Oxidation Characteristics of the Reactivity Between Pyrite and Aqueous Arsenate

Natural pyrites contain high levels of adsorbed and structurally incorporated arsenic(As),which may simultaneously result in the release of As and affect the oxidation process of pyrite.However,the oxidation and electrochemical behaviors of As on the oxidation reactivity of pyrites are still not clear.In this study,pyrite was prepared by a hydrothermal method and applied to study the oxidation mechanism between pyrite and aqueous arsenate.Analyses of X-ray diffraction,X-ray photoelectron spectroscopy,and scanning electron microscopy demonstrate that the as-prepared sample is an octahedron-like pyrite with high purity and crystallinity.The interaction between As(V)and pyrite as well as the electrochemical behaviors of pyrite oxidation in the presence of aqueous arsenate were investigated under acidic conditions by an ion analysis method,cyclic voltammetry(CV),Tafel,and electrochemical impedance spectroscopy(EIS).The results of the chemical reaction indicate that electrons are transferred from S 22-to dissolved oxygen with the formation of SO 42-in the initial As(V)concentration range of 0–0.3 mmol/L.In the initial As(V)concentration range of 0.4–1.2 mmol/L,electrons are transferred from S 22-to As(V)with the formation of elemental S 0 and As(III).The CV,the Tafel plot and EIS analyses indicate that aqueous arsenate in an electrolyte promotes oxidation reactivity and passivation of the pyrite electrode.Moreover,the electron transfer rate increases with increasing aqueous arsenate concentration in the electrolyte.

高效液相色谱法测定大鼠血浆中阿昔洛韦浓度及其与吉非替尼药物相互作用的研究

由于阿昔洛韦水溶性高,较难用普通高效液相色谱法测定其血浆中的药物浓度。本研究建立并验证了测定大鼠血浆中阿昔洛韦浓度的高效液相色谱方法,并将该方法应用于与吉非替尼的药物相互作用研究中。采用Platisil ODS柱(4.6 mm×250 mm,5μm,迪马科技),检测波长254 nm,蛋白沉淀后再用甲基叔丁基醚萃取进行样本处理。阿昔洛韦浓度在0.2–40μg/mL范围内具有良好的线性关系(r^(2)=0.9999),本方法批间和批内精密度均小于8%,批间和批内准确度偏差不超过10%。该方法已成功应用于大鼠体内吉非替尼和阿昔洛韦的药物相互作用研究中。结果显示,同时服用吉非替尼可使阿昔洛韦的吸收增加3倍,这为临床表皮生长因子-酪氨酸酶抑制剂与阿昔洛韦的合用提供了参考。