Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Química, Universidad de La Laguna (ULL), Avenida Astrofísico Francisco Sánchez s/n°, 38206 La Laguna (Tenerife), Spain.
J Chromatogr A. 2013 Oct 25;1313:175-84. doi: 10.1016/j.chroma.2013.05.028. Epub 2013 May 20.
In this work, a group of nine estrogens, four of them being natural (estriol, 17β-estradiol, 17α-estradiol and estrone), four being synthetic (17α-ethynylestradiol, diethylstibestrol, dienestrol and hexestrol) and one metabolite (2-hydroxyestradiol) have been extracted and preconcentrated from milk samples with different fat content (whole, semi-skimmed and skimmed). After protein precipitation with acetonitrile containing acetic acid, evaporation of the supernatant and reconstitution of the residue in water, hollow-fiber liquid-phase microextraction (HF-LPME) using 1-octanol as extraction solvent was applied to further preconcentrate the analytes. Separation, determination and quantification were achieved by high-performance liquid chromatography coupled to a diode array detector and a fluorescence detector set in series. Deproteinization conditions, as well as parameters affecting the extraction efficiency in HF-LPME (pH of the sample, ionic strength, extraction time, stirring speed, temperature and desorption conditions) were investigated and optimized. Calibration, precision and accuracy studies were carried out to validate the methodology in different types of milk providing LODs in the low μg/L range.
在这项工作中，从不同脂肪含量（全脂、半脱脂和脱脂）的牛奶样品中提取并预浓缩了九种雌激素，其中四种为天然雌激素（雌三醇、17β-雌二醇、17α-雌二醇和雌酮），四种为合成雌激素（17α-乙炔基雌二醇、己烯雌酚、双烯雌酚和己烷雌酚），一种为代谢物（2-羟基雌二醇）。用含乙酸的乙腈沉淀蛋白质后，蒸发上清液，将残留物重新溶于水中，然后用 1-辛醇作为萃取溶剂，采用中空纤维液相微萃取（HF-LPME）进一步预浓缩分析物。通过高效液相色谱与二极管阵列检测器和串联荧光检测器进行分离、测定和定量。考察并优化了蛋白质沉淀条件以及影响 HF-LPME 萃取效率的参数（样品 pH 值、离子强度、萃取时间、搅拌速度、温度和洗脱条件）。在不同类型的牛奶中进行了校准、精密度和准确度研究，以验证该方法在低μg/L 范围内的检测限。
