ABSTRACT
Simultaneous high-resolution full-scan and tandem mass spectrometry (MS/MS) analysis using time of flight mass spectrometry brings an answer for increasing demand of retrospective and non-targeted data analysis. Such analysis combined with spectral library searching is a promising tool for targeted and untargeted screening of small molecules. Despite considerable extension of the panel of compounds of tandem mass spectral libraries, the heterogeneity of spectral data poses a major challenge against the effective usage of spectral libraries. Performance evaluation of available LC-MS/MS libraries will significantly increase credibility in the search results. The present work was aimed to evaluate fluctuation of MS/MS pattern, in the peak intensities distribution together with mass accuracy measurements, and in consequence, performance compliant with ion ratio and mass error criteria as principles in identification processes for targeted and untargeted contaminants at trace levels. Matrix effect and ultra-trace levels of concentration (from 50 ng l(-1) to 1000 ng l(-1) were evaluated as potential source of inaccuracy in the performance of spectral matching. Matrix-matched samples and real samples were screened for proof of applicability. By manual review of data and application of ion ratio and ppm error criteria, false negatives were obtained; this number diminished when in-house library was used, while with on-line MS/MS databases 100% of positive samples were found. In our experience, intensity of peaks across spectra was highly correlated to the concentration effect and matrix complexity. In turn, analysis of spectra acquired at trace concentrations and in different matrices results in better performance in providing correct and reliable identification.
Subject(s)
Chromatography, Liquid/methods , Data Mining/methods , Small Molecule Libraries , Tandem Mass Spectrometry/methods , Databases, Factual , Drug Contamination , Food Contamination , Ions/analysis , Ions/chemistry , User-Computer InterfaceABSTRACT
RATIONALE: Polycyclic musks have become a concern due to their bioaccumulation potential and ecotoxicological effects. The HHCB transformation product (TP) (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta[γ]-2-benzopyran; HHCB-lactone) is the most stable intermediate generated and it is frequently detected in river waters. The aim of this work was the identification of relevant TPs generated from UV irradiation and ozone treatments. METHODS: Identification of HHCB TPs was carried out by liquid chromatography/hybrid quadrupole time-of-flight mass spectrometry (LC/ESI-QTOF-MS) and two-dimensional gas chromatography/electron impact time-of-flight mass spectrometry (GC×GC-EI-TOF-MS). With LC/ESI-QTOF-MS, TPs were characterized by means of mass accuracy in both full-scan and MS/MS modes through information-dependent acquisition (IDA) and direct injection on-column. With stir bar sorptive extraction (SBSE)-GC×GC-EI-TOF-MS, identification was based on the enhanced separation capacity and screening of unknowns through the acquisition of full-range mass spectra. RESULTS: The effectiveness of these complementary techniques allowed a detailed evaluation of the main TPs. Eighteen TPs were elucidated based on mass accuracy, in both full-scan and MS/MS modes using LC/ESI-QTOF-MS with mass errors below 5 ppm and 10 ppm (mostly), respectively. Most of the TPs had not been analytically identified in previous studies. Separation of the enantiomeric species (R) and (S) of HHCB-lactone, and the identification of other relevant TPs, was performed using SBSE-GC×GC-EI-TOF-MS. CONCLUSIONS: LC/ESI-QTOF-MS and GC×GC-EI-TOF-MS analysis provides the best alternative for TP identification of chemicals of concern, which have a wide range of polarities and isobaric compounds. A prediction of PBT (persistence, bioaccumulation and toxicity) using the PBT Profiler program suggested a classification of 'very persistent' and 'very toxic' for most of the TPs identified.
Subject(s)
Benzopyrans/chemistry , Chromatography, Liquid/methods , Tandem Mass Spectrometry/methods , Gas Chromatography-Mass Spectrometry/methods , Kinetics , Oxidation-Reduction , Ozone/chemistry , Ultraviolet Rays , Water Pollutants, Chemical/chemistryABSTRACT
El presente estudio intenta analizar las características demográficas y clínicas (edad, sexo, estado civil, edad de inicio, número y características de ingresos previos, derivación, nivel cultural, antecedentes familiares), de los pacientes diagnosticados de trastorno de personalidad según la DSM-IV que asisten al Servicio de Urgencias del Hospital de Jaén durante el año 2003. Pretendemos determinar si existen diferencias entre los distintos tipos de trastorno de personalidad y los motivos de demanda de asistencia, como son intentos autolíticos, cuadros de ansiedad, depresión, pánico, episodios psicóticos, consumo de tóxicos, trastornos de conducta, etc. De igual modo se comparan las características de los ingresos de estos pacientes con los de la población total de enfermos atendidos en la Unidad de Agudos de Psiquiatría del Hospital de Jaén (AU)
