Mass Spectrometric Approaches for the Analysis of Phytosterols in Biological Samples

Abstract

Plant sterols (phytosterols) are important structural components of plant cellular membranes, and they play a major role during development and metabolism. They have health-associated benefits, especially in lowering blood cholesterol levels. Because of their many health claims, there is a growing interest in their analysis. Although various analytical strategies have been employed in analyzing phytosterols, chromatography linked to mass spectrometry (MS) is superior due to its sensitivity. Furthermore, specificity and selectivity are enhanced by utilizing tandem mass spectrometry (MS/MS). This article reviews the various mass spectrometric strategies used for the analysis of phytosterols. It highlights the applications and limitations associated with each MS strategy in various sample matrixes such as plant, human, animal, food, and dietary supplements. GC-MS was historically the method of choice for analysis; however, the derivatization step rendered it tedious and time-consuming. On the other hand, liquid chromatography coupled to MS (LC-MS) simplifies the analysis. Many ionization techniques have been used, namely, electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photoionization (APPI). APCI showed superiority in terms of ion intensity and consistency in ion formation, primarily forming [M + H - HO] ions rather than [M + H]. In addition, matrix assisted laser desorption ionization (MALDI) as well as ambient mass spectrometry such as direct analysis in real time (DART) have also been evaluated.

UPLC-MS/MS Based Identification of Dietary Steryl Glucosides by Investigation of Corresponding Free Sterols

“…ESI was used to ionize all sterols within this study, as it was previously shown to be superior to APCI with regard to ion intensity in case of SG, when the intact molecule being investigated included the sugar moiety (Oppliger et al, 2014 ). Therefore, ESI was also applied to FS to ensure consecutive comparability with SG spectra even though APCI is the method of choice for FS because of higher ion intensity and consistency in ion formation (Baila-Rueda et al, 2013 ; Gachumi and El-Aneed, 2017 ).…”

Influence of acid hydrolysis, saponification and sample clean‐up on the measurement of phytosterols in dairy cattle feed using GC–MS and GC with flame ionization detection

“…Quantification of the phytosterols was achieved using FID with appropriate reference standards and 5β‐cholestan‐3α‐ol as the internal standard to create traditional calibration curves. Confirmation of sterol identification was achieved using MS . The linearity dynamic range (LDR) for the majority of individual phytosterols was found to be 0.1 to 200 mg/L, except for brassicasterol and campestanol where the LDR was 0.1 to 100 mg/L due to the limited availability of reference standards.…”

Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance

“…While no single sterol species seems to dominate the plant sterol profile, sitosterol, campesterol, and stigmasterol are the most common ones followed by brassicasterol, gramisterol, obtusifoliol, cycloartenol, amyrin, stigmastanol, and sitostanol. 169 Sitosterol and campesterol are also noteworthy, as they constitute 90 mass % of phytosterols (plant sterols) in the human diet. 170 In Arabidopsis thaliana , of all sterols, 64 mol % are sitosterols, 11 mol % are campesterols, 6 mol % are stigmasterols, 3 mol % are isofucosterols, and 2 mol % are brassicasterols.…”