AIM: To identify the chemical constituents in Cuscuta Chinensis. METHODS: A High-performance liquid chromatography (HPLC) method combined with quadrupole-time-of-flight-mass spectrometry (QTOF-MS) has been developed for precise separation and structural identification of components in Cuscuta Chinensis. Mass spectrometry was performed in reflective time-of-flight using electron spraying ionizat...

We established a method to determine the glycosyl linkage structure by a combination of Smith degradation and liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (LC-ESI-Q-TOF-MS) and tandem MS (MS/MS). To assign the sugar linkage of N-glycoprotein, we employed a typical ribonuclease B containing oligosaccharides (Man5-9GlcNAc2). Tryptic digestion of ribonu...

Food adulteration and mislabeling may pose potential health risks and trust issues to consumers, particularly for high-valued wine products. The current analytical methods and anticounterfeit labeling techniques are insufficient to determine the identity and point of origins for these products. This application note describes a metabolomic profiling method to trace the origins of wine products ...

The analysis of tandem mass (MS/MS) data to identify and quantify proteins is hampered by the heterogeneity of file formats at the raw spectral data, peptide identification, and protein identification levels. Different mass spectrometers output their raw spectral data in a variety of proprietary formats, and alternative methods that assign peptides to MS/MS spectra and infer protein identificat...

Most proteins are post-translationally modified and the characterization of modified peptides in complex mixtures generated by enzymatic digestion of multiple proteins remains a major analytical challenge. We describe an integrated LC-MS workflow implemented on a hybrid quadrupole time-of-flight (Q-ToF) instrument to detect modified peptides in a complex peptide sample and establish the nature ...

Fomesafen (FSA) is widely used in soybean fields for weed control. However, the persisting characteristics of FSA agricultural soil or water may become a hidden danger causing environmental pollution and phytotoxicity to succession crops. In this study, growth physiological responses rice were investigated. It was found that seedlings obviously inhibited by exposure especially at over 0.1 mg L?...

Cyclooxygenase is involved in the biosynthesis and function of prostaglandins. It is a glycoprotein located in the endoplasmic reticulum and in the nuclear envelope, and it has been found to have two isoforms termed COX-1 and COX-2. This paper reports on the glycosylation site analysis of recombinant COX-2 using matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spect...

Evidence suggests that high-density lipoprotein (HDL) components distinct from cholesterol, such as sphingosine-1-phosphate (S1P), may account for the anti-atherothrombotic effects attributed to this lipoprotein. The current method for the determination of plasma levels of S1P as well as levels associated with HDL particles is still cumbersome an assay method to be worldwide practical. Recently...

An ultra-performance convergence chromatography (UPC(2)) system coupled with quadrupole time-of-flight mass spectrometry (Q-TOF-MS) was successfully utilised to analyse triacylglycerols and diacylglycerols in cow milk fat. This novel approach obtained an improved resolution of triacylglycerols in comparison to previously reported chromatographic methods combined with MS detector in a shorter an...

This application note presents three complementary LC/Q-TOF workflows designed to provide comprehensive analysis of micropollutants in surface waters: • Targeted quantification • Suspect screening with and without MS/MS spectra • Unknown compound identification The first two workflows rely on the Agilent All Ions MS/MS accurate mass capabilities of the Agilent LC/Q-TOF system, Agilent MassHunte...