溶剂浮选-气相色谱法测定铝酸钠溶液中的硬脂酸钠

Determination of Sodium Stearate in Sodium Aluminate Solution by Solvent Flotation-Gas Chromatography

用溶剂浮选．气相色谱法测定铝酸钠溶液中的硬脂酸钠。选择环己酮为浮选溶剂，样品经1：1（V／V）的盐酸酸化后，以40mL／min的速度通入氮气并以环己酮为浮选溶剂浮选30min进行富集，用CH3OH／BF3在80℃水浴中加热3min进行甲酯化，以毛细管色谱柱PEG-20M（30m×0．32mm，i．d．）分离，邻苯二甲酸二乙酯为内标，氢火焰离子化检测器检测。方法在硬脂酸与内标的质量比在0．1～10范围内呈良好的线性关系（r=0．9997）；硬脂酸钠的相对标准偏差为1．35％（n=7）；回收率为96．9％-98．1％。

A method for the determination of sodium stearate in sodium aluminate solution was developed. Cyclohexanone was selected as the solvent. The samples were acidified with 1 ： 1 （V/V） hydrochloric acid, concentrated by solvent flotation for 30 min with the nitrogen by 40 mL/min speed using cyclohexanone as the solvent, methlated with CH3OH-BF3 by heating up in 80℃ water baths for 3 min and analyzed by gas chromatography with a 30 m × 0. 32 mm （ i. d. ） PEG-20M quartz capillary column and flame ionization detection （ FID）, while diethyl phthalate was used as internal standard. The good linear relationships was observed with the correlation coefficients of 0. 9997 when the mass ratio of fatty acid and internal standard was 0. 1 - 10. The relative standard deviation and recovery for determining sodium stearate were 1.4% （ n = 7 ） and 96.9% - 98. 1% （n =5） respectively.