•A multiresidue analysis method for 219 pesticides in cereals was proposed.•Different buffer systems (EN and AOAC method) for sample extraction were compared.•For majority of the test pesticides, the ...LOQ was 5μgkg−1.•The r2 was >0.99 within the calibration linearity range of 2–200μgkg−1.•The matrix effects were evaluated and compared between the three matrices.
A simple and high-throughput multiresidue pesticide analysis method was developed and validated for 219 pesticides in cereals (corn, wheat flour and rice) based on QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure combined with gas chromatography–triple quadrupole mass spectrometry (GC–MS/MS). Different buffer system (acetate- and citrate-buffered) and sample to solvent ratios (sample amount) were compared in the modified QuEChERS procedure to get better recovery and clean-up results. The limits of quantification (LOQ) ranged between 5 and 50μgkg−1, and for the majority of the pesticides the LOQ were 5μgkg−1, which were below the regulatory maximum residue limits. The coefficient of determination (r2) was >0.99 within the calibration linearity range of 2–200μgkg−1 for the majority of the pesticides. Most recoveries at 5, 10, 20, 50, 100 and 200μgkg−1 were in the range 70–120% (n=6) with associated RSDs<20% indicating satisfactory accuracy.
A large screening of around 1,000 emerging contaminants, focused on licit and illicit drugs and their metabolites, has been made in urban wastewaters (both influent and effluent) and surface waters ...from the area of Bogotá, Colombia. After a simple generic solid-phase extraction (SPE) step with Oasis hydrophilic-lipophilic balanced (HLB) cartridges, analyses were made by ultra high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS) under MSᴱ mode (sequential acquisition of mass spectra at low energy (LE) and high collision energy (HE)). Accurate mass measurements and the information provided by MSᴱ on the presence of the (de)protonated molecule and fragment ions allowed the reliable identification of the compounds detected, even without reference standards being available in some cases (tentative identification). The compounds most frequently found were acetaminophen/paracetamol, carbamazepine and its dihydro-dihydroxylated metabolite, clarithromycin, diclofenac, ibuprofen, gemfibrozil, lincomycin, losartan, valsartan, the two metabolites of metamizole (4-acetamido-antipyrine and 4-formylamino-antipyrine), sucralose, and cocaine and its main metabolite benzoylecgonine. Caffeine, the sweetener saccharin, and two hydroxylated metabolites of losartan were tentatively identified in almost all samples analyzed. Pharmaceutical lidocaine was tentatively identified and subsequently confirmed with reference standard. For the first time, a general overview of the occurrence of drugs and their metabolites in the aquatic environment of Colombia has been reported. In the near future, target methodologies, typically based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), will need to be set up for accurate and sensitive quantification of the contaminants selected on the basis on the information provided in the present paper.
Liquid chromatography tandem mass spectrometry (LC-MS/MS) assays are considered the reference standard for serum steroid hormone analyses, while full urinary steroid profiles are only achievable by ...gas chromatography (GC–MS). Both LC-MS/MS and GC–MS have well documented strengths and limitations. Recently, commercial ultra-high performance supercritical fluid chromatography–tandem mass spectrometry (UHPSFC-MS/MS) systems have been developed. These systems combine the resolution of GC with the high-throughput capabilities of UHPLC. Uptake of this new technology into research and clinical labs has been slow, possibly due to the perceived increase in complexity. Here we therefore present fundamental principles of UHPSFC-MS/MS and the likely applications for this technology in the clinical research setting, while commenting on potential hurdles based on our experience to date.
Tumor tissue processing methodologies in combination with data‐independent acquisition mass spectrometry (DIA‐MS) have emerged that can comprehensively analyze the proteome of multiple tumor samples ...accurately and reproducibly. Increasing recognition and adoption of these technologies has resulted in a tranche of studies providing novel insights into cancer classification systems, functional tumor biology, cancer biomarkers, treatment response and drug targets. Despite this, with some limited exceptions, MS‐based proteomics has not yet been implemented in routine cancer clinical practice. Here, we summarize the use of DIA‐MS in studies that may pave the way for future clinical cancer applications, and highlight the role of alternative MS technologies and multi‐omic strategies. We discuss limitations and challenges of studies in this field to date and propose steps for integrating proteomic data into the cancer clinic.
Breath analysis research is being successfully pursued using a variety of analytical methods, prominent amongst which are gas chromatography with mass spectrometry, GC-MS, ion mobility spectrometry, ...IMS, and the fast flow and flow-drift tube techniques called selected ion flow tube mass spectrometry, SIFT-MS, and proton transfer reaction mass spectrometry, PTR-MS. In this paper the case is made for real-time breath analysis by obviating sample collection into bags or onto traps that can suffer from partial degradation of breath metabolites or the introduction of impurities. Real-time analysis of a broad range of volatile chemical compounds can be best achieved using SIFT-MS and PTR-MS, which are sufficiently sensitive and rapid to allow the simultaneous analyses of several trace gas metabolites in single breath exhalations. The basic principles and the ion chemistry that underpin these two analytical techniques are briefly described and the differences between them, including their respective strengths and weaknesses, are revealed, especially with reference to the analysis of the complex matrix that is exhaled breath. A recent innovation is described that combines time-of-flight mass spectrometry with the proton transfer flow-drift tube reactor, PTR-TOFMS, which provides greater resolution in the analytical mass spectrometer and allows separation of protonated isobaric molecules. Examples are presented of some recent data that well illustrate the quality and real-time feature of SIFT-MS and PTR-MS for the analysis of exhaled breath for physiological/biochemical/pharmacokinetics studies and for the identification and quantification of biomarkers relating to specific disease states.
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•Confirmatory method for five nitrofuran metabolites including the nifursol metabolite.•European Union Decision 2002/657/EC was used for the method validation.•The new RPA adopted by ...the EU has been fully achieved through CCα below 0.1 µg.kg−1.•Sample preparation allows to detect only protein-bound residues from matrices.•The method applies to the categories of meat and aquaculture products.
LC-MS/MS method for confirmation of nitrofuran metabolites in meat and aquaculture products, including the nifursol metabolite (DNSH), was developed. The nitrofuran metabolites investigated were as follows: 3-amino-2-oxazolidinone (AOZ), 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), 1-aminohydantoine (AHD), semicarbazide (SEM) and 3,5-dinitrosalicylic acid hydrazide (DNSH). The sample preparation includes a washing step, allowing to analyze only the fraction of protein-bound residues. The final optimized recovery solvent for injection was found to be a mixture of ammonium acetate 2 mM/acetonitrile (60/40 ; v/v). Matrix effects and stability in biological matrix and standard solution for DNSH have been also carried out. Method performances were assessed using criteria of the Decision (EC) No 2002/657 and considering the proposed-for-adoption reference point for action (RPA) of 0.50 µg.kg−1 under Reg 1871/2019. Trueness ranged 86.5%–103.7% and precision ranged 2.0%–6.5% on intra-laboratory reproducibility conditions. Decision limit (CCα) ranged 0.028–0.182 μg.kg−1 and capability of detection limit (CCβ) ranged 0.032–0.233 µg.kg−1.
Quality control in mass spectrometry‐based proteomics Bittremieux, Wout; Tabb, David L.; Impens, Francis ...
Mass spectrometry reviews,
September/October 2018, 2018-09-00, 20180901, Letnik:
37, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Mass spectrometry is a highly complex analytical technique and mass spectrometry‐based proteomics experiments can be subject to a large variability, which forms an obstacle to obtaining accurate and ...reproducible results. Therefore, a comprehensive and systematic approach to quality control is an essential requirement to inspire confidence in the generated results. A typical mass spectrometry experiment consists of multiple different phases including the sample preparation, liquid chromatography, mass spectrometry, and bioinformatics stages. We review potential sources of variability that can impact the results of a mass spectrometry experiment occurring in all of these steps, and we discuss how to monitor and remedy the negative influences on the experimental results. Furthermore, we describe how specialized quality control samples of varying sample complexity can be incorporated into the experimental workflow and how they can be used to rigorously assess detailed aspects of the instrument performance.
Ambient ionization mass spectrometry was developed as a sample preparation-free alternative to traditional MS-based workflows. Desorption electrospray ionization (DESI)-MS methods were demonstrated ...to allow the direct analysis of a broad range of samples including unaltered biological tissue specimens. In contrast to this advantageous feature, nowadays DESI-MS is almost exclusively used for sample preparation intensive mass spectrometric imaging (MSI) in the area of cancer research. As an alternative to MALDI, DESI-MSI offers matrix deposition-free experiment with improved signal in the lower (<500m/z) range. DESI-MSI enables the spatial mapping of tumor metabolism and has been broadly demonstrated to offer an alternative to frozen section histology for intraoperative tissue identification and surgical margin assessment. Rapid evaporative ionization mass spectrometry (REIMS) was developed exclusively for the latter purpose by the direct combination of electrosurgical devices and mass spectrometry. In case of the REIMS technology, aerosol particles produced by electrosurgical dissection are subjected to MS analysis, providing spectral information on the structural lipid composition of tissues. REIMS technology was demonstrated to give real-time information on the histological nature of tissues being dissected, deeming it an ideal tool for intraoperative tissue identification including surgical margin control. More recently, the method has also been used for the rapid lipidomic phenotyping of cancer cell lines as it was demonstrated in case of the NCI-60 cell line collection.
Background: Metabolomics is an emerging field with the potential to advance nutritional epidemiology; however, it has not yet been applied to large cohort studies.Objectives: Our first aim was to ...identify metabolites that are biomarkers of usual dietary intake. Second, among serum metabolites correlated with diet, we evaluated metabolite reproducibility and required sample sizes to determine the potential for metabolomics in epidemiologic studies.Design: Baseline serum from 502 participants in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial was analyzed by using ultra-high-performance liquid-phase chromatography with tandem mass spectrometry and gas chromatography–mass spectrometry. Usual intakes of 36 dietary groups were estimated by using a food-frequency questionnaire. Dietary biomarkers were identified by using partial Pearson's correlations with Bonferroni correction for multiple comparisons. Intraclass correlation coefficients (ICCs) between samples collected 1 y apart in a subset of 30 individuals were calculated to evaluate intraindividual metabolite variability.Results: We detected 412 known metabolites. Citrus, green vegetables, red meat, shellfish, fish, peanuts, rice, butter, coffee, beer, liquor, total alcohol, and multivitamins were each correlated with at least one metabolite (P < 1.093 × 10−6; r = −0.312 to 0.398); in total, 39 dietary biomarkers were identified. Some correlations (citrus intake with stachydrine) replicated previous studies; others, such as peanuts and tryptophan betaine, were novel findings. Other strong associations included coffee (with trigonelline-N-methylnicotinate and quinate) and alcohol (with ethyl glucuronide). Intraindividual variability in metabolite levels (1-y ICCs) ranged from 0.27 to 0.89. Large, but attainable, sample sizes are required to detect associations between metabolites and disease in epidemiologic studies, further emphasizing the usefulness of metabolomics in nutritional epidemiology.Conclusions: We identified dietary biomarkers by using metabolomics in an epidemiologic data set. Given the strength of the associations observed, we expect that some of these metabolites will be validated in future studies and later used as biomarkers in large cohorts to study diet-disease associations. The PLCO trial was registered at clinicaltrials.gov as NCT00002540.
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