采用离子对高效液相色谱法,结合峰面积归一化法测定并计算脂肪烷基二甲基苄基季铵盐的平均相对分子质量(M)。用C18键合硅胶色谱柱(4.6 mm×250 mm,5 μm)作固定相,以含10 mmol·L-1戊基磺酸的乙腈-水(95+5)溶液为流动相,对试液进行离子对色谱分离。于波长262 nm处用二极管阵列检测器进行测定。方法用于样品1227的平均相对分子质量的测定,测得M为344.5,经F和t检验,测定值与气相色谱法测定结果一致。

Mean relative molecular mass (M) of alkyldimethylbenzyl-quaternaryammonium salt was determined and calculated by ion-pair HPLC with peak area normalization. The sample solution was separated on C18 silicon gel bonding chromatographic column (4.6 mm×250 mm, 5 μm) with mixed solution of methanol and water in the ratio 95 to 5 by volume (containing 10 mmol·L-1 pentyl sulfonic acid) as mobile phase, and detected at 262 nm by diode array detector (DAD). The proposed method was applied to the determination of M of the sample 1227, value of M found was 344.5. Analytical result by the present method was compared with that by GC, as verified by F-test and t-test, no significant difference was found.