title: [Determination of hexane in the acid cluster of caprolactam by high performance liquid chromatography with indirect photometric detection].
abstract: 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, nonabsorption 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 x 4.6 mm, 5 microm). 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 degrees C. 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.
authors.affiliation: Engineering Research Center of Chemical Process Simulation and Optimization of Ministry of Education, College of Chemical Engineering, Xiangtan University, Xiangtan 411105, China.
authors.forename: Linan
authors.initials: L
authors.lastname: Li
authors.forename: Zhengkang
authors.initials: Z
authors.lastname: Duan
authors.forename: Hongyan
authors.initials: H
authors.lastname: Zeng
authors.forename: Yuping
authors.initials: Y
authors.lastname: He
authors.forename: Qiuyun
authors.initials: Q
authors.lastname: Chen