溶剂浮选-气相色谱法测定氧化铝生产过程中的添加剂硅甲基环己基己酸钠和二十一烷烃

Solvent flotation-gas chroma tographic determination of alumina production additives:sodium methylsilyl cylohexyl hexanoate and henicosane

选择环己烷与环己酮(质量比1∶1.2)的混合物为浮选溶剂,样品经酸化,CH3OH/BF3甲酯化,以邻苯二甲酸为内标,采用溶剂浮选-气相色谱法测定了氧化铝生产过程中铝酸钠溶液里加入的添加剂硅甲基环己基己酸钠(SHNa)和二十一烷烃。结果表明,硅甲基环己基己酸(SH)、二十一烷烃与内标的质量比均在0.1～10范围内分别和其对应的峰面积比呈良好的线性关系(SH:r=0.999 7,二十一烷烃:r=0.999 6),SH和二十一烷烃的检出限分别为0.11 mg/L和0.01 mg/L。用本方法测定铝酸钠溶液中的SHNa和二十一烷烃,相对标准偏差均为1.0%～1.4%,加标回收率均为96%～98%。

With the mixture of cyclohexane and cyclohexanone（1∶1.2） as flotation solvent,samples were acidified,methylated with CH3OH-BF3,then sodium methylsilyl cyclohexyl hexanoate（SHNa） and henicosane,which were added as additives in sodium aluminate solution in alumina production process,were determined by solvent flotation-gas chromatography with diethyl phthalate as internal standard.The results indicated that the mass ratio of methylsilyl cyclohexyl hexanoate（SH） and henicosane to the internal standard in the range of 0.1-10 were linear to the corresponding peak area respectively（r = 0.999 7 for SH and r = 0.999 6 for henicosane）.The detection limit of SH and henicosane were 0.011 mg/L and 0.01 mg/L respectively.This method has been applied to determine SHNa and henicosane in the sodium aluminate solution.The relative standard deviations（RSD） of SHNa and henicosane were both 1.0 %-1.4 % and the recoveries were both 96 %-98 %.