超声波提取-高效液相色谱/电喷雾离子化质谱法测定白萝卜中植物生长调节剂

建立白萝卜中2-萘氧乙酸、2,4-D、萘乙酸3种植物生长调节剂同时测定的高效液相色谱-电喷雾离子化质谱分析方法。采用Diamonsil C18色谱柱(250mm×4.6mm，5μm)，以V(0.01mol/L甲酸-甲酸铵缓冲溶液，pH4):V(甲醇)=30:70为流动相，流速为0.7mL/min，采用选择负离子监测模式对各物质的定量离子进行监测。结果表明，3种植物生长调节剂在8min内实现快速基线分离，且在0.01～10μg/mL范围内线性关系良好。2-萘氧乙酸、2,4-D以及萘乙酸的方法检出限分别为0.0018、0.004、0.003mg/kg。在0.01、0.05mg/kg和0.50mg/kg三个水平上对白萝卜进行加标回收实验，平均回收率在77.56%～105.08%之间，相对标准偏差在3.48%～15.88%之间。该方法用于白萝卜中植物生长调节剂的检测，结果良好。

Determination of Plant Growth Regulators in Radish by Ultrasound-Assisted Extraction and Liquid Chromatography-Electrospray Ionization Mass Spectrometry

A new method for the determination of plant growth regulators including 2-naphthoxyacetic acid,2,4dicholrophenoxyacetic acid and 1-naphthlcetic acid in radish was developed by liquid chromatography-electrospray ionization mass spectrometry(LC-ESI/MS).The chromatographic separation was performed on a Diamonsil C18 column(250 mm × 4.6 mm,5 μm) by using a mobile phase made up of 0.01 mol/L formic acid-ammonium buffer solution(pH 4) and methanol(30:70,V/V) at a flow rate of 0.7 mL/min.The mass spectrometric quantitative analysis was based on selective ionic measurement by electrospray ionization in the negative ion mode.Baseline separation was achieved for three plant growth regulators within 8 min.Good linearity was observed in the range of 0.01-10 μg/mL for all of them.The detection limit at a signal to noise ratio of 3 was 0.0018 mg/kg for 2-naphthoxyacetic acid,0.004 mg/kg for 2,4-dicholrophenoxyacetic acid and 0.003 mg/kg for 1-naphthlcetic acid,respectively.Under optimal conditions,the average recovery rate and relative standard deviation were 77.56%-105.08% and 3.48%-15.88% at spike levels of 0.01,0.05 mg/kg and 0.50 mg/kg,respectively.Therefore,this method is suitable for the determination of plant growth regulators in radish.