Chromatographic analysis of Polygalae Radix by online hyphenating pressurized liquid extraction

Abstract

Practicing “green analytical chemistry” is of great importance when profiling the chemical composition of complex matrices. Herein, a novel hybrid analytical platform was developed for direct chemical analysis of complex matrices by online hyphenating pressurized warm water extraction followed by turbulent flow chromatography coupled with high performance liquid chromatography-tandem mass spectrometry (PWWE-TFC-LC-MS/MS). Two parallel hollow guard columns acted as extraction vessels connected to a long narrow polyether ether ketone tube, while warm water served as extraction solvent and was delivered at a flow rate of 2.5 mL/min to generate considerable back pressure at either vessel. A column oven heated both the solvent and crude materials. A TFC column, which is advantageous for the comprehensive trapping of small molecular substances from fluids under turbulent flow conditions, was employed to transfer analytes from the PWWE module to LC-MS/MS. Two electronic valves alternated each vessel between extraction and elution phases. As a proof-of-concept, a famous herbal medicine for the treatment of neurodegenerative disorders, namely Polygalae Radix, was selected for the qualitative and quantitative analyses. The results suggest that the hybrid platform is advantageous in terms of decreasing time, material, and solvent consumption and in its automation, versatility, and environmental friendliness.

Full collision energy ramp‐MS2 spectral features of natural esters: Salvianolic acid A as a case

“…This versatile tool empirically considers that OCEs are positively, linearly correlated with HR‐ m/z values of the precursor ions when precursor ions are compared with identical charging states. After the previously obtained OCEs are involved, such as phenylethanoid glycosides, 6,11 chlorogenic acid derivatives, 7 and oligosaccharide esters, 12 as expected, positive correlations occur approximately between OCEs and HR‐ m/z values of quasi‐molecular ions when the identical ion type, for example, y − ions, is compared.…”

“…SA generates greater MS/MS spectra when negative ionization polarity is deployed. Figure 1A shows the MS 2 spectrum of the deprotonated molecular ion (m/z 493.1169, OCEs are involved, such as phenylethanoid glycosides, 6,11 chlorogenic acid derivatives, 7 and oligosaccharide esters, 12 as expected, positive correlations occur approximately between OCEs and HR-m/z values of quasi-molecular ions when the identical ion type, for example, y À ions, is compared.…”

“…In the case of peptides, those y ‐type ions usually dominate the MS 2 spectra, and b + ions serve in complementary roles, while the other ions are seldom observed in collision‐induced dissociation (CID) mode. After we reanalyzed the MS 2 spectra of those esters assayed in our group, phenylethanoid glycosides, 6,11 chlorogenic acid derivatives, 7 and oligosaccharide esters, 12 and collected data from available databases such as ChemSpider, MyCompoundID, and HMDB, we conclude that y − and b − ions usually serve as the most abundant fragment ion species for most esters, and a − , c − , and z − ions frequently have inferior intensities. x − ion is absent in most cases.…”

Quality standard of traditional Chinese medicines: comparison between European Pharmacopoeia and Chinese Pharmacopoeia and recent advances

“…A turbulent flow chromatography column was incorporated to trap the small molecular components and transfer the analytes to HPLC. This system was successfully applied to the analysis of Polygalae Radix [36] and Cistanches Herba [37,38].…”

Direct Flavonoid-Focused Chemical Comparison among Three Epimedium Plants by Online Liquid Extraction–High Performance Liquid Chromatography–Tandem Mass Spectrometry

“…It is still challenging to achieve efficient extraction due to the prerequisite of compatibility between the extraction solvent and the LC mobile phase. Fortunately, a smart online liquid extraction (OLE) module has been configured allowing direct analysis of solid matrices, where aqueous acetonitrile and even water, are usually employed as the extraction solvents because the pressurized warm solvent exhibits lower viscosity and polarity and is able to efficiently extract less polar compounds [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. The hyphenation of this OLE module with conventional LC–MS might offer the desired opportunity for direct analysis of HMs.…”