A high-efficiency quantitation method for fatty aldehyde based on chemical isotope-tagged derivatisation

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.