An ultra high performance liquid chromatography coupled with a triple quadrupole mass detection and electrospray ionization mass spectrometry method has been established for the simultaneous determination of the 14 nucleosides and nucleobases, 24 amino acids and two main alkaloids in mulberry leaf. In this method, a complicated mobile phase, the flow rate of which was 0.4 mL/min, was applied to the gradient elution, which provided a satisfied separation of the 40 compounds. The present method was validated, and sufficient reproducibility and accuracy were obtained for the quantitative measurement of the 40 compounds. The method was subsequently applied to ten mulberry leaves and the results showed that almost all of these samples were rich in nucleosides, nucleobases, amino acids, and alkaloids. The proposed method, which is convenient and economical, could serve as a prerequisite for the quality control of mulberry leaf herbs and be applied analogously to other Chinese medicines.

To evaluate the nutritional and functional value of Sipunculus nudus, a rapid, simple and sensitive analytical method was developed using ultra-high performance liquid chromatography coupled with a triple quadrupole mass detection in multiple-reaction monitoring mode for the simultaneous quantitative determination of 25 free amino acids and 16 nucleosides and nucleobases in S. nudus within 20 min, which was confirmed to be reproducible and accurate. The limits of detection (LODs) and quantification (LOQs) were between 0.003-0.229 μg/mL and 0.008-0.763 μg/mL for the 41 analytes, respectively. The established method was applied to analyze 19 batches of S. nudus samples from four habitats with two different processing methods. The results showed that S. nudus contained a variety of free amino acids, nucleosides and nucleobases in sufficient quantity and reasonable proportion. They also demonstrated that the contents of these compounds in different parts of S. nudus were significantly discriminating, which were in the order: (highest) coelomic fluid > body wall > intestine (lowest). The method is simple and accurate, and could serve as a technical support for establishing quality control of S. nudus and other functional seafoods. Moreover, the research results also laid foundation for further exploitation and development of S. nudus.

Branched fatty acid ester of hydroxy fatty acid (FAHFA) is a class of natural lipid with important biological functions. In this study, we first profiled natural-origin FAHFAs in different teas using the chemical labeling-assisted liquid chromatography-mass spectrometry method. Consequently, we observed rich molecular diversity of FAHFAs with multiple regioisomers in teas. Additionally, the FAHFA contents had a positive relationship with the tea fermentation degree and a negative relationship with homologous fatty acids. Moreover, the highly accumulated FAHFAs (e.g., 3-MAHMA) in some postfermented teas (e.g., Fu brick tea) were also basically interpreted with regiospecificity of FAHFAs in both teas and fungus. This study revealed that tea is a rich natural source of FAHFAs, and some abundant FAHFAs might be the functional molecules accounting for the antidiabetic function of teas.

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