Department of Food Science and Technology, CEBAS-CSIC, Espinardo (Murcia), Spain.
Rapid Commun Mass Spectrom. 2012 May 30;26(10):1249-57. doi: 10.1002/rcm.6224.
Isoprostanes (IsoPs) are a series of prostaglandin (PG)-like compounds formed non-enzymatically through free-radical-induced peroxidation of arachidonic acid. They are considered as 'gold-standard' biomarkers for oxidative stress, in general, and lipid peroxidation, in particular.
A new qualitative and quantitative analytical method for the determination of 13 eicosanoids in human urine using solid-phase extraction (SPE) and ultra-pressure liquid chromatography coupled to tandem mass spectrometry (UPLC/MS/MS) has been developed. The SPE was optimized by comparison of the extraction efficiency and recoveries of three distinct cartridges: Strata X-AW, C18 Sep-Pak, and Oasis HLB. The UPLC/MS/MS approach in the multiple reaction monitoring (MRM) mode was developed using negative electrospray ionization (ESI).
The validated method provides a high-throughput assay with an adequate linearity from 0.16 to 330 ng mL(-1). The limit of detection (LOD) and limit of quantification (LOQ) for each analyte showed low intervals (0.021-0.64 ng mL(-1) and 0.042-1.28 ng mL(-1), respectively). Urinary IsoPs were determined in 24 healthy volunteers and ranged from 685 to 3480 ng 24 h(-1) and from 864 to 7511 ng 24 h(-1) in urine from women and men, respectively.
This analytical method could constitute a useful tool for the determination of oxidative stress biomarkers in clinical studies in which IsoPs may evidence early pathological conditions, as suggested by the determination of the baseline IsoPs content in human urine, since it improves upon the detection capacity of previously described methods. The quantity of IsoPs excreted in urine was higher than that found in previous reports due to the total hydrolysis of the conjugated forms.
异前列腺素（IsoPs）是一类通过花生四烯酸自由基诱导的过氧化作用非酶促形成的前列腺素（PG）样化合物。它们通常被认为是氧化应激和脂质过氧化的“金标准”生物标志物。
开发了一种使用固相萃取（SPE）和超高压液相色谱串联质谱（UPLC/MS/MS）测定人尿液中 13 种类二十烷酸的定性和定量分析方法。通过比较三种不同的提取效率和回收率，对 SPE 进行了优化：Strata X-AW、C18 Sep-Pak 和 Oasis HLB。UPLC/MS/MS 方法在多反应监测（MRM）模式下采用负电喷雾电离（ESI）进行开发。
验证后的方法提供了一种高通量检测方法，其线性范围从 0.16 到 330 ng mL(-1)。每个分析物的检测限（LOD）和定量限（LOQ）都显示出较低的范围（0.021-0.64 ng mL(-1) 和 0.042-1.28 ng mL(-1)）。在 24 名健康志愿者中测定了尿液中的 IsoPs，女性尿液中的范围为 685 至 3480 ng 24 h(-1)，男性尿液中的范围为 864 至 7511 ng 24 h(-1)。
该分析方法可作为临床研究中测定氧化应激生物标志物的有用工具，因为 IsoPs 可能在早期病理条件下表现出早期病变，正如通过测定人尿液中 IsoPs 的基础含量所表明的那样，因为它提高了以前描述的方法的检测能力。由于共轭形式的完全水解，尿液中排泄的 IsoPs 量高于以前的报道。
