A novel, fast and sensitive supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) method for analysis of arachidonic acid metabolites.

The development of a rapid, sensitive and reliable method for the quantification of bioactive arachidonic acid metabolites (AA-metabolites) in biological samples is quite challenging due to the minute concentration, short half-life and their structural complexity arising from different isomers. In this study, a simple, fast and environmentally friendly supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) method was developed and validated for simultaneous measurement of five (PGD2, PGE2, PGF2α, 6KetoPGF1α and LTB4) AA-metabolites in biological samples. These analytes were extracted by protein precipitation followed by separation and quantification. The analysis was completed within 3 minutes. The matrix matched linear calibration ranged from 0.5-100 ng mL-1 (r2 ≥ 0.995), whilst, the limit of quantification of PGD2, PGE2, PGF2α, and LTB4 was 0.5 ng mL-1 and was 2.5 ng mL-1 for 6KetoPGF1α. The interday and intraday precisions of the method were less than 15% while the accuracy of most of the analytes varied between 83 and 109%. Finally, as a proof of concept, the method was successfully applied for the determination of eicosanoids in human samples, which expands the possibility to explore physiological states, disease phenotypes, and novel biomarkers.

A fast ultra performance supercritical fluid chromatography-tandem mass spectrometric method for profiling of targeted phytosterols.

Phytosterols are essential structural components of plant cell membranes and possess health-related benefits, including lowering blood cholesterol levels in humans. Numerous analytical methods are being used to profile plant and animal sterols. Chromatography hyphenated to tandem mass spectrometry, is a better option due to its specificity, selectivity, and sensitivity. An ultra-performance supercritical fluid chromatography hyphenated with atmospheric pressure chemical ionization (APCI) tandem mass spectrometric method was developed and evaluated for fingerprint analysis of seven phytosterols. Mass spectrometry fragmentation behavior was used for phytosterol identification, and multiple reaction monitoring scanning was utilized for phytosterol confirmation, where APCI outperformed superiority in terms of ion intensity, particularly in the production of [M + H-H2O]+ ions rather than [M + H]+ ions. The chromatographic conditions were thoroughly evaluated, and the ionization parameters were optimized as well. In a 3 min. run, the seven phytosterols were separated concurrently. The calibration and repeatability tests were conducted to check the instrument's performance, and the results indicated that all of the phytosterols tested had correlation coefficients (r2) greater than 0.9911 over the concentration range of 5-5000 ng/mL. The limit of quantification was below 20 ng/mL for all the tested analytes except for stigmasterol and campesterol. The partially validated method was applied for the evaluation of phytosterols in pure coconut oil and palm oil in order to demonstrate its applicability. Total sterols in coconut and palm oils were 126.77 ng/mL and 101.73 ng/mL, respectively. In comparison to earlier methods of phytosterol analysis, the novel method offers a far faster, more sensitive, and more selective analytical process.