Rapid Screening of 34 Emerging Contaminants in Surface Water by UHPLC-Q-TOF-MS.

OBJECTIVES: To establish a rapid screening method for 34 emerging contaminants in surface water by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry (UHPLC-Q-TOF-MS). METHODS: The pretreatment conditions of solid phase extraction (SPE) were optimized by orthogonal experimental design and the surface water samples were concentrated and extracted by Oasis® HLB and Oasis® MCX SPE columns in series. The extracts were separated by Kinetex® EVO C18 column, with gradient elution of 0.1% formic acid aqueous solution and 0.1% formic acid methanol solution. Q-TOF-MS 'fullscan' and 'targeted MS/MS' modes were used to detect 34 emerging contaminants and to establish a database with 34 emerging contaminants precursor ion, product ion and retention times. RESULTS: The 34 emerging contaminants exhibited good linearity in the concentration range respectively and the correlation coefficients (r) were higher than 0.97. The limit of detection was 0.2-10 ng/L and the recoveries were 81.2%-119.2%. The intra-day precision was 0.78%-18.70%. The method was applied to analyze multiple surface water samples and 6 emerging contaminants were detected, with a concentration range of 1.93-157.71 ng/L. CONCLUSIONS: The method is simple and rapid for screening various emerging contaminants at the trace level in surface water.

Dihydromyricetin exerted its vasoconstrictive effects by increasing intracellular Ca~(2+) in isolated canine carotid artery / 中国药理学通报

Aim To investigate the effect of dihydromyricetin on canine carotid artery and the underlying mechanism.Methods The in vitro isometric tension measurement technique was employed to investigate the effect of dihydromyricetin on canine carotid artery rings.Laser scanning confocal microscope technique was used to measure the dynamic change of intracellular calcium concentration in single VSMC.Results Dihydromyricetin(1～300 ?mol?L-1)caused a concentration-dependent contraction of both endothelium-intact and endothelium-denuded rings.This constrictive effect was attenuated in Ca2+-free solution(P