Socas-Rodríguez Bárbara, Lanková Darina, Urbancová Kateřina, Krtková Veronika, Hernández-Borges Javier, Rodríguez-Delgado Miguel Ángel, Pulkrabová Jana, Hajšlová Jana
Departamento de Química, Unidad Departamental de Química Analítica, Facultad de Ciencias, Universidad de La Laguna (ULL), Avenida Astrofísico Francisco Sánchez s/n°, 38206, San Cristóbal de La Laguna, Tenerife, Spain.
Faculty of Food and Biochemical Technology, Department of Food Analysis and Nutrition, University of Chemistry and Technology, Prague, Technicka 3, 166 28, Prague, Czech Republic.
Anal Bioanal Chem. 2017 Jul;409(18):4467-4477. doi: 10.1007/s00216-017-0391-x. Epub 2017 Jun 6.
Within this study, a new method enabling monitoring of various estrogenic substances potentially occurring in milk and dairy products was proposed. Groups of compounds fairly differing in physico-chemical properties and biological activity were analyzed: four natural estrogens, four synthetic estrogens, five mycoestrogens, and nine phytoestrogens. Since they may pass into milk mainly in glucuronated and sulfated forms, an enzymatic hydrolysis was involved prior to the extraction based on the QuEChERS methodology. For the purification of the organic extract, a dispersive solid-phase extraction (d-SPE) with sorbent C18 was applied. The final analysis was performed by ultra-high-performance liquid chromatography (UHPLC) coupled with triple quadrupole tandem mass spectrometry (MS/MS). Method recovery ranged from 70 to 120% with a relative standard deviation (RSD) value lower than 20% and limits of quantification (LOQs) in the range of 0.02-0.60 μg/L (0.2-6.0 μg/kg dry weight) and 0.02-0.90 μg/kg (0.2-6.0 μg/kg dry weight) for milk and yogurt, respectively. The new procedure was applied for the investigation of estrogenic compounds in 11 milk samples and 13 yogurt samples from a Czech retail market. Mainly phytoestrogens were found in the studied samples. The most abundant compounds were equol and enterolactone representing 40-90% of all estrogens. The total content of phytoestrogens (free and bound) was in the range of 149-3870 μg/kg dry weight. This amount is approximately 20 times higher compared to non-bound estrogens.
在本研究中，提出了一种能够监测牛奶和乳制品中可能出现的各种雌激素物质的新方法。分析了物理化学性质和生物活性差异较大的几类化合物：四种天然雌激素、四种合成雌激素、五种霉菌雌激素和九种植物雌激素。由于它们可能主要以葡萄糖醛酸苷化和硫酸化形式进入牛奶，因此在基于QuEChERS方法进行提取之前进行了酶水解。为了纯化有机提取物，采用了以C18为吸附剂的分散固相萃取（d-SPE）。最终分析通过超高效液相色谱（UHPLC）与三重四极杆串联质谱（MS/MS）联用进行。方法回收率在70%至120%之间，相对标准偏差（RSD）值低于20%，牛奶和酸奶的定量限（LOQ）分别在0.02 - 0.60 μg/L（0.2 - 6.0 μg/kg干重）和0.02 - 0.90 μg/kg（0.2 - 6.0 μg/kg干重）范围内。该新方法用于调查捷克零售市场上的11份牛奶样品和13份酸奶样品中的雌激素化合物。在所研究的样品中主要发现了植物雌激素。含量最高的化合物是雌马酚和肠内酯，占所有雌激素的40% - 90%。植物雌激素（游离和结合形式）的总含量在149 - 3870 μg/kg干重范围内。这一含量比未结合的雌激素大约高20倍。
