Applied Metabolomics Research Group, Hospital Del Mar Research Institute, Barcelona, Spain; Environmental and Public Health Analytical Chemistry, Research Institute for Pesticides and Water (IUPA), Univ. Jaume I, Castelló, Spain.
Applied Metabolomics Research Group, Hospital Del Mar Research Institute, Barcelona, Spain.
Anal Chim Acta. 2024 Dec 1;1331:343313. doi: 10.1016/j.aca.2024.343313. Epub 2024 Oct 9.
Estradiol (E2) is a female sex hormone involved in several biological processes. Although E2 levels are commonly measured in blood samples, the use of non-invasive techniques (e.g. determination of salivary E2) would allow for the collection of repeated samples and the inclusion of a greater number of participants. Immunoassay-based techniques to measure salivary E2 failed to accurately mirror the variations observed in the plasmatic concentrations of E2 during the menstrual cycle probably due to the high sensitivity required (in the sub-pg/mL range). Therefore, sensitive and rugged analytical methods for the determination of salivary E2 are required. For this, we developed and validated an analytical methodology for the accurate determination of salivary E2.
The method is based on chemical derivatization with 1,2-dimethyl-1H-imidazole-5-sulphonyl chloride and liquid chromatography-tandem mass spectrometry analysis by summing highly-specific SRM transitions. This strategy allowed for increasing the sensitivity of the method. The validation of the method showed an accurate and precise quantification of E2 in 1 mL of saliva even at 250 fg/mL (97 % accuracy and 15 % RSD intra-day, and 104 % accuracy and 18 % RSD inter-day). In order to evaluate its efficacy, we analysed saliva samples from 5 healthy female volunteers collected during a whole menstrual cycle. Our analyses showed that the variations in the concentration of E2 in the measured samples mirrored those expected during a complete menstrual cycle. Additionally, we validated the suitability of our method for determining salivary E2 levels during pregnancy.
To the best of our knowledge, this is the first method that allows to precisely and accurately measuring E2 in saliva samples along the whole menstrual cycle of healthy females. It is also suitable for the determination of estradiol during pregnancy. Its high sensitivity makes this strategy ideal for the evaluation of the role of hormone production in women's health.
雌二醇（E2）是一种参与多种生物学过程的女性性激素。尽管 E2 水平通常在血液样本中进行测量，但使用非侵入性技术（例如唾液 E2 的测定）可以采集重复样本并纳入更多参与者。基于免疫测定的技术来测量唾液 E2 未能准确反映月经周期中观察到的血浆 E2 浓度的变化，可能是由于所需的高灵敏度（在亚 pg/mL 范围内）。因此，需要用于测定唾液 E2 的灵敏且坚固的分析方法。为此，我们开发并验证了一种用于准确测定唾液 E2 的分析方法。
该方法基于与 1,2-二甲基-1H-咪唑-5-磺酰氯的化学衍生化，通过总结高度特异性的 SRM 转换进行液相色谱-串联质谱分析。这种策略提高了方法的灵敏度。方法验证表明，即使在 250 fg/mL 时，也可以准确而精确地定量 1 mL 唾液中的 E2（97%的准确度和 15%的日内 RSD，以及 104%的准确度和 18%的日间 RSD）。为了评估其功效，我们分析了 5 名健康女性志愿者在整个月经周期中采集的唾液样本。我们的分析表明，测量样本中 E2 浓度的变化反映了整个月经周期中预期的变化。此外，我们验证了我们的方法在确定妊娠期间唾液 E2 水平方面的适用性。
据我们所知，这是第一个可以精确、准确地测量健康女性整个月经周期中唾液 E2 水平的方法。它也适用于怀孕期间雌二醇的测定。其高灵敏度使其成为评估女性健康中激素产生作用的理想选择。
