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Searching for the mechanisms of the polycystic ovary syndrome (PCOS) pathophysiology has become a crucial aspect of research performed in the last decades. However, the pathogenesis of this complex and heterogeneous endocrinopathy remains unknown. Thus, there is a need to investigate the metabolic pathways, which could be involved in the pathophysiology of PCOS and to find the metabolic markers of this disorder. The application of metabolomics gives a promising insight into the research on PCOS. It is a valuable and rapidly expanding tool, enabling the discovery of novel metabolites, which may be the potential biomarkers of several metabolic and endocrine disorders. The utilization of this approach could also improve the process of diagnosis and therefore, make treatment more effective. This review article aims to summarize actual and meaningful metabolomic studies in PCOS and point to the potential biomarkers detected in serum, urine, and follicular fluid of the affected women.

Two types of chemically bonded phases for high-performance liquid chromatography (HPLC) have been prepared:  a conventional C18 and AP (N-acylaminopropylsilica), a novel one that contains specific interaction sites localized in the hydrophobic chain. Surface properties of stationary phases, before and after chemical modification, have been characterized by several physicochemical techniques, such as porosimetry, ICP atomic emission spectroscopy, elemental analysis, solid state CP/MAS NMR, and chromatography. For the studies of the reversed-phase HPLC retention mechanism under hydroorganic conditions, a test series of structurally diverse solutes has been selected. Sets of retention parameters and structural descriptors of the test solutes were subjected to multiparameter regression analysis. The quantitative structure−retention relationships derived demonstrated the typical reversed-phase partition mechanism to predominate in the separation on the C18 phases but not on the AP phases. The AP phases were demonstrated to provide significant input to retention due to the structurally specific dipole−dipole and charge transfer interactions with the solutes. The proposed AP phases for HPLC possess distinctive and interesting retentive properties, and chemometric analysis of retention data of appropriately designed series of test solutes appears to be a convenient, objective, and quantitative method to prove a new phase specificity.

pH gradient HPLC is reported, which is a new original mode of reversed-phase high-performance liquid chromatography applicable to ionogenic analytes. The method consists of programmed increase during the chromatographic run of the eluting strength of the mobile phase with respect to the acid/base analytes separated. Unlike the well-established conventional gradient HPLC, where the eluting power of the mobile phase is increased with time due to the increasing content of organic modifier, in the pH gradient HPLC that is realized by linearly increasing (in the case of acids) or decreasing (in the case of bases) the pH of the eluent of a fixed organic modifier content, thus providing functional increase in the degree of analyte dissociation and, hence, a decrease in its retention. The pH gradient mode has typical features of gradient HPLC, such as reduced peak width and minimized peak-tailing due to peak compression, which is especially advantageous in the case of organic base analytes. It may be of special value for separation of those analytes which are susceptible to the higher concentrations of organic solvents, as many bioanalytes are. A theory of the pH gradient HPLC has been elaborated, and its full mathematical formalistic is presented step by step in a comprehensive manner. Although fundamental relationships at the basis of pH gradient HPLC are more complex than in the case of the organic gradient variant, the resulting mathematical model is easily manageable. Its applicability to predict changes in retention and separation of test mixtures of analytes accompanying the changes in chromatographic conditions has been demonstrated experimentally in both gradient and isocratic HPLC. The proposed model supplies a rational basis for modifications of eluent pH aimed at optimization of separations and for convenient assessment of chromatographically relevant physicochemical parameters of analytes, such as pK(a).

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