Fatty aldehydes are the end products of lipid peroxides and are involved in a wide range of cellular biological pathways, food quality and flavour. However, the quantitative methods of analysing fatty aldehydes are limited due to the neutral properties of the carbonyl group, and their hydrophilicity and instability. In this study, a comprehensive isotope-coded derivative, 5-(dimethylamino)-1-carbohydrazide-isoquinoline (DMAQ), was developed for sensitive and accurate quantitative analysis of fatty aldehydes. The derivatives can remarkably improve the ionisation efficiency and separation performance of aldehydes and minimise matrix effects. The limit of detection of derivatised aldehydes was as low as 0.09 ng/L. The intra-day and inter-day relative standard deviations were well below 5.24 % and 7.97 %, respectively. This new method was successfully applied in fatty aldehyde analysis of fresh meat under different post-harvest processes. These results demonstrated that isotope-coded DMAQ derivatisation provides a useful tool for quantifying fatty aldehydes in complex biological samples with high accuracy and precision.
Short-chain fatty acids (SCFAs) are major gut microbiota-derived metabolites, which can reshape the intestine and regulate gut immunity. The application of conventional GC methods has been hampered for quantifying low-concentrated SCFAs, such as in serum, saliva, and digesta of germ-free animals. Herein, we established a LC–MS method to quantify SCFAs after 5-(dimethylamino)-1-carbohydrazide-isoquinoline (DMAQ) derivatization. The DMAQ derivatization significantly enhanced the detection sensitivity and improved separation of SCFAs. 2-methylbutyric acid and 3-methylbutyric acid were separately quantitated. Moreover, the matrix effect was diminished using DMAQ-13C/15N-tagged SCFAs as internal standards. The established quantitation method was successfully applied in the analysis of plasma and cecum digesta collected from neonatal piglets, revealing that significant increases in biological SCFA contents in cecum digesta were closely related to the variation of gut microbial diversity. The established quantitation method is capable of sensitively and comprehensively quantifying SCFAs that may provide insights into underlying gut-microbiota functions.
危险品化学品经营许可证（带存储）