过氧化氢柱前荧光衍生化液相色谱法测定麻痹性贝毒的研究

Determination of Paralytic Shellfish Poisoning Toxins by Liquid Chromatography with Fluorescence Detection Using Pre-column Derivatization with Hydrogen Peroxide Oxidation

液相色谱-荧光检测法（LC-FLD）测定贝类样品中石房蛤毒素（STX）和decarbamoylsaxitoxin（dcSTX）.样品经30 mmol/L HAc超声提取,C18固相萃取柱净化,2%碱性H2O2荧光衍生,C18色谱柱（4.6 mm×250 mm, 5 μm）分离,以乙腈-0.1 mol/L甲酸铵溶液（5：95,V/V）作流动相,流速1.0 mL/min.结果表明,STX和dcSTX衍生物在7min内获得完全分离.在空白样品中添加标准品使浓度0.01～2.0 μg/g,得到峰面积与浓度呈良好线性,线性相关系数》0.998.添加浓度在0.1、0.8和1.6 μg/g的回收率为87%～97%（n=8）;相对标准偏差为8%～13%.方法检出限（S/N=3）分别为STX 1.0 ng/g和dcSTX 0.3 ng/g.另外,采用四极杆-飞行时间质谱（Q-TOF-MS）对STX和dcSTX衍生物进行了结构解析.

Saxitoxin （STX） and decarbamoylsaxitoxin （dcSTX） were determined by liquid chromatography with fluorescence detection. A shellfish tissue was extracted with 30 mmol/L HAc under ultrasonication, and cleanup of extract was accomplished by solid-phase extraction with a C18 cartridge. Fluorescence derivatization of STX and dcSTX was used with 2% alkaline H2O2 solution. Chromatographic separation was carried out on a C18 cohmn（4.6 mm × 250 mm,5μm）with elution of acetonitrile-0. 1 mol/L ammonium formate solution （5：95, V/V） at a flow rate of 1.0 mL/min. STX and dcSTX derivatives were completely separated in 7 min. The matrix-matched calibration graphs for STX and dcSTX were prepared by injecting extracted blank spiked with increasing amounts of standard ranging from 0. 01 to 2.0 μg/g, giving an acceptable linearity （ r = 0. 9983 and r = 0. 9989） over the test range. Average recoveries and relative standard deviations, by analyzing samples spiked at a level of 0. 1,0.8 and 1.6μg/g, were 87% -97% and 8% - 13%, respectively. The detection limits （ S/N= 3 ） of STX and dsSTX were 1.0 ng/g and 0. 3 ng/g, respectively. The proposed method is very sensitive, simple, fast and reproducible. In addition, the structures of STX and dcSTX derivatives were elucidated using quadrupole time-of-flight mass spectrometry.