Sequential Injection Analysis Method for the Determination of Glutathione in Pharmaceuticals.

A sequential injection analysis method for the determination of glutathione (GSH) in pharmaceuticals has been developed. It is based on the reduction of the Cu(II)-neocuproine complex by GSH and the formation of an orange-yellow colored Cu(I)-neocuproine complex with maximum absorbance at 458 nm. Under optimal conditions the method is characterized by a linear calibration range of 6.0 × 10-7-8.0 × 10-5 mol L-1 (Amax = 3270 CGSH - 0.0010; R2 = 0.9983), limit of detection of 2.0 × 10-7 mol L-1, limit of quantification of 6.7 × 10-7 mol L-1, repeatability (expressed as relative standard deviation) of 3.8%, and sampling rate of 60 h-1. The newly developed method has been successfully applied to the determination of GSH in pharmaceutical samples with no statistically significant difference between the results obtained and those produced by the standard Pharmacopoeia method.

Precise evaluation of batch adsorption kinetics of plant total polyphenols based on a flow-injection online spectrophotometric method.

Efficient evaluation of adsorption kinetics of plant total polyphenols is essential for the design of adsorption separation of bioactive compounds. The conventional method uses manual sampling with poor reproducibility. Here, we developed a new method for on-line determination of total polyphenol content (TPC) in plant extracts by applying the Folin-Ciocalteu method in flow-injection analysis (FIA). The FIA parameters were optimized and a standard curve with excellent linearity was established. Precise determination of TPC with a satisfactory sample throughput of 20 h-1 was achieved for the adsorption kinetic study. The pseudo-second-order kinetic model was found to better describe the kinetic parameters of the batch adsorption/desorption process. The developed method proved to be accurate compared with the conventional method. The FIA method holds significant promise for studying and monitoring adsorption processes, due to its automatic on-line nature, low consumption of reagents and samples, and the ability to generate large quantities of highly accurate adsorption data.

Non-enzymatic glucose sensing using a nickel hydroxide/chitosan modified screen-printed electrode incorporated into a flow injection analysis system.

This works presents a novel screen-printed carbon electrode modified with nickel hydroxide nanoparticles and chitosan (Ni(OH)2/CS/SPCE) for the non-enzymatic flow injection amperometric detection of glucose. The electrode was modified by drop-casting a suspension of the synthesised nanocomposite onto the screen-printed electrode and dried for 1 hour at room temperature. EDX analysis was used to investigate the chemical composition of the electrode before and after modifying. The electrochemical response of the unmodified SPCE and modified electrode was initially investigated by cyclic voltammetry (CV) using 0.1 M NaOH as the supporting electrolyte. CVs showed catalytic activity for glucose oxidation using the Ni(OH)2/CS/SPCE at 0.55 V. During flow injection analysis (FIA), 0.60 V and 1.5 mL min-1 were identified as the optimal potential and flow rate, respectively. A wide linear range of detection was observed (0.2 to 10.0 mM) with a sensitivity and limit of detection of 913 µA mM-1 cm-2 and 0.0174 mM, respectively. The modified electrode also displayed excellent repeatability (RSD = 0.47%, n = 20) and good reproducibility (RSD = 2.52%, n = 6). The modified electrode was shown to be very selectivity for glucose over other interferences commonly found in human blood samples. The practicality of the developed flow injection-amperometric system (FIA-Amp) was validated by the quantification of glucose in real serum samples, where results were in close agreement with those obtained from the local hospital.

Glassy Carbon Electrode Modified with CB/TiO2 Layer for Sensitive Determination of Sumatriptan by Means of Voltammetry and Flow Injection Analysis.

Sumatriptan is an organic chemical compound from the tryptamine group. It is used as a medicine for migraine attacks and in the treatment of cluster headaches. In this work, a new voltammetric method is proposed for highly sensitive SUM determination, using glassy carbon electrodes modified with carbon black and titanium dioxide suspension. The novelty of the presented work is the usage of the mixture of carbon black and TiO2 as glassy carbon electrode modifier for the first time for SUM determination. The mentioned sensor was characterized by great repeatability and sensitivity of measurements, which resulted in the obtention of a wide range of linearity and a low detection limit. The electrochemical properties of the CB-TiO2/GC sensor was characterized using the LSV and EIS method. The effect of different factors on the SUM peak, such as supporting electrolyte type, preconcentration time and potential, or influence of interferents, were tested using the square wave voltammetry technique. The linear voltammetric response for the analyte was obtained in the concentration range of 5 nmol L-1 to 150 µmol L-1 with a detection limit of 2.9 nmol L-1 for a preconcentration time of 150 s in the 0.1 mol L-1 phosphate buffer pH 6.0. The proposed method was successfully applied for highly sensitive sumatriptan determination in complex matrices, such as tablets, urine, and plasma, with a good recovery parameter (94-105%). The presented CB-TiO2/GC electrode is characterized by great stability, it was used for 6 weeks without significant changes in the SUM peak current. Amperometric and voltammetric measurements of SUM under the flow injection conditions were also performed to indicate the possibility of its fast and accurate determination with a time of single analysis of approx. 30 s.

Multiplexing Homocysteine into First-Tier Newborn Screening Mass Spectrometry Assays Using Selective Thiol Derivatization.

BACKGROUND: Classical homocystinuria (HCU) results from deficient cystathionine ß-synthase activity, causing elevated levels of Met and homocysteine (Hcy). Newborn screening (NBS) aims to identify HCU in pre-symptomatic newborns by assessing Met concentrations in first-tier screening. However, unlike Hcy, Met testing leads to a high number of false-positive and -negative results. Therefore, screening for Hcy directly in first-tier screening would be a better biomarker for use in NBS. METHODS: Dried blood spot (DBS) quality control and residual clinical specimens were used in analyses. Several reducing and maleimide reagents were investigated to aid in quantification of total Hcy (tHcy). The assay which was developed and validated was performed by flow injection analysis-tandem mass spectrometry (FIA-MS/MS). RESULTS: Interferents of tHcy measurement were identified, so selective derivatization of Hcy was employed. Using N-ethylmaleimide (NEM) to selectively derivatize Hcy allowed interferent-free quantification of tHcy by FIA-MS/MS in first-tier NBS. The combination of tris(2-carboxyethyl)phosphine (TCEP) and NEM yielded significantly less matrix effects compared to dithiothreitol (DTT) and NEM. Analysis of clinical specimens demonstrated that the method could distinguish between HCU-positive, presumptive normal newborns, and newborns receiving total parenteral nutrition. CONCLUSIONS: Here we present the first known validated method capable of screening tHcy in DBS during FIA-MS/S first-tier NBS.

Robust and high-throughput lipidomic quantitation of human blood samples using flow injection analysis with tandem mass spectrometry for clinical use.

Direct infusion of lipid extracts into the ion source of a mass spectrometer is a well-established method for lipid analysis. In most cases, nanofluidic devices are used for sample introduction. However, flow injection analysis (FIA) based on sample infusion from a chromatographic pump can offer a simple alternative to shotgun-based approaches. Here, we describe important modification of a method based on FIA and tandem mass spectrometry (MS/MS). We focus on minimizing contamination of the FIA/MS both to render the lipidomic platform more robust and to increase its capacity and applicability for long-sequence measurements required in clinical applications. Robust validation of the developed method confirms its suitability for lipid quantitation in human plasma analysis. Measurements of standard human plasma reference material (NIST SRM 1950) and a set of plasma samples collected from kidney cancer patients and from healthy volunteers yielded highly similar results between FIA-MS/MS and ultra-high-performance supercritical fluid chromatography (UHPSFC)/MS, thereby demonstrating that all modifications have practically no effect on the statistical output. Newly modified FIA-MS/MS allows for the quantitation of 141 lipid species in plasma (11 major lipid classes) within 5.7 min. Finally, we tested the method in a clinical laboratory of the General University Hospital in Prague. In the clinical setting, the method capacity reached 257 samples/day. We also show similar performance of the classification models trained based on the results obtained in clinical settings and the analytical laboratory at the University of Pardubice. Together, these findings demonstrate the high potential of the modified FIA-MS/MS for application in clinical laboratories to measure plasma and serum lipid profiles.

Determination of pioglitazone hydrochloride by flow injection chemiluminescence tris(2,2'-bipyridyl)ruthenium(II)-silver(III) complex system.

A novel flow injection-chemiluminescence (FI-CL) approach is proposed for the assay of pioglitazone hydrochloride (PG-HCl) based on its enhancing influence on the tris(2,2'-bipyridyl)ruthenium(II)-silver(III) complex (Ru(bipy)3 2+ -DPA) CL system in sulfuric acid medium. The possible CL reaction mechanism is discussed with CL and ultraviolet (UV) spectra. The optimum experimental conditions were found as: Ru(bipy)3 2+ , 5.0 × 10-5  M; sulfuric acid, 1.0 × 10-3  M; diperiodatoargentate(III) (DPA), 1.0 × 10-4  M; potassium hydroxide, 1.0 × 10-3  M; flow rate 4.0 ml min-1 for each flow stream and sample loop volume, 180 µl. The CL intensity of PG-HCl was linear in the range of 1.0 × 10-3 to 5.0 mg L-1 (R2 = 0.9998, n = 10) with limit of detection [LOD, signal-to-noise ratio (S/N) = 3] of 2.2 × 10-4  mg L-1 , limit of quantification (LOQ, S/N = 10) of 6.7 × 10-4  mg L-1 , relative standard deviation (RSD) of 1.0 to 3.3% and sampling rate of 106 h-1 . The methodology was satisfactorily used to quantify PG-HCl in pharmaceutical tablets with recoveries ranging from 93.17 to 102.77 and RSD from 1.9 to 2.8%.

Photometric flow injection analysis of As(III) by using a homemade, LED-based flow-cell device and methyl orange reagent.

Inorganic arsenic especially As(III) is considered a carcinogenic substance and its measurement is important in water samples. In this work, an inexpensive flow injection analysis system was designed for the photometric determination of As(III) at low concentrations. For this purpose, a light-emitting diode (LED) based photometer with a miniaturized detector, was fabricated and used as a determination apparatus and methyl orange was used as a detecting reagent. The fabricated photometer employed the LEDs, as a light source and the light detector. The λmax of emission for emitter and detector LEDs were 525 and 625 nm, respectively. Determination of As (III) was based on its inhibition effect on the redox reaction between methyl orange and X2 (Cl2 or Br2). The decolorization of the reaction products in the FIA system was monitored using the homemade flow cell detector. Analytical figures of merit including linear responses ranging from 0.03 to 3.0 mg/l of As(III) (r = 0.994), detection limits of 0.007 mg/l As(III), RSD% of 1.5% (n = 7), low reagent consumption per determination, and sampling throughput of 50 determinations per hour were achieved.

The Determination Method of Total Polyphenol in Tea and Substitute Tea Based on [Ag(HIO6)2]5--Luminol Chemiluminescence System.

BACKGROUND: Scientific, accurate, and rapid detection of the composition and content of tea polyphenols is an important basis for their rational use and giving full play to their physiological effect. The spectrophotometric assays for total polyphenols have poor selectivity. Therefore, there is a need to develop a simple and reliable method for the determination of the total polyphenolic level in tea products. OBJECTIVE: The aim of this research was to develop a flow injection chemiluminescence (FI-CL) method based on the Ag(III)-luminol system for the total polyphenol content analysis of tea and substitute tea. METHOD: Through Box-Behnken experimental design, we selected the optimum determination condition. The Ag(III) concentration was 5 × 10-5 mol/L, and the luminol concentration was 3 × 10-7 mol/L (including 0.15 mol/L NaOH). The peristaltic pump is 25 r/min, and the photomultiplier voltage is 600 v. Sample extracts were diluted 100 000 times for the FI-CL assay. RESULTS: Under optimal conditions, CL intensities were proportional to total polyphenol content (in terms of gallic acid concentrations) in the range of 0.1∼100 µg/L. The LOD and LOQ were 0.03 µg/L and 0.1 µg/L. The recovery values were in the range of 86.3-111.0% with a RSD of 1.04∼2.62%. The polyphenolic content of 12 teas and 6 substitute teas was determined, and the results of the developed method and Folin-Ciocalteu method were highly correlated (r = 0.9493 for tea and r = 0.8533 for substitute tea). CONCLUSIONS: The proposed method is better than the Folin-Ciocalteu method in terms of selectivity, sensitivity, and accuracy. It is suitable for the determination of polyphenol content not only in tea, but also in substitute tea. HIGHLIGHTS: We developed a new flow-injection analysis method for polyphenolic content determination based on the Ag(III)-luminol chemiluminescence system. It is simple, rapid, sensitive, and accurate. It is suitable for the determination of polyphenols content not only in tea, but also in substitute tea.

Nickel oxide hollow microsphere for the chemiluminescence determination of tuberculostatic drug isoniazid.

In this article, nickel(II) oxide (NiO) hollow microspheres (HMSs) were fabricated and used to catalyze chemiluminescence (CL) reaction. The studied CL reaction is the luminol-oxygen reaction that was used as a sensitive analytical tool for measuring tuberculostatic drug isoniazid (IND) in pharmaceutical formulations and water samples. The CL method was established based on the suppression impact of IND on the CL reaction. The NiO HMSs were produced by a simple hydrothermal method and characterized by several spectroscopic techniques. The result of essential parameters on the analytical performance of the CL method, including concentrations of sodium hydroxide (NaOH), luminol, and NiO HMSs were investigated. At the optimum conditions, the calibration curve for IND was linear in the range of 8.00 × 10-7 to 1.00 × 10-4  mol L-1 (R2  = 0.99). A detection limit (3S) of 2.00 × 10-7  mol L-1 was obtained for this method. The acceptable relative standard deviation (RSD) was obtained for the proposed CL method (2.63%, n = 10) for a 5.00 × 10-6  mol L-1 IND solution. The mechanism of the CL reaction was also discussed.

FIA-HRMS fingerprinting subjected to chemometrics as a valuable tool to address food classification and authentication: Application to red wine, paprika, and vegetable oil samples.

The rise of food fraud practices, affecting a wide variety of goods and their specific characteristics (e.g., quality or geographical origin), demands rapid high-throughput analytical approaches to ensure consumers protection. In this context, this study assesses flow injection analysis coupled to high-resolution mass spectrometry (FIA-HRMS), using a fingerprinting approach and combined with chemometrics, to address four food authentication issues: (i) the geographical origin of three Spanish red wines, (ii) the geographical origin of three European paprikas, (iii) the distinction of olive oil from other vegetable oils and (iv) the assessment of its quality category. In each case, negative and positive ionisation FIA-HRMS fingerprints, and two different data fusion strategies, were evaluated. After external validation, excellent classification accuracies were reached. Moreover, high-resolution mass spectrometry (HRMS) allowed sample matrices characterisation by the putative identification of the most common ions.

A DMS Shotgun Lipidomics Workflow Application to Facilitate High-Throughput, Comprehensive Lipidomics.

Differential mobility spectrometry (DMS) is highly useful for shotgun lipidomic analysis because it overcomes difficulties in measuring isobaric species within a complex lipid sample and allows for acyl tail characterization of phospholipid species. Despite these advantages, the resulting workflow presents technical challenges, including the need to tune the DMS before every batch to update compensative voltages settings within the method. The Sciex Lipidyzer platform uses a Sciex 5500 QTRAP with a DMS (SelexION), an LC system configured for direction infusion experiments, an extensive set of standards designed for quantitative lipidomics, and a software package (Lipidyzer Workflow Manager) that facilitates the workflow and rapidly analyzes the data. Although the Lipidyzer platform remains very useful for DMS-based shotgun lipidomics, the software is no longer updated for current versions of Analyst and Windows. Furthermore, the software is fixed to a single workflow and cannot take advantage of new lipidomics standards or analyze additional lipid species. To address this multitude of issues, we developed Shotgun Lipidomics Assistant (SLA), a Python-based application that facilitates DMS-based lipidomics workflows. SLA provides the user with flexibility in adding and subtracting lipid and standard MRMs. It can report quantitative lipidomics results from raw data in minutes, comparable to the Lipidyzer software. We show that SLA facilitates an expanded lipidomics analysis that measures over 1450 lipid species across 17 (sub)classes. Lastly, we demonstrate that the SLA performs isotope correction, a feature that was absent from the original software.

Multicommutated Flow Analysis System for Determination of Horseradish Peroxidase and Its Inhibitors.

A fully mechanized multicommutated flow analysis (MCFA) system dedicated to determining horseradish peroxidase (HRP) activity was developed. Detection was conducted using a flow-through optoelectronic detector-constructed of paired LEDs operating according to the paired emitter-detector diode (PEDD) principle. The PEDD-MCFA system is dedicated to monitoring the enzyme-catalyzed oxidation of p-phenylenediamine (pPD) by a hydrogen peroxide. Under optimized conditions, the presented bioanalytical system was characterized by a linear response range (33.47-200 U/L) with a detection limit at 10.54 U/L HRP activity and 1.66 mV·L/U sensitivity, relatively high throughput (12 signals recordings per hour), and acceptable precision (RSD below 6%). Additionally, the utility of the developed PEDD-MCFA system for the determination of HRP inhibitors allowing the detection of selected thiols at micromolar levels, is demonstrated. The practical utility of the flow system was illustrated by the analysis of some dietary supplements containing L-cysteine, N-acetylcysteine, and L-glutathione.

Photometric Determination of Iron in Pharmaceutical Formulations Using Double-Beam Direct Injection Flow Detector.

In this work, an innovative, flow-through, double-beam, photometric detector with direct injection of the reagents (double-DID) was used for the first time for the determination of iron in pharmaceuticals. For stable measurement of the absorbance, double paired emission-detection LED diodes and a log ratio precision amplifier have been applied. The detector was integrated with the system of solenoid micro-pumps. The micro-pumps helped to reduce the number of reagents used and are responsible for precise solution dispensing and propelling. The flow system is characterized by a high level of automation. The total iron was determined as a Fe(II) with photometric detection using 1,10-phenanthroline as a complexing agent. The optimum conditions of the propose analytical procedure were established and the method was validated. The calibration graph was linear in the range of 1 to 30 mg L-1. The limit of detection (LOD) was 0.5 mg L-1. The throughput of the method was 90 samples/hour. The repeatability of the method expressed as the relative standard deviation (R.S.D.) was 2% (n = 10). The method was characterized by very low consumption of reagents and samples (20 µL each) and a small amount of waste produced (about 540 µL per analysis). The proposed flow method was successfully applied for determination of iron in pharmaceutical products. The results were in good agreement with those obtained using the manual UV-Vis spectrophotometry and with values claimed by the manufacturers. The flow system worked very stably and was insensitive to bubbles appearing in the system.

Electrochemical flow injection analysis of the interaction between pyrroloquinoline quinone (PQQ) and α-synuclein peptides related to Parkinson's disease.

α-Synuclein (α-syn) is a hallmark protein of Parkinson's disease (PD). The aggregation process of α-syn has been heavily associated with the pathogenesis of PD. With the exponentially growing number of potential therapeutic compounds that can inhibit the aggregation of α-syn, there is now a significant demand for a high-throughput analysis system. Herein, a novel flow injection analysis system with an electrochemical biosensor as the detector was developed to study the interaction of a well-described antioxidant and amyloid inhibitor, pyrroloquinoline quinone (PQQ) with α-synuclein peptides. Screen-printed gold electrodes (SPEs) were modified using heptapeptides from α-syn wild-type (WT) and mutants such as lysine knock-out (ETEE) and E46K. Affinity binding events between these peptides and PQQ were analyzed by electrochemical impedance spectroscopy (EIS) and further confirmed by high-performance liquid chromatography (HPLC), liquid chromatography/mass spectrometry (LC/MS), and nuclear magnetic resonance (NMR) spectroscopy. HPLC and LC/MS results revealed that PQQ formed a stable complex with α-syn. NMR results confirmed that the α-syn-PQQ complex was formed via a Schiff base formation-like process. In addition, results showed that lysine residues influenced the binding event, in which the presence of an extra lysine stabilized the α-syn-PQQ complex, and the absence of a lysine significantly decreased the interaction of α-syn with PQQ. Therefore, we concluded that EIS is a promising technique for the evaluation of the interaction between PQQ-based amyloid inhibitors and α-syn. The electrochemical flow injection analysis assembly provided a rapid and low-cost drug discovery platform for the evaluation of small molecule-protein interactions.

Mass spectrometry in the study of molecular complexes between 5-fluorouracil and catechins.

5-Fluorouracil (5FU) is a widely employed antineoplastic agent that acts as antimetabolite. However, 5FU activity is strongly reduced against a subset of cancer cells called cancer stem cells (CSCs), which are believed to be responsible for chemoresistance and tumour recurrence. It was found that epigallocatechin-3-gallate (EGCG), the most abundant catechin present in green tea extract, suppresses CSCs grown in various cancers. This chemosensitizing effect of EGCG was investigated in 5FU-resistant (5FUR) CRC cells, showing that EGCG enhances 5FU-induced cytotoxicity. However, the real mechanism of an improved 5FU chemosensitivity in the presence of EGCG was not evaluated. Considering the capability of catechins to form bimolecular noncovalent complexes, in the present study, the interaction of catechins and 5FU was studied by different mass spectrometric approaches. The ESI(+) and ESI(-) spectra of [5FU-catechin] mixtures were studied, showing the formation of protonated and deprotonated bimolecular complexes, whose nature was confirmed by MS/MS experiments (product and precursor ion scans). To exclude the possible origin of these species as ESI artefacts, a further series of experiments were performed by high-resolution liquid chromatography-mass spectrometry. By this approach, bimolecular complexes have been detected at retention times different from those of free 5FU and catechins, proving their presence in the original solution. Analogous studies were performed on 5FU-green tea extract mixtures, showing that 5FU leads to complexes not only with EGCG but also with other catechins. These molecular species, differently to free 5FU drug alone, would in principle possess a new biological activity and could be an explanation of the described activity cited above.

Development of glycated peptide enzyme sensor based flow injection analysis system for haemoglobin A1c monitoring using quasi-direct electron transfer type engineered fructosyl peptide oxidase.

Haemoglobin A1c (hemoglobin A1c, HbA1c) is an important long-term glycemic control marker for diabetes. The aim of this study was to develop an enzyme flow injection analysis (FIA) system using engineered fructosyl peptide oxidase (FPOx) based on 2.5th generation principle for an HbA1c automated analytical system. FPOx from Phaeosphaeria nodorum (PnFPOx) was engineered by introducing a Lys residue at the R414 position, to be modified with amine reactive phenazine ethosulfate (arPES) in proximity of FAD. The engineered PnFPOx mutant with minimized oxidase activity, N56A/R414K, showed quasi-direct electron transfer (quasi-DET) ability after PES-modification. The FIA system was constructed by employing a PES-modified PnFPOx N56A/R414K and operated at 0 V against Ag/AgCl. The system showed reproducible responses with a linear range of 20-500 µM for both fructosyl valine (FV) and fructosyl valylhistidine (FVH), with sensitivities of 0.49 nA µM-1 and 0.13 nA µM-1, and the detection limits of 1.3 µM and 2.0 µM for FV and FVH, respectively. These results indicate that the enzyme electrochemical FIA system covers the clinical range of HbA1c detection for more 200 consecutive measurements. Protease digested three different levels of HbA1c samples including healthy and diabetic range subjects were also measured with the FIA system. Thus, it will be possible to develop an integrated system consisting of sample pretreatment and sample electrochemical measurement based on an FIA system possessing quasi-DET type PnFPOx.

Olive Oil Quality and Authenticity Assessment Aspects Employing FIA-MRMS and LC-Orbitrap MS Metabolomic Approaches.

Edible vegetable oils comprise integral components of humans' daily diet during the lifetime. Therefore, they constitute a central part of dietary-exposome, which among other factors regulates human health. In particular, the regular consumption of olive oil (OO) has been largely accepted as a healthy dietary pattern. Responsible for its recognition as a superior edible oil is its exceptional aroma and flavor. Its unique composition is characterized by high levels of monounsaturated fatty acids and the presence of minor constituents with important biological properties, such as the so-called OO polyphenols. Being a high added value product, OO suffers from extensive fraud and adulteration phenomena. However, its great chemical complexity, variability, and the plethora of parameters affecting OO composition hamper significantly the selection of the absolute criteria defining quality and authenticity, and a reliable and robust methodology is still unavailable. In the current study, Flow Injection Analysis-Magnetic Resonance Mass Spectrometry (FIA-MRMS) was investigated under a metabolic profiling concept for the analysis of Greek Extra Virgin Olive Oils (EVOO). More than 200 monovarietal (Koroneiki) EVOO samples were collected from the main Greek OO producing regions and investigated. Both intact oil and the corresponding polyphenols were analyzed in fast analysis time of 2 and 8 min, respectively. In parallel, an LC-Orbitrap MS platform was used to verify the efficiency of the method as well as a tool to increase the identification confidence of the proposed markers. Based on the results, with FIA-MRMS, comparable and improved projection and prediction models were generated in comparison to those of the more established LC-MS methodology. With FIA-MRMS more statistically significant compounds and chemical classes were identified as quality and authenticity markers, associated with specific parameters, i.e. geographical region, cultivation practice, and production procedure. Furthermore, it was possible to monitor both lipophilic and hydrophilic compounds with a single analysis. To our knowledge, this approach is among the few studies in which two FT-MS platforms combining LC and FIA methods were integrated to provide solutions to quality control aspects of OO. Moreover, both lipophilic and hydrophilic components are analyzed together, providing a holistic quality control workflow for OO.

Fast and sensitive flow-injection mass spectrometry metabolomics by analyzing sample-specific ion distributions.

Mass spectrometry based metabolomics is a widely used approach in biomedical research. However, current methods coupling mass spectrometry with chromatography are time-consuming and not suitable for high-throughput analysis of thousands of samples. An alternative approach is flow-injection mass spectrometry (FI-MS) in which samples are directly injected to the ionization source. Here, we show that the sensitivity of Orbitrap FI-MS metabolomics methods is limited by ion competition effect. We describe an approach for overcoming this effect by analyzing the distribution of ion m/z values and computationally determining a series of optimal scan ranges. This enables reproducible detection of ~9,000 and ~10,000 m/z features in metabolomics and lipidomics analysis of serum samples, respectively, with a sample scan time of ~15 s and duty time of ~30 s; a ~50% increase versus current spectral-stitching FI-MS. This approach facilitates high-throughput metabolomics for a variety of applications, including biomarker discovery and functional genomics screens.

Identification and Comparison of Tannins in Gall of Rhus chinensis Mill. and Gall of Quercus infectoria Oliv. by High-Performance Liquid Chromatography-Electrospray Mass Spectrometry.

Gall of Rhus chinensis Mill. (Chinese galls) and gall of Quercus infectoria Oliv. (Turkish galls) have similar applications and chemical compositions, and their extracts have been widely used for industrial production and for medicinal applications. In this study, high-performance liquid chromatography-electrospray mass spectrometry (HPLC-ESI-MS/MS) methods were established for profiling the components of Chinese galls and Turkish galls. Compounds representing 96.56 and 99.15% of the total peak area of Chinese galls and Turkish galls were identified. The results identified that the ellagic acid, galloyl-HHDP-glucose and pedunculagin act as the identifying markers for the comparison of Chinese galls and Turkish galls in HPLC-ESI-MS/MS. The peak area of tetragalloyl-glucoside, heptagalloyl-glucoside and pentagalloyl-glucoside can be used to distinguish these two phytomedicines. This work provides a reference for the study of the chemical composition of Chinese galls and Turkish galls, which not only introduce a simple and reliable method to prevent the adulteration or misuse of Chinese galls and Turkish galls but also lay the foundations for clarifying the material basis of their similar pharmacological action.