1 Introduction The underground brine resources distributing widely in Sichuan Basin,China have drawn worldwide attention due to their unusual element abundance and excellent quality.
邻苯二甲酸二甲酯在4.5 m L柠檬酸-Na2HPO4(pH 7.12)缓冲溶液、2.0 m L 0.5 mol/L KCl溶液、6.0 m L 5.0×10-4 mol/L十二烷基硫酸钠底液中,于起始电位-0.30 V(饱和甘汞电极(saturated calomel electrode,SCE))、峰电位(Ep)-1.18 V(vs.SCE)左右处产生一个灵敏的极谱还原波,该波的二阶导数峰电流(Ip')与邻苯二甲酸二甲酯的质量浓度在5.913~177.4μg/m L范围内呈良好的线性关系,检出限为0.58μg/m L。本法操作简单、快速、准确,用于白酒中邻苯二甲酸二甲酯的测定,结果令人满意。
In order to utilize the brine resources in China, the solid-liquid equilibria in quaternary system Li＋, K＋//SO42 , B4O72 -H2O at 288 K was studied by the isothermal solution equilibrium method. Solubilities and densities of solutions were determined experimentally. According to the experimental data, the equilibrium phase diagrams, density-composition diagram and corresponding water content diagram of the quaternary system were plotted. Double salt KLiSO4 was found in the reciprocal quaternary system Li＋, K＋//SO42-, B4O72 -H2O at 288 K. The quaternary system has three invariant points, seven univariant curves and five fields of crystallization. The five crystalliza- tion regions correspond to Li2B4O7.3H2O, LizSO4-H2O, K2B4O7-4H2O, K2SO4 and KLiSO4, respectively. The crystal- lization field of salt LizB4O7 3H20 is the largest, whereas that of Li2SO4 H2O is the smallest. The experimental results show that LizSO4 H2O has a strong salting-out effect on other salts.
SANG ShihuaFU ChaoZHANG TingtingZHANG XuepingXIAO Longjun
