Search results for " mass spectrometry"
showing 10 items of 695 documents
First experimental proof of asymmetric charge transfer in ICP-MS/MS (ICP-QQQ-MS) through isotopically enriched oxygen as cell gas
2014
The quantification of a variety of elements in the field of ICP-MS is restricted by isobaric interferences. The recent development of ICP-MS/MS (“triple quadrupole” configuration) offers a new way to solve the problem of the detection of such elements affected by interferences because the signal caused by either the analyte or the isobaric interference can be shifted to another m/z through reactions with the cell gas (oxygen, ammonia or hydrogen). This system consists of two quadrupoles (Q1 and Q2) with a collision/reaction cell in between. When using the MS/MS mode of this configuration it becomes possible to restrict the ions entering the cell to a defined m/z and therefore get a better i…
Stir bar sorptive-dispersive microextraction mediated by magnetic nanoparticles-metal organic framework composite: Determination of N-nitrosamines in…
2019
Abstract A new analytical method based on the recently proposed stir bar sorptive-dispersive microextraction (SBSDME) technique has been developed to determine eight hazardous N-nitrosamines in cosmetic products. As previous step, a simple clean-up is carried out with hexane to remove those highly lipophilic compounds that disturb the SBSDME step. Subsequently, SBSDME is performed by using magnetic nanoparticles–metal organic framework composite, CoFe2O4/MIL-101(Fe), as sorbent to entrap the target analytes, which are later chemically desorbed and measured by liquid chromatography–tandem mass spectrometry (LC–MS/MS). The experimental variables related to the SBSDME procedure were studied to…
Target analysis and retrospective screening of mycotoxins and pharmacologically active substances in milk using an ultra-high-performance liquid chro…
2020
Milk is a nutritious food suitable for infants and adults, and it plays an important role in the human diet. However, it may also be a vehicle for food contaminants. In this report, we developed a method using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-Q-Exactive Orbitrap HRMS; Thermo Fisher Scientific, Waltham, MA) for simultaneous identification of target pharmacologically active substances and mycotoxins in milk. We also used the Q-Orbitrap operating in full scan mode to identify other possible drugs and microbial metabolites that occurred in samples. Fifty-six commercially available milk samples from the Italian market were analyze…
Assessment of oxidative damage to proteins and DNA in urine of newborn infants by a validated UPLC-MS/MS approach
2014
The assessment of oxidative stress is highly relevant in clinical Perinatology as it is associated to adverse outcomes in newborn infants. This study summarizes results from the validation of an Ultra Performance Liquid Chromatography-tandem Mass Spectrometry (UPLC-MS/MS) method for the simultaneous quantification of the urinary concentrations of a set of endogenous biomarkers, capable to provide a valid snapshot of the oxidative stress status applicable in human clinical trials, especially in the field of Perinatology. The set of analytes included are phenylalanine (Phe), para-tyrosine (p-Tyr), ortho-tyrosine (o-Tyr), meta-tyrosine (m-Tyr), 3-NO2-tyrosine (3NO(2)-Tyr), 3-Cl-tyrosine (3Cl-T…
Rapid assay of resveratrol in red wine by paper spray tandem mass spectrometry and isotope dilution.
2017
A rapid analytical approach for the assay of resveratrol in red wines, based on Paper Spray Mass Spectrometry (PS-MS) and Multiple Reaction Monitoring (MRM) is described. The assay involves the use of the stable isotope dilution method. The analytical parameters calculated analyzing fortified samples confirm the reliability of the proposed approach, with accuracy values about 100%, and LOD and LOQ values calculated at 0.5 and 0.8 μg/mL, respectively. Furthermore, both the recovery, which was quantitative for the analyte, and the reproducibility (RSD%), checked on different days on the same wine, always below 7%, highlighted the consistency of the methodology.
Optimization of instrumental parameters for improving sensitivity of single particle inductively-coupled plasma mass spectrometry analysis of gold
2021
Single particle inductively-coupled plasma mass spectrometry (spICP-MS) is a promising technique for analysis of engineered nanoparticles, whose utilization has increased substantially over the past years. Optimization of instrumental conditions is, however, crucial to improve the sensitivity and precision of nanoparticle (NP) detection. In this study, the influence of ICP-MS instrumental parameters (nebulizer gas flow, plasma radiofrequency-power and sampling depth) on the signal intensity of gold in spICP-MS was evaluated using dispersions of Au NPs and a solution of dissolved gold. The interaction effects of the main factors were found to have a significant effect on the signal intensity…
Ultra high performance liquid chromatography-time-of-flight high resolution mass spectrometry in the analysis of hexabromocyclododecane diastereomers…
2014
An efficient ultra high performance liquid chromatography (UHPLC)-time-of-flight high resolution mass spectrometry (TOF-HRMS) method was elaborated for the determination of hexabromocyclododecane (HBCD) diastereomers in fish samples and compared against UHPLC-Orbitrap-HRMS and UHPLC-triple quadrupole (QqQ) tandem MS (MS/MS) techniques. The TOF-HRMS analyzer was operated at high resolution (>10000 full width at half maximum (FWHM)) with scanning the m/z range from 600 to 700, to achieve picogram quantitation limits. The effects of various operational parameters on the instrumental response were systematically investigated. Evaluation of the influence of sample clean-up procedure steps on sig…
Investigation on sol–gel synthesized Ag-doped TiO2 cermet thin films
2005
Abstract Undoped TiO 2 and Ag–TiO 2 (up to 23 at.% Ag) cermet thin films and polycrystalline powders have been prepared by sol–gel process. Their structure, composition, surface morphology and optical properties have been investigated by X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and ultraviolet–visible spectroscopy (UV–VIS spectroscopy). It has been observed that while Ag does not form a solid solution with TiO 2 , it promotes the anatase to rutile phase transformation. The transformation temperature decreases from 827 °C for undoped TiO 2 to about 650 °C fo…
Mycotoxin contamination in laboratory rat feeds and their implications in animal research
2016
Compound feed is particularly vulnerable to multi-mycotoxin contamination. A method for the determination of 12 mycotoxins; enniatins A, A1, B, B1; aflatoxins B1, B2, G1, G2; OTA; ZEA; T-2 and HT-2 by liquid chromatography-tandem mass spectrometry has been developed and applied for the analysis of laboratory rat commercial feeds. The method trueness was checked by recovery assays at three different spiked levels (n = 9). Recoveries ranged from 73% to 112%, and the intra-day and inter-day precision were lower than 9% and 13%, respectively. Limits of quantitation were lower than 15 μg/kg. Twenty-seven laboratory rats feed samples showed multi-contamination by at least three up to six differen…
Development and validation of a liquid chromatography tandem mass spectrometry method for the analysis of beta-agonists in animal feed and drinking w…
2010
A reproducible, sensitive and selective multiresidue analytical method for seven beta-agonists: clenbuterol (CBT), clenpenterol (CPT), ractopamine (RTP), brombuterol (BBT), mabuterol (MBT), mapenterol (MPT), and hydroxymethylclenbuterol (HMCBT) was developed and validated by using liquid chromatography tandem mass spectrometry (LC-MS/MS) in feed and drinking water samples. The validation was achieved according to the criteria laid down in the Commission Decision 2002/657/EC, however it was necessary to use minimum required performance limits (MRPLs) proposed by the Community Reference Laboratories (CRLs) due to the lack of maximum residue limits (MRLs) for beta-agonists. By setting up these…