An automatic versatile system integrating solid-phase extraction with ultra-high performance liquid chromatography-tandem mass spectrometry using a dual-dilution strategy for direct analysis of auxins in plant extracts.

An automatic versatile system which integrated solid phase extraction (SPE) with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed. Diverse commercial SPE columns can be used under an ambient pressure in this online system realized by a dual-dilution strategy. The first dilution enabled the direct injection of complex samples with minimal pretreatment, and the second dilution realized direct introduction of large volume of strong eluent into the UHPLC column without causing peak broadening or distortion. In addition, a post-column compensation mode was also designed for the matrix-effects evaluation. The features of the online system were systematically investigated, including the dilution effect, the capture of desorption solution, the column-head stacking effect and the system recovery. Compared with the offline UHPLC system, this online system showed significant advantages such as larger injection volume, higher sensitivity, shorter analysis time and better repeatability. The feasibility of the system was demonstrated by the direct analysis of three auxins from different plant tissues, including leaves of Dracaena sanderiana, buds and petals of Bauhinia. Under the optimized conditions, the whole analysis procedure took only 7min. All the correlation coefficients were greater than 0.9987, the limits of detection and the limits of quantitation were in the range of 0.560-0.800ng/g and 1.80-2.60ng/g, respectively. The recoveries of the real samples ranged from 61.0 to 117%. Finally, the post-column compensation mode was applied and no matrix-effects were observed under the analysis conditions. The automatic versatile system was rapid, sensitive and reliable. We expect this system could be extended to other target analytes in complex samples utilizing diverse SPE columns.

Global detection and identification of components from crude and processed traditional Chinese medicine by liquid chromatography connected with hybrid ion trap and time-of-flight-mass spectrometry.

We herein present a chemical profiling method to efficiently process the information acquired by ultra fast liquid chromatography (UFLC)-electrospray ionization source in combination with hybrid ion trap and high-resolution time-of-flight mass spectrometry (UFLC-(ESI)-IT-TOF/MS), facilitating the structural determination of serial components contained in crude or processed traditional Chinese medicine (TCM). Under the optimized UFLC and IT-TOF-MS(n) conditions, over 39 compounds were separated and detected in crude or processed Fructus corni within 25 min. The components were identified by comparing the mass spectra and retention time with reference compounds, or tentatively assigned by elucidating low-energy collision-induced dissociation (CID) fragment ions and matching empirical molecular formula with that of the published compounds. Several factors in the processing procedure were examined. The experimental results demonstrate that the chemical reactions that occurred in the processing procedure can be used to elucidate the processed mechanism of F. corni, which is regularly affected by the processing conditions. This study provides a novel approach and methodology to identify the complicated components from various complex mixtures such as crude TCM, processed TCM, and biological samples. It can be used as a valid analytical method for further understanding the processing mechanism of TCM, along with the intrinsic quality control of TCM and its processed product.