A new strategy for the discovery of epimedium metabolites using high-performance liquid chromatography with high resolution mass spectrometry

In this paper, a new strategy of drug metabolite discovery and identification was established using high-performance liquid chromatography with high resolution mass spectrometry (HPLC–HRMS) and a mass spectral trees similarity filter (MTSF) technique. The MTSF technique was developed as a means to rapidly discover comprehensive metabolites from multiple active components in a complicated biological matrix. Using full-scan mass spectra as the stem and data-dependent subsequent stage mass spectra to form branches, the HRMS and multiple-stage mass spectrometric data from detected compounds were converted to mass spectral trees data. Potential metabolites were discovered based on the similarity between their mass spectral trees and that known compounds or metabolites in a mass spectra trees library. The threshold value for match similarity scores was set at above 200, allowing approximately 80% of interference to be filtered out. A total of 115 metabolites of five flavonoid monomers (epimedin A, epimedin B, epimedin C, icariin, and baohuoside I) and herbal extract of epimedium were discovered and identified in rats via this new strategy. As a result, a metabolic profile for epimedium was obtained and a metabolic pathway was proposed. In addition, comparing to the widely used neutral loss filter (NLF), product ion filter (PIF), and mass defect filter (MDF) techniques, the MTSF technique was shown superior efficiency and selectivity for discovering and identifying metabolites in traditional Chinese medicine (TCM).     

Rapid characterization of chlorogenic acids in Duhaldea nervosa based on ultra‐high‐performance liquid chromatography–linear trap quadropole‐Orbitrap‐mass spectrometry and mass spectral trees similarity filter technique

Duhaldea nervosa (Wallich ex Candolle) A. Anderberg has been traditionally used as a food spice and also in folk medicine for treating traumatic injury and relieving rheumatism, especially accelerating the healing of a fracture. However, so far as we are aware, the chemical constituents have not been fully investigated. In this study, a practical method of mass spectral trees similarity filter, a data‐mining technique, was developed and evaluated for the rapid detection and identification complicated constituents based on ultra‐high‐performance liquid chromatography–linear trap quadropole‐Orbitrap‐mass spectrometry. Finally, a total of 47 chlorogenic acids, including 19 monoacyl‐quinic acids, 22 diacyl‐quinic acids, and six triacyl‐quinic acids, were unambiguously or tentatively identified based on their accurate mass measurement, chromatographic retention, MSⁿ spectra, and bibliography data. To our best knowledge, it is the first time to report the chlorogenic acids of D. nervosa, which would be beneficial for the further material basis and quality research. Meanwhile, this mass spectral trees similarity filter method could be envisioned to exhibit a wide application for the identification of complicated components from botanical extracts.     

Identification of substances migrating from plastic baby bottles using a combination of low‐resolution and high‐resolution mass spectrometric analysers coupled to gas and liquid chromatography

This work presents a strategy for elucidation of unknown migrants from plastic food contact materials (baby bottles) using a combination of analytical techniques in an untargeted approach. First, gas chromatography (GC) coupled to mass spectrometry (MS) in electron ionisation mode was used to identify migrants through spectral library matching. When no acceptable match was obtained, a second analysis by GC‐(electron ionisation) high resolution mass spectrometry time of flight (TOF) was applied to obtain accurate mass fragmentation spectra and isotopic patterns. Databases were then searched to find a possible elemental composition for the unknown compounds. Finally, a GC hybrid quadrupole‐TOF‐MS with an atmospheric pressure chemical ionisation source was used to obtain the molecular ion or the protonated molecule. Accurate mass data also provided additional information on the fragmentation behaviour as two acquisition functions with different collision energies were available (MS^E approach). In the low‐energy function, limited fragmentation took place, whereas for the high‐energy function, fragmentation was enhanced. For less volatile unknowns, ultra‐high pressure liquid chromatography‐quadrupole‐TOF‐MS was additionally applied. Using a home‐made database containing common migrating compounds and plastic additives, tentative identification was made for several positive findings based on accurate mass of the (de)protonated molecule, product ion fragments and characteristic isotopic ions. Six illustrative examples are shown to demonstrate the modus operandi and the difficulties encountered during identification. The combination of these techniques was proven to be a powerful tool for the elucidation of unknown migrating compounds from plastic baby bottles. Copyright © 2015 John Wiley & Sons, Ltd.     

Analysis of nitrogenous organic compounds from mainstream cigarette smoke using low‐temperature solvent extraction followed by comprehensive two‐dimensional gas chromatography with high‐resolution time‐of‐flight mass spectrometry

A method involving comprehensive two‐dimensional gas chromatography coupled to high‐resolution time‐of‐flight mass spectrometry was developed and applied to the analysis of nitrogenous organic compounds present in mainstream cigarette smoke trapped on self‐designed equipment. The samples were prepared using low‐temperature solvent extraction under liquid nitrogen and analyzed by comprehensive two‐dimensional gas chromatography with high‐resolution time‐of‐flight mass spectrometry. Important experimental parameters, such as the type and volume of the extraction solvent and flow rate of smoking, were optimized to improve the analysis parameter. The results indicated that 180 mL of diethyl ether in the low‐temperature solvent extraction apparatus system with a 4 mL/min smoke flow rate were the optimal conditions. Then, 85 nitrogenous organic compounds were identified and quantified using a mass spectral library search, accurate mass ion and N‐rules of a molecular formula for nitrogen compounds. Finally, a comparison of the low temperature solvent extraction method and Cambridge filter pad method indicated that more peaks, a higher peak volume and better repeatability were obtained using the low‐temperature solvent extraction method.     

Recent applications of gas chromatography with high‐resolution mass spectrometry

Gas chromatography coupled to high‐resolution mass spectrometry is a powerful analytical method that combines excellent separation power of gas chromatography with improved identification based on an accurate mass measurement. These features designate gas chromatography with high‐resolution mass spectrometry as the first choice for identification and structure elucidation of unknown volatile and semi‐volatile organic compounds. Gas chromatography with high‐resolution mass spectrometry quantitative analyses was previously focused on the determination of dioxins and related compounds using magnetic sector type analyzers, a standing requirement of many international standards. The introduction of a quadrupole high‐resolution time‐of‐flight mass analyzer broadened interest in this method and novel applications were developed, especially for multi‐target screening purposes. This review is focused on the development and the most interesting applications of gas chromatography coupled to high‐resolution mass spectrometry towards analysis of environmental matrices, biological fluids, and food safety since 2010. The main attention is paid to various approaches and applications of gas chromatography coupled to high‐resolution mass spectrometry for non‐target screening to identify contaminants and to characterize the chemical composition of environmental, food, and biological samples. The most interesting quantitative applications, where a significant contribution of gas chromatography with high‐resolution mass spectrometry over the currently used methods is expected, will be discussed as well.     

Accurate identification of dimers from α‐pinene oxidation using high‐resolution collision‐induced dissociation mass spectrometry

Interest in mass spectrometry of highly oxidized dimers from α‐pinene oxidation has increased in the atmospheric chemistry field. Here, we apply high‐resolution collision‐induced dissociation mass spectrometry (HR‐CID‐MS) with an atmospheric pressure ionization source to investigate in detail how α‐pinene‐derived dimers are detected and identified by MS. The resulting HR‐CID spectra and specific fragmentation patterns suggest that a large fraction of dimer ions detected in full‐scan mass spectra can be hydrogen‐bonded artifact clusters and the residual small fraction includes covalently bonded actual dimers. We also show how individual fractions of the artifact clusters and actual dimers are calculated using the HR‐CID spectra.     

Development of variance‐filtered instrumental transfer methods for high‐resolution NMR spectroscopy

The introduction of a variance‐filter to both direct standardization (DS) and piece‐wise direct standardization (PDS) instrumental transfer methods for the analysis of NMR spectral data is described. The variance‐filter modification allows for the identification of regions in the NMR spectra that are not adequately represented by the limited number of transfer calibration samples used during the calculation of the instrument‐to‐instrument transfer matrix. For these spectral frequencies, the corresponding portion of the transfer matrix is replaced by identity (or scaled identity) prior to the secondary instrumental data sets being transferred to the target instrument response. The spectral matching performance of the variance‐filtered instrumental transfer method as applied to high‐resolution ¹H NMR spectra is presented along with possible uses and limitations. Copyright © 2010 John Wiley & Sons, Ltd.     

Non‐target environmental analysis by liquid chromatography/high‐resolution mass spectrometry with a product ion and neutral loss database

Despite the increasing detection of emerging substances in the environment, the identity of most are left unknown due to the lack of efficient identification methods. We developed a non‐target analysis method for identifying unknown substances in the environment by liquid chromatography/high‐resolution mass spectrometry (LC/HRMS) with a product ion and neutral loss database (PNDB). The present analysis describes an elucidation method with elemental compositions of the molecules, product ions, and corresponding neutral losses of the unknown substance: (1) with the molecular formula, possible molecular structures are retrieved from two chemical structure databases (PubChem and ChemSpider); then (2) with the elemental compositions of product ions and neutral losses, possible partial structures are retrieved from the PNDB; and finally, (3) molecular structures that match the possible partial structures are listed in order of number of hits. A molecular structure with a higher number of hits is more similar to the structure of the analyzed substance. The performance of the non‐target method was evaluated by simulated analysis of 150 LC/HRMS spectra registered in MassBank. First, all substances of the same mass data (41/41) and 68% (39/57) of the mass data of the same substances not registered in the PNDB were elucidated. It was demonstrated that 14% (7/52) and 31% (16/52) of the substances with no mass spectral data registered in the PNDB were obtained at the first and within the fifth place, respectively. Owing to the fact that 10 of the total hits occurred in product ions and neutral losses, almost 50% of the substances evaluated with this method were placed at the top 4 positions in the similarity ranking. Importantly, the proposed method is effective for analyzing mass spectral data that has not been registered in the PNDB and thus is expected to be used for a variety of non‐target analyses.     

Differentiating Westlake Longjing tea from the first‐ and second‐grade producing regions using ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry‐based untargeted metabolomics in combination with chemometrics

There are numerous articles published for geographical discrimination of tea. However, few research works focused on the authentication and traceability of Westlake Longjing green tea from the first‐ and second‐grade producing regions because the tea trees are planted in a limited growing zone with identical cultivate condition. In this work, a comprehensive analytical strategy was proposed by ultrahigh performance liquid chromatography‐quadrupole time‐of‐flight mass spectrometry‐based untargeted metabolomics coupled with chemometrics. The automatic untargeted data analysis strategy was introduced to screen metabolites that expressed significantly among different regions. Chromatographic features of metabolites can be automatically and efficiently extracted and registered. Meanwhile, those that were valuable for geographical origin discrimination were screened based on statistical analysis and contents in samples. Metabolite identification was performed based on high‐resolution mass values and tandem mass spectra of screened peaks. Twenty metabolites were identified, based on which the two‐way encoding partial least squares discrimination analysis was built for geographical origin prediction. Monte Caro simulation results indicated that prediction accuracy was up to 99%. Our strategy can be applicable for practical applications in the quality control of Westlake Longjing green tea.     

Comprehensive identification and structural characterization of target components from Gelsemium elegans by high‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry based on accurate mass databases combined with MS/MS spectra

This study reports an applicable analytical strategy of comprehensive identification and structure characterization of target components from Gelsemium elegans by using high‐performance liquid chromatography quadrupole time‐of‐flight mass spectrometry (LC‐QqTOF MS) based on the use of accurate mass databases combined with MS/MS spectra. The databases created included accurate masses and elemental compositions of 204 components from Gelsemium and their structural data. The accurate MS and MS/MS spectra were acquired through data‐dependent auto MS/MS mode followed by an extraction of the potential compounds from the LC‐QqTOF MS raw data of the sample. The same was matched using the databases to search for targeted components in the sample. The structures for detected components were tentatively characterized by manually interpreting the accurate MS/MS spectra for the first time. A total of 57 components have been successfully detected and structurally characterized from the crude extracts of G. elegans , but has failed to differentiate some isomers. This analytical strategy is generic and efficient, avoids isolation and purification procedures, enables a comprehensive structure characterization of target components of Gelsemium and would be widely applicable for complicated mixtures that are derived from Gelsemium preparations. Copyright © 2017 John Wiley & Sons, Ltd.     

Neuropeptidomics: Comparison of parallel reaction monitoring and data‐independent acquisition for the analysis of neuropeptides using high‐resolution mass spectrometry

Targeted peptide quantitation by mass spectrometry is a rapidly emerging field. Traditionally it relied on the development and validation of multiple reaction monitoring assays that could comply with a high level of sensitivity, specificity, accuracy and reproducibility in complex biological samples. However, with the introduction of high‐resolution mass spectrometers, other acquisition modes could provide more comprehensive datasets for identification and quantification but also for in‐depth data mining. The objective of this study was to evaluate two analytical approaches, parallel‐reaction monitoring (PRM) and data‐independent analysis (DIA) using a hybrid Quadrupole–Orbitrap mass spectrometer for the quantification of neuropeptides in animal spinal cord tissues. Mouse spinal cord tissues were harvested, homogenized and neuropeptides extracted using a C₁₈ solid‐phase extraction protocol. Chromatography was achieved using a Thermo Biobasic C₈ 100 × 1 mm (5 μm) column. The initial mobile phase conditions consisted of acetonitrile and water (both containing 0.1% of formic acid) at a ratio of 5:95. An 11 min linear gradient was applied up to a ratio of 50:50 and maintained for 3 min. The flow rate was fixed at 75 μL/min and 2 μL of sample was injected. Mass spectrometry analyses were performed using a Thermo Q Exactive Plus MS using PRM and DIA approaches. Quantitative data using an isotopic dilution and a label‐free strategy were obtained for both methods and statistically compared. Using both approaches, we were able to clearly detect endogenous neuropeptides. However, with DIA, mass spectra alone could not distinguish Leu‐Enk and Met‐Enk. We used a Bland–Altman plot (Difference plot) to analyze the agreement between both approaches and no systematic bias was observed. Further statistical analyses, including variance analysis, showed more variability in DIA compared with PRM mode. Further analyses were performed using a label‐free approach and confirmed an increase of the variance using a DIA approach.     

Comprehensive plasma‐screening for known and unknown substances in doping controls

Occasionally, doping analysis has been recognized as a competitive challenge between cheating sportsmen and the analytical capabilities of testing laboratories. Both have made immense progress during the last decades, but obviously the athletes have the questionable benefit of frequently being able to switch to new, unknown and untested compounds to enhance their performance. Thus, as analytical counteraction and for effective drug testing, a complementary approach to classical targeted methods is required in order to implement a comprehensive screening procedure for known and unknown xenobiotics. The present study provides a new analytical strategy to circumvent the targeted character of classical doping controls without losing the required sensitivity and specificity. Using 50 µL of plasma only, the method potentially identifies illicit drugs in low ng/mL concentrations. Plasma provides the biological fluid with the circulating, unmodified xenobiotics; thus the identification of unknown compounds is facilitated. After a simple protein precipitation, liquid chromatographic separation and subsequent detection by means of high resolution/high accuracy orbitrap mass spectrometry, the procedure enables the determination of numerous compounds from different classes prohibited by the World Anti‐Doping Agency (WADA). A new hyphenated mass spectrometry technology was employed without precursor ion selection for higher collision energy dissociation (HCD) fragmentation experiments. Thus the mass spectra contained all the desired information to identify unknown substances retrospectively. The method was validated for 32 selected model compounds for qualitative purposes considering the parameters specificity, selectivity, limit of detection (<0.1–10 ng/mL), precision (9–28%), robustness, linearity, ion suppression and recovery (80–112%). In addition to the identification of unknown compounds, the plasma samples were simultaneously screened for known prohibited targets. Copyright © 2010 John Wiley & Sons, Ltd.     

Metabolite identification of the antimalarial piperaquine in vivo using liquid chromatography–high‐resolution mass spectrometry in combination with multiple data‐mining tools in tandem

Artemisinin‐based combination therapy is widely used for the treatment of uncomplicated Plasmodium falciparum malaria, and piperaquine (PQ) is one of important partner drugs. The pharmacokinetics of PQ is characterized by a low clearance and a large volume of distribution; however, metabolism of PQ has not been thoroughly investigated. In this work, the metabolite profiling of PQ in human and rat was studied using liquid chromatography tandem high‐resolution LTQ‐Orbitrap mass spectrometry (HRMS). The biological samples were pretreated by solid‐phase extraction. Data processes were carried out using multiple data‐mining techniques in tandem, i.e., isotope pattern filter followed by mass defect filter. A total of six metabolites (M1–M6) were identified for PQ in human (plasma and urine) and rat (plasma, urine and bile). Three reported metabolites were also found in this study, which included N‐oxidation (M1, M2) and carboxylic products (M3). The subsequent N‐oxidation of M3 resulted in a new metabolite M4 detected in urine and bile samples. A new metabolic pathway N‐dealkylation was found for PQ in human and rat, leading to two new metabolites (M5 and M6). This study demonstrated that LC‐HRMSⁿ in combination with multiple data‐mining techniques in tandem can be a valuable analytical strategy for rapid metabolite profiling of drugs. Copyright © 2016 John Wiley & Sons, Ltd.     

Detection and characterization of ticlopidine conjugates in rat bile using high‐resolution mass spectrometry: applications of various data acquisition and processing tools

Ticlopidine, an antiplatelet drug, undergoes extensive oxidative metabolism to form S‐oxide, N‐oxide, hydroxylated and dealkylated metabolites. However, metabolism of ticlopidine via conjugation has not been thoroughly investigated. In this study, multiple data acquisition and processing tools were applied to the detection and characterization of ticlopidine conjugates in rat bile. Accurate full‐scan mass spectrometry (MS) and collision‐induced dissociation (CID) MS/MS data sets were recorded using isotope pattern‐dependent acquisition on an LTQ/Orbitrap system. In addition, mass spectral data from online H/D exchanging and high collision energy dissociation (HCD) were recorded. Data processes were carried out using extracted ion chromatography (EIC), mass defect filter (MDF) and isotope pattern filter (IPF). The total ion chromatogram displayed a few major conjugated metabolites and many endogenous components. Profiles from EIC and IPF processes exhibited multiple conjugates with no or minimal false positives. However, ticlopidine conjugates that were not predictable or lost a chorine atom were not found by EIC or IPF, respectively. MDF was able to detect almost all of ticlopidine conjugates although it led to a few more false positives. In addition to CID spectra, data from HCD, H/D exchanging experiments and isotope pattern simulation facilitated structural characterization of unknown conjugates. Consequently, 20 significant ticlopidine conjugates, including glucuronide, glutathione, cysteinylglycine, cysteine and N‐acetylcysteine conjugates, were identified in rat bile, a majority of which are associated with bioactivation and not previously reported. This study demonstrates the utility and limitation of various high‐resolution MS‐based data acquisition and processing techniques in detection and characterization of conjugated metabolites. Copyright © 2013 John Wiley & Sons, Ltd.     

Characterization of the potential new phthalides in Ligusticum chuanxiong Hort. using ultra‐performance liquid chromatography coupled with quadrupole time of flight tandem mass spectrometry

The characterization of unknown compounds is still a great challenge currently. A strategy for deduction of potential new phthalides through the characterization of isomers based on ultra‐performance liquid chromatography coupled with quadrupole time of flight tandem mass spectrometry was proposed here to characterize the unknown compounds of Ligusticum chuanxiong Hort. (Chuanxiong). This proposed strategy consisted of four steps: (1) the high resolution MS data was collected, and the peaks were screened preliminarily by UNIFI^TM platform based on the in‐house database; (2) the fragmentation patterns and the characteristic fragments were summarized based on the representative standards; (3) the target compounds were identified based on the fragmentation rules, standards comparison and false positive exclusion; (4) the unknown components were structurally characterized according to the accurate mass and fragmentation patterns analysis. This strategy was successfully applied to the identification and deduction of phthalides in Chuanxiong. A total of 81 phthalides were detected. Fifty‐five known phthalides were identified, and 26 potential new phthalides were characterized. This research enriched the material basis of Chuanxiong, and provided a liquid chromatography tandem mass spectrometry‐oriented method for the discovery of the potential new compounds.     

Simultaneous screening and determination of 18 illegal adulterants in herbal medicines and health foods for male sexual potency by ultra‐fast liquid chromatography‐electrospray ionization tandem mass spectrometry

An ultra‐fast liquid chromatography‐electrospray ionization tandem mass spectrometry method was developed and validated to simultaneously screen, confirm, and determine 18 illegal adulterants in herbal medicines and health foods for male sexual potency. The separation was achieved on a Shim‐Pack XR‐ODS II column (2.0 × 100 mm, 2.2 μm) with acetonitrile and aqueous solution (12 mmol/L ammonium formate, 0.01% acetic acid) as mobile phase at a flow rate of 0.4 mL/min with a gradient elution. The column temperature was maintained at 40°C and the run time was within 18 min. The 18 illegal adulterants were detected in electrospray ionization positive mode by multiple‐reaction monitoring. All the calibration curves showed good linearity with correlation coefficient (r) higher than 0.996 within the tested concentration ranges. The extraction recoveries and relative recoveries were in the range of 79.5–114% and 82.0–120%, respectively. The RSD of repeatability and intermediate precision was all less than 18% and the accuracy was in the range of 81.7–118%. The intra‐day and inter‐day stability was in the range of 86.8–110%. The validated method was successfully applied to screen, confirm, and determine 16 samples. Nine products were confirmed to contain illegal adulterants and the contents of adulterants were related to the therapeutic dosages.     

Qualitative and quantitative determination of YiXinShu Tablet using ultra high performance liquid chromatography with Q Exactive hybrid quadrupole orbitrap high‐resolution accurate mass spectrometry

To clarify and quantify the chemical profile of YiXinShu Tablet rapidly, a feasible and accurate strategy was developed by applying ultra high performance liquid chromatography with Q Exactive hybrid quadrupole orbitrap high‐resolution accurate mass spectrometry. A total of 105 components were identified, including 25 phenanthraquinones, 11 lactones, 19 lignans, 24 acids, and 26 other compounds. Among them, 26 major compounds were unambiguously detected by comparing with reference standards. And 19 of these compounds in three batches of YiXinShu Tablet were selected for quantitative determination. (Z )‐Ligustilide, salvianic acid A, salvianolic acid A, salvianolic acid B, and rosmarinic acid were abundant in these three batches with contents over 1 mg/g. The established analysis methods were examined to be accurate and feasible. The results show that the ultra high performance liquid chromatography with Q Exactive hybrid quadrupole orbitrap high‐resolution accurate mass spectrometry method has a powerful qualitative ability and promising quantitative application.     

Travelling‐wave ion mobility and negative ion fragmentation of high‐mannose N‐glycans

The isomeric structure of high‐mannose N‐glycans can significantly impact biological recognition events. Here, the utility of travelling‐wave ion mobility mass spectrometry for isomer separation of high‐mannose N‐glycans is investigated. Negative ion fragmentation using collision‐induced dissociation gave more informative spectra than positive ion spectra with mass‐different fragment ions characterizing many of the isomers. Isomer separation by ion mobility in both ionization modes was generally limited, with the arrival time distributions (ATD) often showing little sign of isomers. However, isomers could be partially resolved by plotting extracted fragment ATDs of the diagnostic fragment ions from the negative ion spectra, and the fragmentation spectra of the isomers could be extracted by using ions from limited areas of the ATD peak. In some cases, asymmetric ATDs were observed, but no isomers could be detected by fragmentation. In these cases, it was assumed that conformers or anomers were being separated. Collision cross sections of the isomers in positive and negative fragmentation mode were estimated from travelling‐wave ion mobility mass spectrometry data using dextran glycans as calibrant. More complete collision cross section data were achieved in negative ion mode by utilizing the diagnostic fragment ions. Examples of isomer separations are shown for N‐glycans released from the well‐characterized glycoproteins chicken ovalbumin, porcine thyroglobulin and gp120 from the human immunodeficiency virus. In addition to the cross‐sectional data, details of the negative ion collision‐induced dissociation spectra of all resolved isomers are discussed. Copyright © 2016 John Wiley & Sons, Ltd.     

A hierarchical screening method for detection of illegal adulterants in Fur seal ginseng pills by profiling analysis of HPLC multi‐dimensional fingerprints

A novel method for hierarchical screening of illegal adulterants in Fur seal ginseng pills products was developed by multi‐dimensional fingerprint profiling analysis. Fingerprint feature of the samples was acquired by high‐performance liquid chromatography analysis of 11 batches of samples with diode array detector and fluorescence detector, and then potential illegal adulterants including phosphodiesterase type‐5 inhibitors, androgens, α receptor antagonists and yohimbine, were further separated at multiple wavelengths to reduce or remove interferences from sample matrix for highlight their chromatographic characteristics. Accordingly, a hierarchical screening strategy was designed by first‐order and second‐order fingerprints combined with spectral examination to achieve high accuracy and reliability. The method was successfully applied to screening of illegal adulterants in real samples, and it also exhibited good quantification performance through validation tests. From 16 batches of samples, three suspected samples were confirmed to be positive, containing 9.37μg/g of testosterone, 18.8 μg/g of tadalafil, and 48.5 μg/g of sildenafil, respectively. The recoveries and relative standard deviations were in the range of 83.6–103.1% and 4.2–6.8%, respectively. The proposed method provided a simple, efficient and promising alternative to monitoring functional foods.     

Qualitative screening of absorbed indoloquinazoline alkaloids and their metabolites in rat plasma after the oral administration of Wu‐Zhu‐Yu decoction by high‐resolution mass spectrometry with multiple data mining algorithms

A rapid and sensitive liquid chromatography with high‐resolution mass spectrometry method with multiple data processing algorithms was developed and applied for the metabolite profiling of evodiamine and its analogous alkaloids in rat plasma after the administration of Wu‐Zhu‐Yu decoction. All samples were purified using hydrophilic‐lipophilic balanced solid‐phase extraction cartridges and analyzed by a Sciex TripleTOF 5600⁺ mass spectrometer with a 35 min liquid chromatography gradient elution. High‐resolution full‐scan mass spectrometry and information‐dependent acquisition tandem mass spectrometry data were analyzed using multiple data processing approaches. The results indicated that the detected eight prototype alkaloids could be metabolized to 58 metabolites through both phase I and phase II reactions. Oxidation was demonstrated to be the principle metabolic pathway of the parent compounds. The study contributes to the understanding of the absorption and metabolism of the alkaloids in Wu‐Zhu‐Yu decoction and provides a detailed analysis of scientific data.