Targeted Microchip Capillary Electrophoresis-Orbitrap Mass Spectrometry Metabolomics to Monitor Ovarian Cancer Progression

Analysis of Major Chemical Constituents in Jiuwei Decoction Based On Capillary Electrophoresis Coupled With Quadrupole Time-of-Flight Mass Spectrometry

An analytical method for identifying the chemical constituents in the Chinese herbal combination Jiuwei decoction was established using capillary electrophoresis coupled with quadrupole time-of-flight mass spectrometry. Nine herbs were extracted with a 60:40 (v/v) ethanol/water solution to prepare the Jiuwei decoction. Electrophoretic separation was carried out using a 50 µm i.d., 125 cm bare fused silica capillary at a constant temperature of 25°C for sample injection. The chemical composition was analyzed and identified in both positive and negative ion modes. In the positive separation mode, a separation voltage of 30 kV was applied, with a 1% aqueous formic acid solution serving as the background electrolyte (BGE), along with a 50:50 (v/v) methanol/water solution containing 0.1% formic acid as the sheath liquid. In the negative separation mode, a separation voltage of -30 kV was employed, utilizing a 50 mM ammonium acetate solution (pH 9.0) as the BGE, combined with a 50:50 (v/v) methanol/water solution containing 5 mM ammonium acetate as the sheath liquid. The MassHunter Qualitative Analysis software (version 10.0) was utilized to identify 52 compounds based on accurate mass, isotope abundance, isotopic patterns, and fragmentation information. The data were compared with the Agilent Personal Compound Database and Library of traditional Chinese medicine (TCM), as well as multiple online databases (TCMSP, ChemSpider, PubChem, PubMed, and Web of Science) and relevant literature. The fragmentation pathways of representative compounds were also characterized. This study identified the chemical composition of Jiuwei decoction, providing a molecular basis for further exploration of its pharmacological effects and presenting a robust methodology for the compositional analysis of complex TCM mixtures.

Microchip capillary electrophoresis-mass spectrometry for high-throughput simultaneous analysis of B-complex vitamins

B-complex vitamins are essential micronutrients that maintaining health, and provide (individually/simultaneously) many important biological actions in organism. Therefore, sensitive, reliable analytical method to determine B-complex vitamins simultaneously in actual samples is significant. Conventional analytical methods for vitamins analysis are usually labor-intensive, time-consuming and mostly do not allow the simultaneous determination. Few papers have been published on capillary electrophoresis-mass spectrometry (CE-MS) analysis of individual vitamin B or B-complex vitamins. Microchip capillary electrophoresis (ME) offers less consumption of background electrolyte and reagents than CE, and fast separation as having several channels for high-throughput. ME based on ZipChip integrates sample injection, electrophoretic separation, and ESI functions into one platform, herein, for the first time, in this paper, the ME-MS based on ZipChip platform was investigated and demonstrated preliminarily a significant improvement over existing techniques. Because: the ME-MS method has a linear response with excellent precision for replicate injections and LODs lower than 4 ppb; The method is simple and fast (<3 min per sample), using a small amount of sample (∼5 nL) with low reagent consumption, making it suitable for high-throughput applications; The inter/intraday reproducibility (RSD %) is less than 3 %, which is important for clinic application.

High-throughput relative quantification of fatty acids by 12-plex isobaric labeling and microchip capillary electrophoresis - Mass spectrometry

BACKGROUND

Fatty acids (FAs) are essential cellular components and play important roles in various biological processes. Importantly, FAs produced by microorganisms from renewable sugars are considered sustainable substrates for biodiesels and oleochemicals. Their complex structures and diverse functional roles in biochemical processes necessitate the development of efficient and accurate methods for their quantitative analysis.

RESULTS

Here, we developed a novel method for relative quantification of FAs by combining 12-plex isobaric N,N-dimethyl leucine-derivatized ethylenediamine (DiLeuEN) labeling and microchip capillary electrophoresis-mass spectrometry (CE-MS). This method enables simultaneous quantification of 12 samples in a single MS analysis. DiLeuEN labeling introduced tertiary amine center structure into FAs, which makes them compatible with the positive mode separation of commercial microchip CE systems and further improves the sensitivity. The CE separation parameters were optimized, and the quantification accuracy was assessed using FA standards. Microchip CE-MS detection exhibited high sensitivity with a femtomole level detection limit and a total analysis time within 8 min. Finally, the applicability of our method to complex biological samples was demonstrated by analyzing FAs produced by four industrially relevant yeast strains (Saccharomyces cerevisiae, Yarrowia lipolytica YB-432, Yarrowia lipolytica Po1f and Rhodotorula glutinis). The analysis time for each sample is less than 1 min.

SIGNIFICANCE

This work addresses the current challenges in the field by introducing a method that combines microchip-based capillary electrophoresis separation with multiplex isobaric labeling. Our method not only offers remarkable sensitivity and rapid analysis speed but also the capability to quantify fatty acids across multiple samples simultaneously, which holds significant potential for extensive application in FA quantitative studies in diverse research areas, promising an enhanced understanding of FA functions and mechanisms.

Investigating the Merits of Microfluidic Capillary Zone Electrophoresis-Mass Spectrometry (CZE-MS) in the Bottom-Up Characterization of Larger RNAs

Established bottom-up approaches for the characterization of nucleic acids (NAs) rely on the strand-cleavage activity of nucleotide-specific endonucleases to generate smaller oligonucleotides amenable to gas-phase sequencing. The complexity of these hydrolytic mixtures calls for the utilization of a front-end separation to facilitate full mass spectrometric (MS) characterization. This report explored the merits of microfluidic capillary zone electrophoresis (CZE) as a possible alternative to common liquid chromatography techniques. An oligonucleotide ladder was initially employed to investigate the roles of fundamental analyte features and experimental parameters in determining the outcome of CZE-MS analyses. The results demonstrated the ability to fully resolve the various rungs into discrete electrophoretic peaks with full-width half-height (FWHH) resolution that was visibly affected by the overall amount of material injected into the system. Analogous results were obtained from a digestion mixture prepared by treating yeast tRNAPhe (75 nt) with RNase T1, which provided several well-resolved peaks in spite of the increasing sample heterogeneity. The regular shapes of such peaks, however, belied the fact that most of them contained sets of comigrating species, as shown by the corresponding MS spectra. Even though it was not possible to segregate each species into an individual electrophoretic peak, the analysis still proved capable of unambiguously identifying a total of 29 hydrolytic products, which were sufficient to cover 96% of the tRNAPhe's sequence. Their masses accurately reflected the presence of modified nucleotides characteristic of this type of substrate. The analysis of a digestion mixture obtained from the 364 nt HIV-1 5'-UTR proved to be more challenging. The electropherogram displayed fewer well-resolved peaks and significantly greater incidence of product comigration. In this case, fractionating the highly heterogeneous mixture into discrete bands helped reduce signal suppression and detection bias. As a result, the corresponding MS data enabled the assignment of 248 products out of the possible 513 predicted from the 5'-UTR sequence, which afforded 100% sequence coverage. This figure represented a significant improvement over the 36 total products identified earlier under suboptimal conditions, which afforded only 57% coverage, or the 83 observed by direct infusion nanospray-MS (72%). These results provided a measure of the excellent potential of the technique to support the bottom-up characterization of progressively larger NA samples, such as putative NA therapeutics and mRNA vaccines.