高效液相色谱-间接光度检测法测定己内酰胺酸团中的正己烷含量

Determination of hexane in the acid cluster of caprolactam by high performance liquid chromatography with indirect photometric detection

采用在流动相中添加有紫外吸收的本底试剂的方法,利用高效液相色谱-间接光度检测法直接测定己内酰胺酸团中无紫外吸收的正己烷含量。考察了流动相组成、本底试剂的种类和浓度、波长梯度等对测定的影响。确定的高效液相色谱条件：色谱柱为Agilent HC-C18柱（250mm×4.6mm,5μm）,流动相为含1.17mmol/L1,5-萘二磺酸（本底试剂）的甲醇-水（85∶15,v/v）溶液,柱温为35℃,流速为1.0mL/min,并采用设定波长梯度的方法调整系统峰和被测峰的相对大小。该分析方法的线性范围为0.5-20mg/kg,相关系数为0.999 93,相对标准偏差为2.53%,检出限为0.03mg/kg,加标回收率为98.45%-102.3%。方法简单,选择性好,灵敏度高,抗干扰强,可快速准确地测定实际样品中的正己烷。

An indirect photometric detection method for the determination of hexane in the acid cluster of caprolactam by high performance liquid chromatography was developed.Ultraviolet（UV） absorption background reagents were added in the mobile phase,and the hexane,non-absorption in ultraviolet region,was directly determined by a UV detector.The effects of the mobile phase composition,species and concentration of the background reagents etc.on the analyzed results were studied.The optimization of the separation was performed on an Agilent HC-C18 column（250 mm×4.6 mm,5 μm）.A solution of methanol-water（85∶15,v/v） containing 1.17 mmol/L 1,5-naphthalene disulfonic acid was used as mobile phase at a flow rate of 1.0 mL/min and the column temperature was set at 35 ℃.The gradient of wavelength was adopted to adjust the relative size of systematic peaks and the target peaks.The linear relationship in the range of 0.5-20 mg/kg with a correlation coefficient of 0.999 93 in this method was obtained.The recoveries and relative standard deviation for the hexane in the acid cluster of caprolactam were 98.45%-102.3% and 2.53%,respectively.The detection limit was 0.03 mg/kg.The method is simple,and has good selectivity,high sensitivity and strong anti-interference ability for the accurate determination of hexane in practical samples quickly.