Mass Spectrometry For Rapid Analysis Research Articles

Surface-enhanced laser desorption/ionization mass spectrometry for rapid analysis of organic environmental pollutants by using polydopamine nanospheres as a substrate

Polydopamine nanospheres (PDA) were designed to serve as a new substrate for surface-enhanced desorption/ionization mass spectrometry (SELDI-MS). Compared with conventional organic matrices, the PDA substrate showed superior LDI performance for analyzing a wide variety of environmental pollutants, including polycyclic aromatic hydrocarbons, bisphenols, benzophenones, sulfonamides, perfluorinated compounds and estrogens. Benzoapyrene was used to evaluate the ability of quantitative analysis and its corresponding limit of detection (LOD) of as low as 0.1 ng was achieved. High sensitivity and good reproducibility of PDA-based SELDI-MS allowed us to determine ultratrace PAHs in airborne particulate matters (PM2.5), and the corresponding concentration of BaP in different PM2.5 were 5.32, 8.97 and 9.79 ng m-3. Significantly, PDA exhibits the characteristics of simple synthesis, low cost, non-toxicity and less matrix interference, which provides the possibility for the sensitive analysis of organic small molecule pollutants at low concentrations in complex environmental samples.

Direct analysis in real time coupled with quadrupole-Orbitrap high-resolution mass spectrometry for rapid analysis of pyrethroid preservatives in wooden food contact materials.

A methodology is presented for the determination of four pyrethroid (PYR) preservatives in wooden food contact materials (FCMs) using direct analysis in real time (DART) coupled with quadrupole-Orbitrap high-resolution mass spectrometry (Q-Orbitrap HRMS). The sampling mode and critical parameters of the DART-Q-Orbitrap HRMS protocol were systematically investigated. Good linearity was achieved for the four analytes with correlation coefficients all greater than 0.99. The limits of detection (LODs) and limits of quantitation (LOQs) of the method were in the range of 0.04-0.20 mg kg-1 and 0.10-0.50 mg kg-1, respectively. The mean recoveries ranged from 72.1% to 82.7% with relative standard deviations (RSDs) from 5.2% to 11.8% at three spiked levels. The developed method was proved to be suitable for rapid screening of PYRs in complex wooden FCM samples to ensure product safety and consumer health.

Off-Colony Screening of Biosynthetic Libraries by Rapid Laser-Enabled Mass Spectrometry.

By leveraging advances in DNA synthesis and molecular cloning techniques, synthetic biology increasingly makes use of large construct libraries to explore large design spaces. For biosynthetic pathway engineering, the ability to screen these libraries for a variety of metabolites of interest is essential. If the metabolite of interest or the metabolic phenotype is not easily measurable, screening soon becomes a major bottleneck involving time-consuming culturing, sample preparation, and extraction. To address this, we demonstrate the use of automated laser-assisted rapid evaporative ionization mass spectrometry (LA-REIMS)-a form of ambient laser desorption ionization mass spectrometry-to perform rapid mass spectrometry analysis direct from agar plate yeast colonies without sample preparation or extraction. We use LA-REIMS to assess production levels of violacein and betulinic acid directly from yeast colonies at a rate of 6 colonies per minute. We then demonstrate the throughput enabled by LA-REIMS by screening over 450 yeast colonies within <4 h, while simultaneously generating recoverable glycerol stocks of each colony in real time. This showcases LA-REIMS as a prescreening tool to complement downstream quantification methods such as liquid chromatography-mass spectroscopy (LCMS). By prescreening several hundred colonies with LA-REIMS, we successfully isolate and verify a strain with a 2.5-fold improvement in betulinic acid production. Finally, we show that LA-REIMS can detect 20 out of a panel of 27 diverse biological molecules, demonstrating the broad applicability of LA-REIMS to metabolite detection. The rapid and automated nature of LA-REIMS makes this a valuable new technology to complement existing screening technologies currently employed in academic and industrial workflows.

Molecularly imprinted polymer solid-phase microextraction coupled with ultra high performance liquid chromatography and tandem mass spectrometry for rapid analysis of pyrrolizidine alkaloids in herbal medicine.

Pyrrolizidine alkaloids are the most widely distributed natural toxins, and pyrrolizidine alkaloid-containing herbal medicines are probably the most common poisonous plants affecting humans. We reported pyrrolizidine alkaloid-molecularly imprinted polymer solid-phase microextraction for the selective adsorption of toxic pyrrolizidine alkaloids from herbal medicine. A sulfonic compound, sodium allylsulfonate, was chosen as the functional monomer to interact with pyrrolizidine alkaloids through strong ionic interaction. To avoid template leakage and for the aim of cost saving, a relatively cheap dummy template was used for the fabrication of molecularly imprinted polymer-solid-phase microextraction fibers. The obtained fibers showed selective adsorption ability for four pyrrolizidine alkaloids, including europine, echimidine, lasiocarpine, and heliotrine. The extraction parameters, such as extraction time, extraction temperature, shaking speed, elution solvent and elution time, were optimized. Then ultra high performance liquid chromatography with mass spectrometry coupled with molecularly imprinted polymer-solid-phase microextraction method was developed for the fast and efficient analysis of four pyrrolizidine alkaloids from the model herbal plant Farfarae Flos. The established method was validated and exhibited satisfactory accuracy and precision. The present method provides an innovative and fast analytical strategy for the determination of trace toxic pyrrolizidine alkaloids in complicated samples.

Online extraction and cleanup-quadrupole time-of-flight tandem mass spectrometry for rapid analysis of bioactive components in natural products.

The challenges in direct analysis of a complex system (e.g., natural product, food, biological samples) by mass spectrometry (MS) are the sophisticated sample preparation methods and ionization suppression by matrix interferences. Consequently, a novel online extraction and cleanup-quadrupole time-of-flight tandem mass spectrometry (OLEC-QTOF-MS/MS) system was developed for rapid, efficient, and sensitive analysis of flavonoids in Citri Reticulatae Pericarpium (CRP). For the OLEC strategy, a guard column packed with solid CRP (0.5mg) and C18 gel was positioned on a manual injection valve, in which interferences with large polarities were online removed by methanol-0.1% formic acid (25:75, v/v) for 3min, while target flavonoids were online extracted by methanol-0.1% formic acid (70:30, v/v) for 10min for the subsequent QTOF-MS/MS analysis. The method was validated using official marker, hesperidin, by external standard method. Excellent linear ranges from 0.02 to 52.0μgL-1 (R2, 0.9935) with a limit of detection (LOD) of 0.006μg were obtained. Acceptable reproducibility (RSD 8.1 and 9.6% for intra- and inter-day variations) and recoveries (from 99.5 to 112.0%) were also attained. In addition, 20 flavonoids in CRP were identified according to their exact mass and fragmentation ions in MS/MS spectra, and five of them were reported for the first time. Obviously, OLEC-QTOF-MS/MS presented several advantages, such as simple operation and high sensitivity, which provided new perspectives for rapid analysis of bioactive components in complex natural products. Graphical Abstract ᅟ.

Charged Bubble Extractive Ionization Mass Spectrometry for Protein Analysis

Abstract Rapid mass spectrometry analysis of protein in liquid sample was carried out by using a charged bubble extractive ionization device. In this work, experimental parameters including gases (N2 and CO2), bubble path length, voltage, and gas pressure on the charged bubble extractive ionization of lysozyme were investigated. Under the optimum experimental parameters including CO2 as extraction gas, bubble path length of 32 cm, solution voltage of 2 kV, and gas pressure of 0.05 MPa, lysozyme in liquid sample were successfully detected with the limits of detection of 1 × 10−8 M in aqueous solution and 1 × 10−7 M in diluted urine (200 times with ultrapure water), respectively. In addition, the limit of detection of 1 × 10−5 M was obtained for undiluted urine sample. By comparing the desalting effects of charged bubble extractive ionization mass spectrometry with ESI-MS, it was found that the charged bubble extractive ionization method could obtain a wider and lower charge state distribution of protein ions, and showed higher tolerance facing non-volatile inorganic salts. Off-line study of the collected catalase after charged bubble extractive ionization showed that 53.9% enzyme activity was remained, which indicated that the proposed method was a soft ionization method. The method had merits including no sample pretreatment, no chemical reagent contamination and high speed, showing potential application to mass spectrometry analysis of protein components in solution samples.

Multistep Flow Synthesis of Diazepam Guided by Droplet-Accelerated Reaction Screening with Mechanistic Insights from Rapid Mass Spectrometry Analysis

Electrospray and Leidenfrost droplet accelerated reactions were used as a predictive tool for estimating the outcome of microfluidic synthesis as demonstrated by Wleklinski et al. Rapid analysis by electrospray-mass spectrometry (ESI-MS) also provided immediate feedback on reaction outcomes in flow reactions. Significant reaction acceleration was observed in electrospray relative to the corresponding bulk reaction. This rapid reaction screening and analysis method has allowed for the detection of previously unreported outcomes in the reaction between 5-chloro-2-(methylamino)benzophenone and haloacetyl chloride (halo = Cl or Br) in the continuous synthesis of diazepam. In our current study, a more detailed extension of the previous work, we report acceleration factors that are solvent dependent; additional byproducts that were observed on the microfluidic scale that were absent in the droplet reactions. Gaining insight from this combined droplet and microfluidic screening/rapid ESI-MS analysis approach, we...

Swab touch spray mass spectrometry for rapid analysis of organic gunshot residue from human hand and various surfaces using commercial and fieldable mass spectrometry systems

Organic gunshot residues, specifically methyl centralite (1,3-dimethyl-1,3-diphenylurea) and ethyl centralite (1,3-diethyl-1,3-diphenylurea), are characteristic compounds for which forensic analysts test when determining if an individual has discharged a firearm. These distinctive compounds have long been analyzed by several instrumental techniques, many of which involve extensive sample preparation or have lengthy analysis times. Presented here is an ambient ionization method that requires no sample preparation, offers real-time analysis, and can be paired with a portable ion trap mass spectrometer for in-situ analysis. Swab touch spray ionization utilizes a rayon-tipped swab that has an aluminum wire handle which can simply be swabbed over the area of interest. After contacting the hands of the shooter, or other surfaces, the swab simply has solvent applied to the rayon tip and a high voltage applied to the aluminum handle. This process generates ions that the mass spectrometer will use to determine if the organic gunshot residues are present. Mass spectrometry allows for the direct confirmation of organic gunshot residue on suspects hands, confirmed through tandem mass spectrometry. Additional benefits of swab touch spray ionization are that the swabs are commercially available, they are sterile, and they are individually packaged to prevent contamination. The swabs are also forensically feasible because they are sealed prior to delivery by the vendor with a tamper-proof label. Here we have shown that this ambient ionization method allows for the direct swabbing of suspected shooters hands for trace residues and confirm the presence of the two organic gunshot residues investigated.

Rapid mass spectrometry analysis of a rectilinear ion trap by continuous secular frequency scanning.

Secular frequency scanning is a mass spectrometry (MS) analysis method in which the frequency of the auxiliary alternating current (AC) signal is scanned. It has low requirements for radio-frequency (RF) power, which is beneficial for the miniaturization of the mass spectrometer. In this study, the MS performance in the reverse secular frequency scanning (RSFS) mode is optimized for a rectilinear ion trap (RIT), and a method for rapid MS analysis using continuous secular frequency scanning (CSFS) is proposed. A RIT mass spectrometer with an auxiliary AC frequency scanning function was built. The resolution, tandem mass spectrometry (MS/MS) and quantitation capability in the RSFS mode were characterized and optimized. Operation in the CSFS mode was then performed by scanning the frequency of the auxiliary AC signal continuously and periodically while maintaining the RF signal and the front Z electrode in the ion injection state, so that the ion injection and cooling were performed at the same time as the mass analysis. With this system, the RSFS mode achieved unit mass resolution at 332 Th, and the MS/MS analysis was completed without changing the RF amplitude at q=0.4583 for reserpine. The limit of quantitation for imatinib was about 250ng/mL with the determination coefficient R2 =0.9981. In the CSFS mode, a single analysis cycle of less than 20ms could be achieved, which is 14 times faster than the traditional sweep modes. In addition, 100% ion utilization can theoretically be achieved in the CSFS mode. The CSFS mode is different from the traditional phased sequential operation mode of an ion trap mass spectrometer. By periodic scanning of the auxiliary AC frequency while maintaining ion injection, it is possible to improve the analysis efficiency of the mass spectrometer, which has the prospect of useful application in the field of rapid MS monitoring. Copyright © 2017 John Wiley & Sons, Ltd.

Slug-flow microextraction coupled with paper spray mass spectrometry for rapid analysis of complex samples

Analysis of trace compounds in small-volume complex samples is of importance for forensic, clinical, pharmaceutical, environmental, and life science investigation. In this study, we reported the coupling of slug-flow microextraction with paper spray mass spectrometry for rapid analysis of trace analytes in small volume of complicated biological samples such as whole blood, milk, and body fluid, etc. The method is performed by applying a disposable glass capillary for rapid extraction of a small amount of complex samples using a small amount of organic solvent; the loaded organic solvent was then spotted onto a paper triangle and dried out; subsequently, a high voltage and some spray solvent were applied onto the paper triangle for mass spectrometric analysis. By using the proposed method, high sensitivity and satisfactory precision for quantitative analysis of trace macrolide antibiotics in whole bloods and milks as well as perfluorinated compounds in individual small organisms have been successfully achieved. In addition, investigation of bioaccumulation of perfluorinated compounds in individual small organisms has been reached.

Ultra-High Performance Liquid Chromatography—Tandem Mass Spectrometry for Rapid Analysis of Seven Phenolic Compounds of Sparganii Rhizoma

The rhizome of Sparganium stoloniferum Buch.-Ham has been used as a traditional Chinese folk medicine for thousands of years. Phenolic compounds are the main bioactive ingredients of the plant. In order to determine the content of phenolic compounds from different major cultivations, a reliable method has been developed using ultra-high performance liquid chromatography coupled with a triple quadrupole electrospray tandem mass spectrometry. Seven compounds, including rutin, kaempferol, p-hydroxybenzaldehyde, formononetin, ferulic acid, vanillic acid, and p-coumaric acid, were simultaneously measured in 10 min. The established approach was fully validated in terms of linearity, sensitivity, precision, repeatability as well as recovery, and successfully applied to determine seven phenolic compounds of Rhizoma Sparganii. This study may be helpful in the quality control of Rhizoma Sparganii and can offer technical support for the pharmacological and clinical study of related drugs.

A silica coated paper substrate: development and its application in paper spray mass spectrometry for rapid analysis of pesticides in milk.

A novel silica coated paper substrate is developed through a facile vacuum filtration method by using the commercially available silica particles as the coating material and corn starch as the adhesive agent. Unlike the commercial silica coated paper (namely grade SG81 paper), the resulting paper substrate was covered by a layer of silica particles on the top side of the paper, and no cellulosic fibers were exposed at its surface. After loading a solution sample on its surface, the coated silica particles allowed the target analytes to remain at the top side rather than penetration through the substrate. Owing to this effect and the special interactions with analytes, the as-prepared silica coated paper demonstrated superior performance in the analysis of different pesticides in milk using paper spray mass spectrometry to the uncoated filter paper and grade SG81 paper. Compared to the other two papers, paper spray analysis using the as-prepared paper improved the estimated lower limit of quantitation of seven pesticides (alachlor, acetochlor, pretilachlor, butachlor, metolachlor, napropamid and benzeneacetamide) in milk by a factor of 2 to 19-fold depending on the pesticide. This study offers a novel paper substrate for paper spray in high sensitivity analysis of target analytes in a complex foodstuff matrix without any pretreatment.

Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry for rapid analysis of the metabolites of morroniside produced by human intestinal bacteria

Morroniside, the most abundant iridoid glycoside in the valuable traditional Chinese medicine Fructus Corni, exhibits various pharmacological activities and biological effects. Intestinal flora plays an important role in the metabolism of drug compounds, which might lead to the variation of ethnopharmacological profile of the medicine. However, little is known of the interactions of the morroniside with human intestinal bacteria. In this study, different pure bacteria were isolated from human feces and their capability to convert morroniside were investigated. The metabolites of morroniside were analyzed by ultra high performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) technique using Metabolynx™ software. Parent compound and three metabolites were detected and tentatively identified based on the characteristics of their protonated ions. The parent is proposed to be metabolized by three main metabolic pathways including deglycosylation, dehydroxylation and methylation. Morroniside was firstly metabolized to its aglycone (M1), and then was further converted to dehydroxylated aglycone (M2) and methylated aglycone (M3). This is the first report of the metabolism of morroniside by human intestinal bacteria. These metabolites might influence the biological activities of morroniside in vivo, which could affect the clinical effects of medicines. Thus, the study on the metabolism of morroniside by human intestinal bacteria is very helpful to unravel how traditional medicines work.

Droplet electrospray ionization mass spectrometry for high throughput screening for enzyme inhibitors.

High throughput screening (HTS) is important for identifying molecules with desired properties. Mass spectrometry (MS) is potentially powerful for label-free HTS due to its high sensitivity, speed, and resolution. Segmented flow, where samples are manipulated as droplets separated by an immiscible fluid, is an intriguing format for high throughput MS because it can be used to reliably and precisely manipulate nanoliter volumes and can be directly coupled to electrospray ionization (ESI) MS for rapid analysis. In this study, we describe a “MS Plate Reader” that couples standard multiwell plate HTS workflow to droplet ESI-MS. The MS plate reader can reformat 3072 samples from eight 384-well plates into nanoliter droplets segmented by an immiscible oil at 4.5 samples/s and sequentially analyze them by MS at 2 samples/s. Using the system, a label-free screen for cathepsin B modulators against 1280 chemicals was completed in 45 min with a high Z-factor (>0.72) and no false positives (24 of 24 hits confirmed). The assay revealed 11 structures not previously linked to cathepsin inhibition. For even larger scale screening, reformatting and analysis could be conducted simultaneously, which would enable more than 145 000 samples to be analyzed in 1 day.

Immunoproteomics Using Polyclonal Antibodies and Stable Isotope–labeled Affinity-purified Recombinant Proteins

The combination of immuno-based methods and mass spectrometry detection has great potential in the field of quantitative proteomics. Here, we describe a new method (immuno-SILAC) for the absolute quantification of proteins in complex samples based on polyclonal antibodies and stable isotope-labeled recombinant protein fragments to allow affinity enrichment prior to mass spectrometry analysis and accurate quantification. We took advantage of the antibody resources publicly available from the Human Protein Atlas project covering more than 80% of all human protein-coding genes. Epitope mapping revealed that a majority of the polyclonal antibodies recognized multiple linear epitopes, and based on these results, a semi-automated method was developed for peptide enrichment using polyclonal antibodies immobilized on protein A-coated magnetic beads. A protocol based on the simultaneous multiplex capture of more than 40 protein targets showed that approximately half of the antibodies enriched at least one functional peptide detected in the subsequent mass spectrometry analysis. The approach was further developed to also generate quantitative data via the addition of heavy isotope-labeled recombinant protein fragment standards prior to trypsin digestion. Here, we show that we were able to use small amounts of antibodies (50 ng per target) in this manner for efficient multiplex analysis of quantitative levels of proteins in a human HeLa cell lysate. The results suggest that polyclonal antibodies generated via immunization of recombinant protein fragments could be used for the enrichment of target peptides to allow for rapid mass spectrometry analysis taking advantage of a substantial reduction in sample complexity. The possibility of building up a proteome-wide resource for immuno-SILAC assays based on publicly available antibody resources is discussed.

Coupling Micropipette Tipbased Microextraction with Desorption Corona Beam Ionization Mass Spectrometry for Rapid Analysis of Antihypertensive Drugs in Body Fluid

Coupling Micropipette Tipbased Microextraction with Desorption Corona Beam Ionization Mass Spectrometry for Rapid Analysis of Antihypertensive Drugs in Body Fluid

Using Mass Spectrometry To Identify and Characterize Bacteria

Rapid, accurate, and cost-effective approaches to characterizing bacteria are of profound interest and high value to clinical, medical, and environmental microbiologists. One such approach, mass spectrometry (MS), evolved quickly during the past decade, complementing and in some instances surpassing other, more conventional but also time- and labor-intensive approaches for characterizing bacteria and other microorganisms. Whereas biochemical analyses that depend on metabolic reactions or PCR might require hours or days to complete, MS analysis can yield data in minutes. Rapid MS analysis is being applied to a remarkably diverse array of bacteria with agricultural, medical, clinical, and environmental significance. Further, commercially available MS systems are beginning to receive regulatory approval for use in diagnostic and clinical settings in the United States, Europe, and elsewhere.

Ultra‐performance liquid‐chromatography with tandem mass spectrometry for rapid analysis of pharmacokinetics, biodistribution and excretion of schisandrin after oral administration of Shengmaisan

This study aimed to investigate the in vivo behaviors of the main components in traditional Chinese medicine (TCM) fomulae. The plasma pharmacokinetics, tissue distribution and excretion of the main component-schisandrin in rats after oral administration of a classical TCM prescription, shengmaisan (SMS), were studied by a developed and validated UPLC-MS/MS method. The separation of schisandrin was achieved on a UPLC HSS T3 column with a mobile phase consisting of acetonitrile and water at a flow rate of 0.5 mL/min by linear gradient elution. The MS/MS detection was carried out by monitoring the fragmentation of m/z 415.22 → 384.26 for schisandrin on a triple quadrupole mass spectrometer. The result showed that the method was suitable for the quantification of schisandrin in plasma, tissue and excreta samples with satisfactory selectivity, precision, accuracy, sensitivity, linearity and recovery. Pharmacokinetic results showed a rapid absorption phase with the mean Tmax of 0.17 h and a relatively slow elimination proceeding with a half-life (T1/2 ) of 5.24 ± 1.28 h. The tissue distribution showed the maximum concentration distributions of schisandrin after oral administration of SMS were in the order of small intestine > large intestine > lung > liver > kidney > spleen > heart > brain. Only 0.005-0.006% of schisandrin was recovered in feces and was not detected in urine.

Ultra high performance liquid chromatography tandem mass spectrometry for rapid analysis of trace organic contaminants in water

BackgroundThe widespread utilization of organic compounds in modern society and their dispersion through wastewater have resulted in extensive contamination of source and drinking waters. The vast majority of these compounds are not regulated in wastewater outfalls or in drinking water while trace amounts of certain compounds can impact aquatic wildlife. Hence it is prudent to monitor these contaminants in water sources until sufficient toxicological data relevant to humans becomes available. A method was developed for the analysis of 36 trace organic contaminants (TOrCs) including pharmaceuticals, pesticides, steroid hormones (androgens, progestins, and glucocorticoids), personal care products and polyfluorinated compounds (PFCs) using a single solid phase extraction (SPE) technique with ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The method was applied to a variety of water matrices to demonstrate method performance and reliability.ResultsUHPLC-MS/MS in both positive and negative electrospray ionization (ESI) modes was employed to achieve optimum sensitivity while reducing sample analysis time (<20 min) compared with previously published methods. The detection limits for most compounds was lower than 1.0 picogram on the column while reporting limits in water ranged from 0.1 to 15 ng/L based on the extraction of a 1 L sample and concentration to 1 mL. Recoveries in ultrapure water for most compounds were between 90-110%, while recoveries in surface water and wastewater were in the range of 39-121% and 38-141% respectively. The analytical method was successfully applied to analyze samples across several different water matrices including wastewater, groundwater, surface water and drinking water at different stages of the treatment. Among several compounds detected in wastewater, sucralose and TCPP showed the highest concentrations.ConclusionThe proposed method is sensitive, rapid and robust; hence it can be used to analyze a large variety of trace organic compounds in different water matrixes.

Sample preparation and direct electrospray ionization on a tip column for rapid mass spectrometry analysis of complex samples

A handheld pipette tip column electrospray ionization source (PTC-ESI source) was developed for rapid mass spectrometry analysis at ambient pressure. The PTC-ESI source was made up of three main component parts including a micro DC high voltage (HV) power supply, a micropipette and a disposable micropipette tip filled with a plug of adsorbent. A DC high voltage was applied to the sharp point of the micropipette tip column to induce electrospray ionization. The PTC-ESI source was successfully used for direct analysis of basic organic compounds, organic acids and peptides in a simple matrix. In the case of complex samples, micro-extraction based on the adsorbent phase filled in the pipette tip was used to remove impurities and concentrate target analytes prior to ionization. The eluting solution was not pipetted out, but directly dispersed in the form of electrospray from the pipette tip for ionization. The effectiveness of the PTC-ESI source has been further demonstrated by fast analysis of therapeutic compounds and endogenous bioactive chemicals in complex biological samples.