海洋沉积物中甾醇类物质的气相色谱/质谱方法分析

Detection of sterols in marine sediments by gas chromatography-mass spectrometry

应用超声提取技术,结合硅胶-中性氧化铝柱层析净化分离,BSTFA+1%TMCS衍生,及气相色谱-质谱定性定量技术,建立了海洋表层沉积物中8种甾醇类化合物的定量分析方法.实验采用正交实验优化了提取过程中提取剂种类、试剂体积和超声时间,同时对比并优化了柱层析淋洗液的配比、用量以及衍生剂的用量.结果表明,50 mL二氯甲烷/甲醇(V/V,2∶1),超声40 min,超声3次,总甾醇的萃取率可达99.6%;3 g硅胶+2 g中性氧化铝层析,35 mL二氯甲烷/甲醇(V/V,9∶1)淋洗净化回收最佳;8种甾醇在0—848μg.L-1范围内有良好的线性关系;方法检测限为1.2—2.4 ng.g-1.在3种浓度水平0.05、0.1和1.0μg.g-1下,其平均回收率为76.2%—100.9%,相对标准偏差为1.0%—10.3%.应用本方法检测大连湾的3个沉积物样品,8种甾醇的含量在0.079—6.833μg.g-1范围内.本方法的灵敏度高、准确度好,适合用于沉积物样品中甾醇物质的检测要求.

An improved method was established to analyze 8 sterols in marine sediments by ultrasonic extraction,silica gel-alumina multilayer column separation,dichloromethane/methanol（V/V,1∶1） eluviating,derivatization（BSTFA＋1%TMCS）,qualitative and quantitative analysis by gas chromatography-mass spectrometry.An orthogonal experimental design was conducted to optimize the type,volume and time of extraction solutions.The condition of eluted solvents and detribalization were also optimal.The results show that the total extraction rate of sterols was 99.6% while 50 mL dichloromethane/methanol（V/V,2∶1）,40 min ultrasonic extraction and 3 times;3 g silica＋2 g neutral alumina column,35 mL dichloromethane/methanol（V/V,9∶1） eluviating purification and recovery were optimal.8 sterols were determined in the concentration range from 0 μg·L-1 to 848 μg·L-1.The detection limit of the method was in the range of 1.2—2.4 ng·g-1.At the spiked levels of 0.05,0.1,1.0 μg·g-1,the mean recoveries were in the range of 76.2%—100.9%,and the relative standard deviations were in the range of 1.0%—10.3%（n=3）.