Deciphering the chemical composition of Ganoderma lucidum from different geographical origins by mass spectrometry molecular networking coupled with multivariate analysis

Ganoderma lucidum is a medicinal fungus that has been widely used in China and many Asian countries for thousands of years. This once rare macrofungus has now been artificially cultivated in a number of regions in China. However, detailed knowledge of its composition across different geographical origins is still lacking, as are analytical methods for comprehensive profiling of the diverse phytochemicals contained in G. lucidum. In this work, an on-demand strategy based on high-resolution MS and molecular networking is applied for natural product characterization, which led to the identification of 84 constituents in G. lucidum. Moreover, multivariate analysis, including hierarchical cluster analysis and orthogonal partial least squares-discriminant analysis, was used to analyze the (dis)similarity of the G. lucidum samples collected from the three main production areas (i.e., Jilin, Henan and Shandong Province). The results revealed a significant variation in the chemical composition of samples from different provinces. Marker constituents corresponding to the differentiation were then screened in terms of the variable importance in projection value, P-value and fold change. A total of 24 constituents were identified as geoherbalism markers, such as ganoderenic acid A for Henan, ganolucidic acid B for Jilin and ganodernoid D for Shandong. This proof-of-concept application demonstrates that combining MS molecular networking with meticulous multivariate analysis can provide a sensitive and comprehensive analytical approach for the quality assessment of traditional Chinese medicine ingredients. This study also suggests that the bioactivity and efficacy from different origins should be further evaluated considering the large difference in chemical compositions.     

From molecules to visuals: Empowering drug discovery and development with mass spectrometry imaging

Over the past three decades, mass spectrometry imaging (MSI) has emerged as a valuable tool for the spatial localization of drugs and metabolites directly from tissue surfaces without the need for labels. MSI offers molecular specificity, making it increasingly popular in the pharmaceutical industry compared to conventional imaging techniques like quantitative whole-body autoradiography (QWBA) and immunohistochemistry, which are unable to distinguish parent drugs from metabolites. Across the industry, there has been a consistent uptake in the utilization of MSI to investigate drug and metabolite distribution patterns, and the integration of MSI with omics technologies in preclinical investigations. To continue the further adoption of MSI in drug discovery and development, we believe there are two key areas that need to be addressed. First, there is a need for accurate quantification of analytes from MSI distribution studies. Second, there is a need for increased interactions with regulatory agencies for guidance on the utility and incorporation of MSI techniques in regulatory filings. Ongoing efforts are being made to address these areas, and it is hoped that MSI will gain broader utilization within the industry, thereby becoming a critical ingredient in driving drug discovery and development.     

Coupling of imaging NEXAFS with secondary ion mass spectrometry for the chemical and isotopic analysis of presolar cosmic grains

We present first results of the combination of imaging photoemission electron spectroscopy with imaging mass spectrometry. Imaging NEXAFS was combined with TOF-SIMS in order to perform a spatially resolved chemical and isotopic analysis of microscopic grain samples. Imaging NEXAFS was used for the nondestructive lateral characterization of mineral phases prior to isotopically resolved mass analysis by imaging TOF-SIMS. This novel approach was demonstrated by performing a chemical and isotopic analysis of the rare presolar grain fraction present in the Murchison meteorite.     

Surface-activated chemical ionization combined with electrospray ionization and mass spectrometry for the analysis of cannabinoids in biological samples. Part I: analysis of 11-nor-9-carboxytetrahydro-cannabinol

Recently, electrospray ionization mass spectroscopy (ESI-MS) has been widely used for the identification of drugs of abuse and their metabolites in biological samples. However, the sensitivity and selectivity of this technique are commonly inadequate for the analysis of tetrahydrocannabinol (THC) and its metabolites at very low levels, such as those sometimes required in forensic and clinical-legal applications. We coupled electrospray ionization and surface-activated chemical ionization (ESI-SACI) to various types of mass analyzers (ion trap, triple quadrupole and orbitrap) (ESI-SACI-MS) to improve the detection of 11-nor-9-carboxy-tetrahydrocannabinol (THC-COOH), the most common marker of THC abuse. The benefits of this approach in terms of sensitivity and selectivity compared with a common ESI-MS approach are clearly demonstrated.     

Application of positive ion chemical ionisation and tandem mass spectrometry combined with gas chromatography to the trace level analysis of ethyl carbamate in bread

A rapid, sensitive and selective method has been developed and validated for the analysis of the contaminant ethyl carbamate (EC) in bread products at the part-per-billion level. The new procedure uses positive ion chemical ionisation (PICI) and tandem mass spectrometry (MS/MS), combined with gas chromatography (GC), on a 'bench-top' triple-quadrupole mass spectrometer. Ammonia was the PICI reagent gas of choice because of its ability to produce abundant [M+H]+ and [M+NH4]+ ions from EC and deuterium-labelled EC (LEC) used as an internal standard. For identification and quantification, selected reaction monitoring (SRM) was used to follow the precursor-to-product ion transitions of m/z 107 --> 90, m/z 107 --> 62 and m/z 90 --> 62 for EC, as well as m/z 112 --> 63 for the LEC internal standard. The limits of detection and quantification were 0.6 and 1.2 microg kg(-1), respectively, and the recovery of the method was 101 +/- 10% at 10 microg kg(-1) and 98 +/- 5% at 100 microg kg(-1). The precision of the method, established under conditions of intermediate reproducibility, did not exceed a relative standard deviation of 7%. The quantitative performance of the new GC/PICI-SRM procedure compared favourably with that of a reference method based on GC/MS and selected ion monitoring (correlation coefficient, r = 0.997). However, the new method had the advantages of reduced sample preparation time, improved sensitivity and unambiguous identification of EC at all concentrations. Application of the new method to the analysis of 50 UK breads showed that levels of EC ranged from 0.6 to 2.3 microg kg(-1) in retail products and from 3.1 to 12.2 microg kg(-1) for breads prepared using domestic breadmaking machines (dry weight basis). Toasting bread in a domestic toaster led to increases of between two- and three-fold in mean EC concentrations.     

Identification and quantitative analysis of the chemical constituents of Gandouling tablets using ultra-high-performance liquid chromatography with quadrupole time-of-flight mass spectrometry

Gandouling tablets are used in a clinical agent for the treatment of hepatocellular degeneration; however, their chemical constituents have not been elucidated. Here, we screened and identified the chemical constituents of Gandouling tablets using ultra-high-performance liquid chromatography (UHPLC)-quadrupole time of flight/mass spectrometry. A method for the quality evaluation of Gandouling tablets was developed by combining the UHPLC fingerprints and the simultaneous quantitative analysis of multiple active ingredients. For fingerprint analysis, 20 shared peaks were identified to assess the similarities among the 10 batches of Gandouling tablets and the similarity was >0.9. The levels of nine representative active ingredients were simultaneously determined to ensure consistency in quality. A total of 99 chemical components were identified, including 18 alkaloids, 20 anthraquinones, 13 flavonoids, 11 phenolic acids, 9 polyphenols, 7 phenanthrenes, 5 sesquiterpenes, 3 curcuminoids, 2 lignans, 2 isoflavones, 2 dianthranones, and 7 other components. The retention times, molecular formulae, and secondary fragmentation information of these compounds were analyzed, and the cleavage pathways and characteristic fragments of some of the representative compounds were elucidated. This systematic analysis used to identify the chemical components of Gandouling tablets lays the foundation for its further quality control and research on their pharmacodynamic substances.     

Ultra high performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry and liquid chromatography with tandem mass spectrometry combined with chemometric analysis as an approach for the quality evaluation of Mume Fructus

Mume Fructus is an important traditional Chinese medicine that has been widely used in the treatment of intestinal diseases and asthma for thousands of years. In order to evaluate the quality of Mume Fructus in different processing methods, the main chemical components in Mume Fructus were investigated and a method was established for simultaneous quantification of organic acids of Mume Fructus. First, an optimized ultra-performance liquid chromatography-quadrupole-time of flight tandem-mass spectrometry method was used to identify the structures of main components in Mume Fructus. A total of 41 chemical compounds were identified, including 11 organic acids, 13 flavonoids, and three fatty acids. The contents of 11 organic acids in 18 batches of Mume Fructus from different processing methods were simultaneously determined by a liquid chromatography with tandem mass spectrometry method. The results of quantitative and hierarchical cluster analysis indicated that Mume Fructus under different processing methods were rich in the above 11 organic acids and the contents were obviously different. Taken together, the proposed quality evaluation method was fast and comprehensively reflects the content of the main chemical components in Mume Fructus under different processing methods, and provides a useful reference for the quality control and evaluation of Mume Fructus.     

Qualitative and quantitative analysis of the chemical constituents in Mahuang‐Fuzi‐Xixin decoction based on high performance liquid chromatography combined with time‐of‐flight mass spectrometry and triple quadrupole mass spectrometers

High‐performance liquid chromatography coupled with time‐of‐flight mass spectrometry (HPLC‐TOF/MS) and high‐performance liquid chromatography–triple quadrupole mass spectrometry (HPLC‐QQQ/MS/MS) were utilized to clarify the chemical constituents of Mahuang‐Fuzi‐Xixin Decoction. There are 52 compounds, including alkaloids, amino acids and organic acids were identified or tentatively characterized by their characteristic high resolution mass data by HPLC‐QQQ/MS/MS. In the subsequent quantitative analysis, 10 constituents, including methyl ephedrine, aconine, songrine, fuziline, neoline, talatisamine, chasmanine, benzoylmesaconine, benzoylaconine and benzoylhypaconine were simultaneously determined by HPLC‐QQQ/MS/MS with multiple reaction monitoring mode. Satisfactory linearity was achieved with wide linear range and fine determination coefficient (r > 0.9992). The relative standard deviations (RSD) of inter‐ and intra‐day precisions were <3%. This method was also validated by repeatability, stability and recovery with RSD <3% respectively. A highly sensitive and efficient method was established for chemical constituents studying, including identification and quantification of Mahuang‐Fuzi‐Xixin decoction.     

Classification of the medicinal plants of the genus Atractylodes using high‐performance liquid chromatography with diode array and tandem mass spectrometry detection combined with multivariate statistical analysis

Analytical methods using high‐performance liquid chromatography with diode array and tandem mass spectrometry detection were developed for the discrimination of the rhizomes of four Atractylodes medicinal plants: A. japonica, A. macrocephala, A. chinensis, and A. lancea. A quantitative study was performed, selecting five bioactive components, including atractylenolide I, II, III, eudesma‐4(14),7(11)‐dien‐8‐one and atractylodin, on twenty‐six Atractylodes samples of various origins. Sample extraction was optimized to sonication with 80% methanol for 40 min at room temperature. High‐performance liquid chromatography with diode array detection was established using a C₁₈ column with a water/acetonitrile gradient system at a flow rate of 1.0 mL/min, and the detection wavelength was set at 236 nm. Liquid chromatography with tandem mass spectrometry was applied to certify the reliability of the quantitative results. The developed methods were validated by ensuring specificity, linearity, limit of quantification, accuracy, precision, recovery, robustness, and stability. Results showed that cangzhu contained higher amounts of atractylenolide I and atractylodin than baizhu, and especially atractylodin contents showed the greatest variation between baizhu and cangzhu. Multivariate statistical analysis, such as principal component analysis and hierarchical cluster analysis, were also employed for further classification of the Atractylodes plants. The established method was suitable for quality control of the Atractylodes plants.     

Rapid Characterization of the major chemical constituents from Polygoni Multiflori Caulis by liquid chromatography tandem mass spectrometry and comparative analysis with Polygoni Multiflori Radix

Polygoni Multiflori Caulis is a traditional Chinese medicine that has been used for a long time to treat sleep disorders. However, the multiple chemical composition analysis has not been reported. In this study, a simple, rapid and effective ultra‐high performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry method was established to characterize the components of Polygoni Multiflori Caulis. In addition, a chemical comparative analysis was performed with Polygoni Multiflori Radix, another traditional Chinese medicine from the same plant, through multivariate statistical analysis and semi‐quantitative analysis to screen the difference in chemical ingredients between these two herbal medicines from same medicinal plant. A total of 33 peaks were detected within 25 min, and 28 of them were identified or tentatively characterized by comparing the retention time and mass spectrometry data. Based on the results, 12 characteristic components were screened out by multivariate statistical analysis, and their content change trends were compared by semi‐quantitative analysis.     

Optimization of quadrupole ion storage mass spectrometric conditions for the analysis of selected polybrominated diphenyl ethers. Comparative approach with negative chemical ionization and electron impact mass spectrometry

Gas chromatography coupled to quadrupole ion storage mass spectrometry (QISTMS) operating in the non-resonant mode is presented as an innovative approach for the analysis of selected polybrominated diphenyl ethers (PBDEs). Although reductions in complexity and time needed for optimization are achieved in comparison with the resonant option, precise adjustment of the mass spectrometric conditions is required. Differences in isolation and fragmentation patterns of target species with degree of bromination were observed. The reliability of the method was confirmed by using standard solutions through the evaluation of certain quality parameters such as accuracy (92-108%), injection repeatability and reproducibility (coefficient of variation below 10% and 15%, respectively). Detection limits ranged from 62 to 621 fg, providing sensitivity similar to that of negative chemical ionisation (NCIMS) and greater than that of electron ionization mass spectrometry. The applicability of QISTMS method to real samples and matrix effects were evaluated through the analysis of some PBDE congeners in a sewage sludge sample from a Spanish waste-water treatment plant. Comparable results were obtained using QISTMS and NCIMS. According to these observations, QISTMS performed in the non-resonant mode may constitute a low-cost, rapid and reliable alternative to high-resolution devices for the analysis of selected PBDEs in environmental samples.     

Surface-activated chemical ionization ion trap mass spectrometry in the analysis of drugs in dilute urine samples. Part II: analysis of morphine and other street drugs

The new ionization method, called surface-activated chemical ionization (SACI), was employed for the analysis of fives drugs (morphine, codeine, 6-monoacetylmorphine (6-MAM), benzoylecgonine and cocaine) by ion trap mass spectrometry. The results so obtained have been compared with those achieved by using atmospheric pressure chemical ionization (APCI), no-discharge-APCI and electrospray ionization (ESI) clearly showing that SACI is the most sensible one mainly due to the high ionization efficiency and the lower chemical noise. The performance of SACI in terms of sensitivity and linearity was compared with the sensitivity and linearity obtained using APCI, no-discharge-APCI and ESI, showing that the new SACI approach gives rise to the best results. Then, SACI was used to analyze morphine, codeine, 6-MAM, benzoylecgonine and cocaine in urine samples. After the optimization of the instrumental parameters for a mixture of the standard compounds, eight urine samples were analyzed. They were strongly diluted (1 : 20 and 1 : 100) in order to prevent the chromatographic column damage due to the matrix composition. Furthermore, the diluted urine samples were directly analyzed, without pretreatment, through LC-MS and LC-MS/MS, and the obtained results are reported.     

Ionization suppression effects with condensed phase membrane introduction mass spectrometry: methods to increase the linear dynamic range and sensitivity

Condensed phase membrane introduction mass spectrometry (CP‐MIMS) is an online analytical method that allows for the direct, trace level measurement of a wide range of analytes in complex samples. The technique employs a semi‐permeable membrane that transfers analytes from a sample into a flowing acceptor solvent, which is directly infused to an atmospheric pressure ionization source, such as electrospray or atmospheric pressure chemical ionization. While CP‐MIMS and variants of the technique have been in the literature for nearly a decade, much of the work has focused on instrument development. Few studies have thoroughly addressed quantitative methods related to detection limits, ionization suppression, or linear dynamic range. We examine ionization suppression in the direct rapid quantitation of analytes by CP‐MIMS and introduce several analytical strategies to mitigate these effects, including the novel implementation of a continuously infused internal standard in the acceptor phase solvent, and modulation of acceptor phase flow rate. Several representative analytes were used to evaluate this approach with spiked, complex sample matrices, including primary wastewater effluent and artificial urine. Also reported are improved measured detection limits in the low part‐per‐trillion range, using a ‘stopped‐flow’ acceptor mode. Copyright © 2015 John Wiley & Sons, Ltd.     

Imaging fibrinogen adsorbed on noble metal surfaces with scanning tunneling microscopy: correlation of images with electron spectroscopy for chemical analysis, secondary ion mass spectrometry, and radiolabeling studies

Fibrinogen adsorption on gold and platinum surfaces has been studied with electron spectroscopy for chemical analysis (ESCA), secondary ion mass spectrometry (SIMS), ¹²⁵I labeling, and scanning tunneling microscopy (STM). Stable images of single molecules have been obtained, but are rare. ESCA, SIMS, and labeling studies confirm that absorbed fibrinogen is present on samples at monolayer and submonolayer coverages even when STM images show only a bare substrate. Imaging is more reproducible at high coverages at which single molecules cannot be resolved. Possible explanations for the failure of STM to observe adsorbed fibrinogen molecules are discussed.     

Method for the elucidation of the elemental composition of low molecular mass chemicals using exact masses of product ions and neutral losses: application to environmental chemicals measured by liquid chromatography with hybrid quadrupole/time-of-flight mass spectrometry

A method for elucidating the elemental compositions of low molecular weight chemicals, based primarily on mass measurements made using liquid chromatography (LC) with time-of-flight mass spectrometry (TOFMS) and quadrupole/time-of-flight mass spectrometry (LC/QTOFMS), was developed and tested for 113 chemicals of environmental interest with molecular masses up to approximately 400 Da. As the algorithm incorporating the method is not affected by differences in the instrument used, or by the ionization method and other ionization conditions, the method is useful not only for LC/TOFMS, but also for all kinds of mass spectra measured with higher accuracy and precision (uncertainties of a few mDa) employing all ionization methods and on-line separation techniques. The method involves calculating candidate compositions for intact ionized molecules (ionized forms of the sample molecule that have lost or gained no more than a proton, i.e., [M+H](+) or [M-H](-)) as well as for fragment ions and corresponding neutral losses, and eliminating those atomic compositions for the molecules that are inconsistent with the corresponding candidate compositions of fragment ions and neutral losses. Candidate compositions were calculated for the measured masses of the intact ionized molecules and of the fragment ions and corresponding neutral losses, using mass uncertainties of 2 and 5 mDa, respectively. Compositions proposed for the ionized molecule that did not correspond to the sum of the compositions of a candidate fragment ion and its corresponding neutral loss were discarded. One, 2-5, 6-10, 11-20, and >20 candidate compositions were found for 65%, 39%, 1%, 1%, and 0%, respectively, for the 124 ionized molecules formed from the 113 chemicals tested (both positive and negative ions were obtained from 11 of the chemicals). However, no candidate composition was found for 2% of the test cases (i.e., 3 chemicals), for each of which the measured mass of one of the product ions was in error by 5-6.7 mDa.     

Identification and characterization of the chemical constituents of Simiao Wan by ultra high performance liquid chromatography with mass spectrometry coupled to an automated multiple data processing method

The chemical constituents of Simiao Wan (SW), a traditional Chinese medicine preparation, are difficult to determine and remain unclear. To more efficiently detect ions, a multiple data processing approach has been used in the characterization of the compounds. In this study, a rapid and sensitive method based on ultra high performance liquid chromatography with mass spectrometry and the multiple data processing approach was established to characterize the chemical constituents of SW. Ultra high performance liquid chromatography with mass spectrometry coupled with the multiple data processing approach could efficiently remove nonrelated ion signals from accurate mass data. We report the application of the multiple data processing approach for comprehensive detection and rapid identification of chemical constituents of SW. Of note, the total analysis time for separation was less than 20 min without losing any resolution. In the variable, importance in projection plot of orthogonal projection to latent structure‐discriminant analysis, a total of 72 ions of interest (37 ions in positive mode, 38 ions in negative mode and three ions in both mode) were extracted or tentatively characterized based on their retention times, exact mass measurement for each molecular ion and subsequent fragment ions. In summary, the methodology proposed in this study could be valuable for the structural characterization and identification of the multiple constituents in the traditional Chinese medicine formula SW.     

Development of an analytical strategy to identify and classify the global chemical constituents of Ziziphi Spinosae Semen by using UHPLC with quadrupole time‐of‐flight mass spectrometry combined with multiple data‐processing approaches

According to traditional Chinese medical theory, Ziziphi Spinosae Semen needs to be stir‐fried before clinical application for its sedative‐hypnotic effect enhancement. A rapid and comprehensive analysis strategy of ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry and multiple data analysis platforms was developed for the efficient and sensitive identification of components in crude and parched Ziziphi Spinosae Semen to explore the composition changes that happen during the stir‐frying process. Both positive and negative ion modes were applied for mass spectrometry detection, and 40 components were identified from crude and parched Ziziphi Spinosae Semen, respectively. Principal component analysis and t‐test were applied to find differences between crude and parched Ziziphi Spinosae Semen. As a result, Ziziphi Spinosae Semen samples could be clearly divided into two groups according to their processing methods, and 19 key markers that contributed to the classification significantly (P < 0.05) were found. This kind of change in contents of components might be responsible for the recommended clinical application of parched Ziziphi Spinosae Semen.