by hemin. The result indicated that hemin can catalyze the electrochemical reduce of artemisinin. At Ag electrode, the potential of artemisinin lowed 90mV. At GC electrode, the potential of artemisinin lowed 320mV. And discussed the catalyzing mechanism. What's more, this paper also studied the electrochemical catalyzing of artemisinin by Hb layer-by-layer film which assembling on the electrode, the Hb layer-by-layer films were characterized by AFM, fluorescence spectrum and UV spectrum.The electrochemical behavior of L-cysteine(or glutathione)-artemisinin binary system and L-cysteine(or glutathione)-artemisinin-surfactant ternary system were studied. The result indicated that when the concentration of artemisinin was 1.0×10-3mol/L, CL-cys(or COSH) > 2.0×10-5mol/L, the adducts of L-cysteine (or glutathione)-artemisinin were formed in the binary system . This bi-adducts were reduced at the potential of-1.03V (or -0.96V). When the concentration of artemisinin was 1.0×10-3mol/L, CL-Cys(or CGSH) >4.0×10-5mol/L, added the positive surfactantDBDAB, the tri-adducts of L-cysteine (or glutathione)-artemisinin-DBDAB were formed in the ternary system. This tri-adducts were reduced at the potential of -0.93V (or -0.88V). The adducts were characterized by IR spectrum and UV spectrum The mechanisms of the bi-adducts and tri-adducts formed at the surface of the electrode were disccused.