[Determination of Nucleosides and Nucleobases in Natural, Cultured and Tissue Culture Anoectochilus roxburghii Using LC-MS].

OBJECTIVE: To establish a method for simultaneous determination of nucleosides and nucleobases in natural, cultured and tissue culture Anoectochilus roxburghii by high performance liquid chromatography-electrospray ionization/ion trap mass spectrometry (HPLC-ESI/MS). METHODS: The separation was performed on a Welch Ultimate XB-C18 column (250 mm x 4.6 mm,5 µm). 20 mmol/L ammonium acetate solution and methanol were adopted as the mobile phase with gradient elution. The flow rate was 1.0 mL/min. The injection volume was 20 µL. The column temperature and UV wavelength were set at 30 degrees C and 260 nm, respectively. RESULTS: Cytosine, uracil, cytidine, uridine, hypoxanthine, adenine, inosine, guanosine,fl-thymidine and adenosine were identified in natural, cultured and tissue culture Anoectochilus roxburghii. The total content of nucleosides and nucleotides in Anoectochilus roxburghii were 1.6639, 1.8568 and 2.2013 mg/g,respectively. CONCLUSION: The contents of nucleosides and nucleobases in herb are affected by its growth pattern. The total content of nucleosides and nucleotides was tissue culture herb > cultured herb > natural herb. This investigation would provide the theoretic basis for quality standards and applications of Anoectochilus roxburghii in clinical research.

Simultaneous determination of twelve paralytic shellfish poisoning toxins in bivalve molluscs by UPLC-MS/MS and its applications to a food poisoning incident.

In this study, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was originally developed for simultaneously quantitative analysis of twelve paralytic shellfish poisoning toxins, referring to STX, NEO, dcSTX, GTX1, GTX2, GTX3, GTX4, GTX5, C1, C2, dcGTX2, and dcGTX3 in bivalve molluscs. Chromatographic separations were performed on a TSK-Gel Amide-80 column (5 µm, 2.0 × 150 mm, Tosoh Corporation) by gradient elution with 2 mmol L-1 ammonium formate solution-acetonitrile (containing 0.1% formic acid) as mobile phases. The samples were pretreated by extraction with acetonitrile-water (80:20, v/v; containing 0.1% formic acid), followed by cleaning up using an Oasis HLB extraction cartridge (500 mg/6 mL). The present method showed good linearity (r2 > 0.99) with the limits of detection (LODs) and limits of quantification (LOQs) ranged from 1.03 to 10.65 µg/kg and 3.43-35.46 µg/kg, respectively for these toxins. Owing to its sensitivity and rapid properties, the presented method was applied to the determination of PSP toxins in bivalve molluscs involved in a food poisoning incident occurred in Zhangzhou, China, in June 2017.