提出了用气相色谱法测定珠光剂中不同碳链脂肪酸酯组分的含量。样品与0.5 mol·L-1氢氧化钾溶液冷凝回流反应60 min后,于反应液中加入140 g·L-1三氟化硼-甲醇溶液进行衍生反应。衍生产物经INNOWAX-1毛细管柱(30 m×0.25 mm,0.25 μm)分离,用氢火焰离子化检测器测定。按试验方法对棕榈酸甲酯和硬脂酸甲酯的标准溶液进行测定,测得其质量浓度均在0.1~20 g·L-1范围内与峰面积呈线性关系,检出限(3S/N)均为4 μg·L-1。对几种珠光剂进行分析,其衍生化反应的转化率在97.5%以上;棕榈酸甲酯和硬脂酸甲酯的回收率分别在98.0%~99.5%和97.8%~98.9%之间,测定值相对标准偏差(n=6)均为0.08%。

GC was applied to the determination of esters of fatty acids with different carbon chains in pearlescent agents. The sample (0.200 0 g) was refluxed with 5 mL of 0.5 mol·L-1 KOH methanol solution for 60 min, and 20 mL of 140 g·L-1 boron trifluoride methanol solution were added to the reaction mixture for derivatization. The derivates were separated on INNOWAX-1 capillary column (30 m×0.25 mm, 0.25 μm) and determined by FID. Standard solutions of methyl palmitate and methyl stearate were analyzed by the proposed method, giving linear relationships between values of peak area and mass concentration of the 2 esters in the same range of 0.1-20 g·L-1, with same detection limits (3S/N) of 4 μg·L-1. Recovery was tested by addition of the above mentioned 2 standards at 3 concentration levels, giving values of recovery in the ranges of 98.0% to 99.5% and 97.8% to 98.9% respectively, with same RSD′s (n=6) of 0.08%. In analyzing samples of 6 different batches, values of conversion rate of derivatization calculated were higher than 97.5%.