Ultra-performance liquid chromatography-tandem mass spectrometry assay for determination of plasma nomegestrol acetate and estradiol in healthy postmenopausal women

Liquid chromatography-mass spectrometry applications for quantification of endogenous sex hormones

Liquid chromatography, coupled with tandem mass spectrometry, presents a powerful tool for the quantification of the sex steroid hormones 17-β estradiol, progesterone and testosterone from biological matrices. The importance of accurate quantification with these hormones, even at endogenous levels, has evolved with our understanding of the role these regulators play in human development, fertility and disease risk and manifestation. Routine monitoring of these analytes can be accomplished by immunoassay techniques, which face limitations on specificity and sensitivity, or using gas chromatography-mass spectrometry. LC-MS/MS is growing in capability and acceptance for clinically relevant quantification of sex steroid hormones in biological matrices and is able to overcome many of the limitations of immunoassays. Analyte specificity has improved through the use of novel derivatizing agents, and sensitivity has been refined through the use of high-resolution chromatography and mass spectrometric technology. This review highlights these innovations, among others, in LC-MS/MS steroid hormone analysis captured in the literature over the last decade.

Development of an innovative phytosterol derivatization method to improve the HPLC-DAD analysis and the ESI-MS detection of plant sterols/stanols

HPLC analyses of phytosterols are associated with the issues of sensitivity due to their high lipophilicity and their lack of chromophore. These problems could be solved through chemical modifications of plant sterols/stanols structures. Therefore, the present study aims to develop a new method for phytosterols derivatization. This method was performed using dansyl chloride (4 mg ml^-1) as derivatizing agent and different reaction parameters have been optimized. The highest yields of phytosterol derivatization were obtained with 4-dimethylaminopyridine (DMAP) as catalyst at a concentration of 8 mg ml^-1 and dichloromethane as reaction solvent. In addition, 40 ˚C was the best reaction temperature for 30 min as the best reaction time. This derivatization method presented a high reproducibility (%RSD = 1.2-2.7%) and a good linearity (R² = 0.9982-0.9999). The UV absorption intensities after derivatization showed a 23-fold increment for plant sterols and a 400-fold increment for plant stanols. Moreover, this derivatization method allowed the use of high and more selective wavelengths of detection and improved the chromatographic separation of phytosterols. Furthermore, the developed method allowed the ESI-MS ionization and analysis of phytosterols. This method can therefore contribute to the improvement of the HPLC analyses of plant sterols/stanols.