采用高效液相色谱-串联质谱法测定食用植物油中4-壬基酚的含量。食用植物油样品用乙酸乙酯-环己烷（1+1）混合液溶解，以凝胶渗透色谱净化，在线收集14.0~17.0 min的馏分，于30℃浓缩至近干，加甲醇1.0 mL溶解残余物。在高效液相色谱分离中，以Agilent Poroshell120ec-C₁₈色谱柱为分离柱，以不同体积比的甲醇和0.1%（质量分数）氨水溶液的混合液为流动相进行梯度洗脱。在串联质谱分析中，采用电喷雾负离子源和多反应监测模式检测。所用内标物为4-n-NP-D₄，以空白玉米油为基质。4-壬基酚的线性范围为0.25~160 μg·kg^-1，方法的检出限（3S/N）为1.00 μg·kg^-1。在2.00，5.00，10.00 μg·kg^-1等3个浓度水平进行加标回收试验，测得回收率为99.0%~115%，测定值的相对标准偏差（n=6）为4.3%~8.1%。

HPLC-MS/MS was applied to the determination of 4-nonyl phenol (4-NP) in edible vegetable oils. The sample of edible vegetable oil was dissolved in mixture of ethyl acetate-cyclohexane (1+1),and then purified by gel permeation chromatography, through collecting the fractions between 14.0 to 17.0 min, and the solution obtained was evaporated to near dryness at 30℃. The residue was taken up and diluted to 1.0 mL with methanol. In HPLC separation, Agilent Poroshell120ec-C₁₈ chromatographic column was used as stationary phase, and the mixture of methanol and 0.1% (mass fraction) ammonia solution mixed in different ratios was used as mobile phase in gradient elution. In MS/MS determination, ESI^- and multi-reactions monitor mode were adopted. 4-n-NP-D₄ was used as internal standard and blank corn oil was used as matrix. Linearity range of 4-NP was found between 0.25 μg·kg^-1 and 160 μg·kg^-1 with detection limit (3S/N) of 1.00 μg·kg^-1. Tests for recovery were made by standard addition method at 3 concentration levels of 2.00, 5.00, 10.00 μg·kg^-1, giving values of recovery and RSD's (n=6) in the ranges of 99.0% to 115% and 4.3% to 8.1% respectively.