Elena Pitarch | Universitat Jaume I de Castelló (original) (raw)

Papers by Elena Pitarch

Research paper thumbnail of Analytical key issues and challenges in the LC-MS/MS determination of antibiotics in wastewater

Analytica Chimica Acta, 2023

Research paper thumbnail of Determination of organochlorine compounds in human adipose tissue using automated liquid chromatographic clean up and gas chromatography—tandem mass spectrometry

Chromatographia, Jun 1, 2002

A multiresidue method based on automated normal-phase LC clean-up and GC-MS-MS analysis has been ... more A multiresidue method based on automated normal-phase LC clean-up and GC-MS-MS analysis has been developed for the determination of organochlorine pesticides and polychlorinated biphenyls in human adipose tissues. Analytes were extracted by dissolving the fat samples in n-hexane, and the hexane extracts were injected onto a silica gel column for automated LC clean-up prior to analysis by GC-MS-MS. The high efficiency of the HPLC clean up for the elimination of fats in combination and the use of GC with tandem mass spectrometry detection gave detection limits at the low ng g 1 concentration level for all analytes using as little as 0.25 g of sample. The overall analytical procedure was applied to several human abdominal fat tissue samples: HCB, 13-HCH, p,p'-DDE and the higher chlorinated PCBs (138, 153 and 180) were the most frequently detected compounds, at levels of 26-1273 ng g 1, 19-933 ng g 1,121-3945 ng g 1 and 56-496 ng g 1, respectively.

Research paper thumbnail of The relevant role of ion mobility separation in LC-HRMS based screening strategies for contaminants of emerging concern in the aquatic environment

Chemosphere, Oct 1, 2021

Ion mobility separation (IMS) coupled to high resolution mass spectrometry (IMS-HRMS) is a promis... more Ion mobility separation (IMS) coupled to high resolution mass spectrometry (IMS-HRMS) is a promising technique for (non-)target/suspect analysis of micropollutants in complex matrices. IMS separates ionized compounds based on their charge, shape and size facilitating the removal of co-eluting isomeric/isobaric species. Additionally, IMS data can be translated into collision cross-section (CCS) values, which can be used to increase the identification reliability. However, IMS-HRMS for the screening of contaminants of emerging concern (CECs) have been scarcely explored. In this study, the role of IMS-HRMS for the identification of CECs in complex matrices is highlighted, with emphasis on when and with which purpose is of use. The utilization of IMS can result in much cleaner mass spectra, which considerably facilitates data interpretation and the obtaining of reliable identifications. Furthermore, the robustness of IMS measurements across matrices permits the use of CCS as an additional relevant parameter during the identification step even when reference standards are not available. Moreover, an effect on the number of true and false identifications could be demonstrated by including IMS restrictions within the identification workflow. Data shown in this work is of special interest for environmental researchers dealing with the detection of CECs with state-of-the-art IMS-HRMS instruments.

Research paper thumbnail of Determination of the herbicide 4-chloro-2-methylphenoxyacetic acid and its main metabolite, 4-chloro-2-methylphenol in water and soil by liquid chromatography–electrospray tandem mass spectrometry

Journal of Chromatography A, Jul 1, 2001

A rapid and sensitive LC-electrospray tandem mass spectrometry method has been developed for the ... more A rapid and sensitive LC-electrospray tandem mass spectrometry method has been developed for the quantitation of 4-chloro-2-methylphenoxyacetic acid (MCPA) and 4-chloro-2-methylphenol in both water and soil samples. Soil samples were extracted in alkaline media and cleaned-up by solid-phase extraction with C18 cartridges before LC-MS analysis. The selectivity and sensitivity offered by the triple quadrupole allowed the direct injection of the water samples rendering a sample throughput of around 100 samples per day, without any sample pretreatment, rendering for MCPA a limit of detection of 40 ng/l. In order to increase the method sensitivity, mainly for metabolite, a previous solid-phase extraction step was also performed. The method was validated by means of recovery experiments using fortified water and soil samples, obtaining satisfactory recoveries for both compounds in water and for MCPA in soil. The validated procedures can be used for the specific monitoring of residues of MCPA and its main metabolite in environmental samples, as ground and surface waters and soils, providing more selectivity and sensitivity than the current UV-based methodology. Besides, sample manipulation is greatly reduced in comparison to other GC-MS based methods which require a previous derivatization.

Research paper thumbnail of The role of GC-MS/MS with triple quadrupole in pesticide residue analysis in food and the environment

Analytical Methods, 2013

Gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) using a triple quadrupole (QqQ)... more Gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) using a triple quadrupole (QqQ) analyzer has in the last few years become a powerful technique for the determination of pesticide residues due to its robustness, and excellent sensitivity and selectivity. This review gives an overview of currently published applications of GC-MS/MS with a QqQ analyzer for pesticide residue analysis of different food and environmental sample matrices. This technique allows the reliable quantification and identification of low pesticide concentrations for non-polar (semi) volatile compounds belonging to different chemical families. It has allowed a notable improvement of methods performance in comparison with the traditional GC methods with single stage quadrupole MS.

Research paper thumbnail of Quality classification of Spanish olive oils by untargeted gas chromatography coupled to hybrid quadrupole-time of flight mass spectrometry with atmospheric pressure chemical ionization and metabolomics-based statistical approach

Food Chemistry, Feb 1, 2017

The novel atmospheric pressure chemical ionization (APCI) source has been used in combination wit... more The novel atmospheric pressure chemical ionization (APCI) source has been used in combination with gas chromatography (GC) coupled to hybrid quadrupole time-of-flight (QTOF) mass spectrometry (MS) for determination of volatile components of olive oil, enhancing its potential for classification of olive oil samples according to their quality using a metabolomics-based approach. The full-spectrum acquisition has allowed the detection of volatile organic compounds (VOCs) in olive oil samples, including extra virgin, virgin and lampante qualities. A dynamic headspace extraction with cartridge Con formato: Español (alfab. internacional) Código de campo cambiado Con formato: Español (alfab. internacional) Con formato: Español (alfab. internacional) Con formato: Español (alfab. internacional) Con formato: Español (alfab. internacional) Con formato: Español (alfab.

Research paper thumbnail of Evaluation of direct sample injection as a fast, no-sample handling, approach for the LC-MS/MS monitoring of pharmaceuticals in different water matrices

Research paper thumbnail of Rapid and sensitive analytical method for the determination of amoxicillin and related compounds in water meeting the requirements of the European union watch list

Journal of Chromatography A, 2021

The presence of antibiotics in the aquatic environment is becoming one of the main research focus... more The presence of antibiotics in the aquatic environment is becoming one of the main research focus of scientists and policy makers. Proof of that is the inclusion of four antibiotics, amongst which is amoxicillin, in the EU Watch List (WL) (Decision 2020/1161/EU)) of substances for water monitoring. The accurate quantification of amoxicillin in water at the sub-ppb levels required by the WL is troublesome due to its physicochemical properties. In this work, the analytical challenges related to the determination of amoxicillin, and six related penicillins (ampicillin, cloxacillin, dicloxacillin, penicillin G, penicillin V and oxacillin), have been carefully addressed, including sample treatment, sample stability, chromatographic analysis and mass spectrometric detection by triple quadrupole. Given the low recoveries obtained using different solid-phase extraction cartridges, we applied the direct injection of water samples using a reversed-phase chromatographic column that allowed working with 100% aqueous mobile phase. Matrix effects were evaluated and corrected using the isotopically labelled internal standard or correction factors based on signal suppression observed in the analysis of spiked samples. The methodology developed was satisfactorily validated at 50 and 500 ng L - 1 for the seven penicillins studied, and it was applied to different types of water matrices, revealing the presence of ampicillin in one surface water sample and cloxacillin in three effluent wastewater samples.

Research paper thumbnail of The relevant role of ion mobility separation in LC-HRMS based screening strategies for contaminants of emerging concern in the aquatic environment

Chemosphere, 2021

Ion mobility separation (IMS) coupled to high resolution mass spectrometry (IMS-HRMS) is a promis... more Ion mobility separation (IMS) coupled to high resolution mass spectrometry (IMS-HRMS) is a promising technique for (non-)target/suspect analysis of micropollutants in complex matrices. IMS separates ionized compounds based on their charge, shape and size facilitating the removal of co-eluting isomeric/isobaric species. Additionally, IMS data can be translated into collision cross-section (CCS) values, which can be used to increase the identification reliability. However, IMS-HRMS for the screening of contaminants of emerging concern (CECs) have been scarcely explored. In this study, the role of IMS-HRMS for the identification of CECs in complex matrices is highlighted, with emphasis on when and with which purpose is of use. The utilization of IMS can result in much cleaner mass spectra, which considerably facilitates data interpretation and the obtaining of reliable identifications. Furthermore, the robustness of IMS measurements across matrices permits the use of CCS as an additional relevant parameter during the identification step even when reference standards are not available. Moreover, an effect on the number of true and false identifications could be demonstrated by including IMS restrictions within the identification workflow. Data shown in this work is of special interest for environmental researchers dealing with the detection of CECs with state-of-the-art IMS-HRMS instruments.

Research paper thumbnail of The embodiment of wastewater data for the estimation of illicit drug consumption in Spain

Science of The Total Environment, 2021

Highlights-First national wastewater campaign to estimate illicit drug consumption in Spain-Metha... more Highlights-First national wastewater campaign to estimate illicit drug consumption in Spain-Methamphetamine and MDMA positively correlated to population size-NPS were only detected sporadically at low concentrations in wastewater-Agreement between WBE consumption estimates and other indicators for several drugs-Size of the retail drug market and contribution to gross domestic product estimated / 51

Research paper thumbnail of Rapid multiresidue determination of organochlorine and organophosphorus compounds in human serum by solid-phase extraction and gas chromatography coupled to tandem mass spectrometry

Analytical and Bioanalytical Chemistry, 2003

A rapid analytical method for the multiresidue determination of several organochlorine and organo... more A rapid analytical method for the multiresidue determination of several organochlorine and organophosphorus pesticides and polychlorinated biphenyls in human serum samples has been developed. Analytes were isolated by solid-phase extraction using C18 cartridges with subsequent analysis by GC-MS/MS using a glass liner packed with CarboFrit in the GC injection port. Labelled surrogate internal standards (fenitrothion D6, HCB (13)C6, p, p'-DDE D8 and PCB 138 (13)C12) were added to the samples before the extraction and were used for quantitation and for quality control in the analysis of real-world samples. Accuracy and precision were evaluated by using serum samples fortified at two concentration levels for the three families of compounds, with satisfactory results in the majority of cases. The high selectivity and sensitivity of GC-MS/MS allowed low detection limits of 0.05-0.5 ng mL(-1) for most of the analytes investigated. The developed procedure improves other current methodologies for the analysis of pesticides and PCBs in biological fluids, especially as regards to analysis time and simplicity of sample treatment. The method was applied to several serum samples obtained from farmers devoted to citrus crop production. Chlorpyrifos, HCB, p, p'-DDE and the higher chlorinated PCBs (153, 138 and 180) were the most frequently detected compounds.

Research paper thumbnail of Quality classification of Spanish olive oils by untargeted gas chromatography coupled to hybrid quadrupole-time of flight mass spectrometry with atmospheric pressure chemical ionization and metabolomics-based statistical approach

Food chemistry, 2017

The novel atmospheric pressure chemical ionization (APCI) source has been used in combination wit... more The novel atmospheric pressure chemical ionization (APCI) source has been used in combination with gas chromatography (GC) coupled to hybrid quadrupole time-of-flight (QTOF) mass spectrometry (MS) for determination of volatile components of olive oil, enhancing its potential for classification of olive oil samples according to their quality using a metabolomics-based approach. The full-spectrum acquisition has allowed the detection of volatile organic compounds (VOCs) in olive oil samples, including Extra Virgin, Virgin and Lampante qualities. A dynamic headspace extraction with cartridge solvent elution was applied. The metabolomics strategy consisted of three different steps: a full mass spectral alignment of GC-MS data using MzMine 2.0, a multivariate analysis using Ez-Info and the creation of the statistical model with combinations of responses for molecular fragments. The model was finally validated using blind samples, obtaining an accuracy in oil classification of 70%, taking...

Research paper thumbnail of Assessment of the efficacy of Artemia sp (Crustacea) cysts chorion as barrier to chlorpyrifos (organophosphorus pesticide) exposure. Effect on hatching and survival

Science of The Total Environment, 2006

In order to reveal the efficacy of the Artemia cysts chorion as barrier to the organophosphorus p... more In order to reveal the efficacy of the Artemia cysts chorion as barrier to the organophosphorus pesticide chlorpyrifos, whole and decapsulated cysts have been exposed to 10 mg L(-1) chlorpyrifos in sea water during hydration and hatching phase, separately. The concentration of chlorpyrifos in capsulated and decapsulated cysts after exposure has been determined in order to elucidate the efficacy of chorion as protection to the embryo. The results obtained demonstrate the ability of the cysts chorion to obstruct the pass of chlorpyrifos molecules through this protection structure. Thus, the concentration of chlorpyrifos in exposed decapsulated cysts is higher than in exposed whole cysts. Moreover, after removing the chorion of exposed cysts, the concentration of chlorpyrifos in the embryo was lower than that of cysts exposed, what would demonstrate the retention of chlorpyrifos molecules by the shell. Hatching was not severely affected by exposure to the insecticide whereas survival at 44 h of the nauplii exposed to chlorpyrifos was significantly different from the controls. Survival of nauplii hatched from exposed decapsulated cysts was higher than that from those hatched from exposed whole cysts, probably because of the lower vitality of the latter, due to depletion of energy reserves during hatching.

Research paper thumbnail of Mass spectrometric behavior of anabolic androgenic steroids using gas chromatography coupled to atmospheric pressure chemical ionization source. Part I: Ionization

Journal of Mass Spectrometry, 2014

Research paper thumbnail of Potential of atmospheric pressure chemical ionization source in GC-QTOF MS for pesticide residue analysis

Journal of Mass Spectrometry, 2010

h i g h l i g h t s g r a p h i c a l a b s t r a c t APCI source has been evaluated for the scre... more h i g h l i g h t s g r a p h i c a l a b s t r a c t APCI source has been evaluated for the screening of 16 exogenous AAS in urine. Suitable precision was observed for APCI although lower than with EI. LODs for APCI were commonly lower. GC-APCI-MS/MS method increases the period in which the misuse of 4ClMTD is detected. APCI source is an adequate alternative to the traditional EI source in GC eMS.

Research paper thumbnail of Determination of the herbicide 4-chloro-2-methylphenoxyacetic acid and its main metabolite, 4-chloro-2-methylphenol in water and soil by liquid chromatography–electrospray tandem mass spectrometry

Journal of Chromatography A, 2001

A rapid and sensitive LC-electrospray tandem mass spectrometry method has been developed for the ... more A rapid and sensitive LC-electrospray tandem mass spectrometry method has been developed for the quantitation of 4-chloro-2-methylphenoxyacetic acid (MCPA) and 4-chloro-2-methylphenol in both water and soil samples. Soil samples were extracted in alkaline media and cleaned-up by solid-phase extraction with C18 cartridges before LC-MS analysis. The selectivity and sensitivity offered by the triple quadrupole allowed the direct injection of the water samples rendering a sample throughput of around 100 samples per day, without any sample pretreatment, rendering for MCPA a limit of detection of 40 ng/l. In order to increase the method sensitivity, mainly for metabolite, a previous solid-phase extraction step was also performed. The method was validated by means of recovery experiments using fortified water and soil samples, obtaining satisfactory recoveries for both compounds in water and for MCPA in soil. The validated procedures can be used for the specific monitoring of residues of MCPA and its main metabolite in environmental samples, as ground and surface waters and soils, providing more selectivity and sensitivity than the current UV-based methodology. Besides, sample manipulation is greatly reduced in comparison to other GC-MS based methods which require a previous derivatization.

Research paper thumbnail of Multiresidue liquid chromatography tandem mass spectrometry determination of 52 non gas chromatography-amenable pesticides and metabolites in different food commodities

Journal of Chromatography A, 2006

A multiresidue method is developed for the screening, quantification and confirmation of 43 pesti... more A multiresidue method is developed for the screening, quantification and confirmation of 43 pesticides, belonging to different chemical families of insecticides, acaricides, fungicides, herbicides and plant growth regulators, and 9 pesticide metabolites in four fruit and vegetable matrices. Pesticide residues are extracted from the samples with MeOH:H 2 O (80:20, v/v) 0.1% HCOOH, and then a cleanup step using OASIS HLB SPE cartridges is applied. The SPE eluate is concentrated and the final volume adjusted to 1 mL with MeOH:H 2 O (10:90, v/v) before injection into LC-MS/MS. Analyses are performed using electrospray ionization (ESI) and triple quadrupole (QqQ) analyzer. The method has been validated based on the SANCO European Guidelines for representative samples that were chosen to study the influence of different matrices: high water content (tomato), high acidic content (lemon), high sugar content (raisin) and high lipidic content (avocado). Special attention has been given to minimize the degradation of some pesticides into their metabolites and the losses observed in the evaporation step. Under the optimized conditions, the recoveries were, with a few exceptions, in the range 70-110% with satisfactory precision (CV ≤ 15%). The quantification of analytes was carried out using the most sensitive transition for every compound and by "matrix-matched" standards calibration. The method can be used for the accurate determination of 52 pesticides and metabolites in one single determination step at the 0.01 mg/kg level. Confirmation of residues detected in samples is performed by an independent injection into the LC-MS/MS system by acquiring additional MS/MS transitions to that used for quantification. The acquisition of the highest number of available transitions is suggested for unequivocal confirmation of the analyte.

Research paper thumbnail of Rapid direct determination of pesticides and metabolites in environmental water samples at sub-μg/l level by on-line solid-phase extraction-liquid chromatography–electrospray tandem mass spectrometry

Journal of Chromatography A, 2001

A very rapid, multi-residual, sensitive and specific procedure for determining 35 pesticides in e... more A very rapid, multi-residual, sensitive and specific procedure for determining 35 pesticides in environmental ground and surface water in proposed. It is based on the use of solid-phase extraction (SPE) combined on-line with liquid chromatography (LC) electrospray (ESI) tandem mass spectrometry (MS-MS). Simultaneous target analysis of 29 pesticides (1 fungicide, 16 insecticides, 10 herbicides and 2 acaricides) and 6 metabolites with positive or negative ionization was reached by the direct injection of only 1.3 ml of filtered water sample, with a total analysis time of 18 min. The SPE-LC-MS-MS method was validated, obtaining good results for all compounds at 0.5 and 0.1 microg/l. Most of them could be correctly quantified at a concentration level as low as 25 ng/l. Efficiency and applicability of this method was evaluated by the analysis of several samples included in a monitoring program.

Research paper thumbnail of Multiresidue Determination of Endosulfan and Metabolic Derivatives in Human Adipose Tissue Using Automated Liquid Chromatographic Cleanup and Gas Chromatographic Analysis

Journal of Analytical Toxicology, 2002

A multiresidue method based on normal-phase liquid chromatography (LC) cleanup and gas chromatogr... more A multiresidue method based on normal-phase liquid chromatography (LC) cleanup and gas chromatography-electron capture detection-mass selective detection (GC-ECD-MSD) analysis has been developed for the determination of endosulfan and its main metabolic derivatives in human adipose tissues. Analytes were extracted by dissolving the fat samples in n-hexane, and the hexanic extracts were directly injected onto the silicagel column of the automated LC cleanup system. Purified LC extracts were analyzed by GC-ECD or GC-MSD, without any solvent exchanges or preconcentration steps. The high efficiency of the high-performance liquid chromatographic cleanup for the elimination of fats allowed to reach detection limits for all analytes at low nanograms-per-gram concentration levels. The optimized overall analytical procedure was applied to 18 selected human mammary adipose and abdominal fat tissue samples, p,p~-DDE, hexachlor0benzene, and ~-HCH were the most frequently detected compounds, and residues of endosulfansulfate and-ether were also found in several samples. All findings were confirmed by an additional GC-MS-MS analysis of the LC sample extracts.

Research paper thumbnail of Biomagnification Study on Organochlorine Compounds in Marine Aquaculture:  The Sea Bass (Dicentrarchus labrax) as a Model

Environmental Science & Technology

Biomagnification of organochlorine compounds (pesticides and polychlorinated biphenyls) through t... more Biomagnification of organochlorine compounds (pesticides and polychlorinated biphenyls) through the marine aquaculture food chain is investigated. From first-feeding, specimens of sea bass were exposed to commercial fish feed (that contained DDTs and PCBs residues) for ca. 24 months, and selected tissues (white and red muscle, liver, and visceral fat) were analyzed after 6 and 24 months of diet exposure. Data obtained showed that experimental fish tissues presented a similar contamination pattern to that of fish feed, and biomagnification processes of these compounds were proved. Additionally, commercial sea bass cultured in farms from the western Mediterranean were analyzed, their organochlorine concentrations being significantly lower than those of the 24 month old experimental fish. Thus, the exposition of human population to OCs through consumption of cultured fish would be lower than expected from experimental biomagnification studies, although red muscle presented similar OC levels in both cases, which were much higher than those of white muscle. Although levels of organochlorine compounds were found to be low, the persistence, ubiquity, and toxicity of these compounds, together with their presence in fish feed, make it necessary to monitor OC residues in the routine quality assurance programs of aquaculture activities, as this food chain is a source of these toxic compounds for human consumers. The development of sensitive analytical methodology based on GC-MS/MS has allowed for the reaching of low detection limits required to carry out the present study.

Research paper thumbnail of Analytical key issues and challenges in the LC-MS/MS determination of antibiotics in wastewater

Analytica Chimica Acta, 2023

Research paper thumbnail of Determination of organochlorine compounds in human adipose tissue using automated liquid chromatographic clean up and gas chromatography—tandem mass spectrometry

Chromatographia, Jun 1, 2002

A multiresidue method based on automated normal-phase LC clean-up and GC-MS-MS analysis has been ... more A multiresidue method based on automated normal-phase LC clean-up and GC-MS-MS analysis has been developed for the determination of organochlorine pesticides and polychlorinated biphenyls in human adipose tissues. Analytes were extracted by dissolving the fat samples in n-hexane, and the hexane extracts were injected onto a silica gel column for automated LC clean-up prior to analysis by GC-MS-MS. The high efficiency of the HPLC clean up for the elimination of fats in combination and the use of GC with tandem mass spectrometry detection gave detection limits at the low ng g 1 concentration level for all analytes using as little as 0.25 g of sample. The overall analytical procedure was applied to several human abdominal fat tissue samples: HCB, 13-HCH, p,p'-DDE and the higher chlorinated PCBs (138, 153 and 180) were the most frequently detected compounds, at levels of 26-1273 ng g 1, 19-933 ng g 1,121-3945 ng g 1 and 56-496 ng g 1, respectively.

Research paper thumbnail of The relevant role of ion mobility separation in LC-HRMS based screening strategies for contaminants of emerging concern in the aquatic environment

Chemosphere, Oct 1, 2021

Ion mobility separation (IMS) coupled to high resolution mass spectrometry (IMS-HRMS) is a promis... more Ion mobility separation (IMS) coupled to high resolution mass spectrometry (IMS-HRMS) is a promising technique for (non-)target/suspect analysis of micropollutants in complex matrices. IMS separates ionized compounds based on their charge, shape and size facilitating the removal of co-eluting isomeric/isobaric species. Additionally, IMS data can be translated into collision cross-section (CCS) values, which can be used to increase the identification reliability. However, IMS-HRMS for the screening of contaminants of emerging concern (CECs) have been scarcely explored. In this study, the role of IMS-HRMS for the identification of CECs in complex matrices is highlighted, with emphasis on when and with which purpose is of use. The utilization of IMS can result in much cleaner mass spectra, which considerably facilitates data interpretation and the obtaining of reliable identifications. Furthermore, the robustness of IMS measurements across matrices permits the use of CCS as an additional relevant parameter during the identification step even when reference standards are not available. Moreover, an effect on the number of true and false identifications could be demonstrated by including IMS restrictions within the identification workflow. Data shown in this work is of special interest for environmental researchers dealing with the detection of CECs with state-of-the-art IMS-HRMS instruments.

Research paper thumbnail of Determination of the herbicide 4-chloro-2-methylphenoxyacetic acid and its main metabolite, 4-chloro-2-methylphenol in water and soil by liquid chromatography–electrospray tandem mass spectrometry

Journal of Chromatography A, Jul 1, 2001

A rapid and sensitive LC-electrospray tandem mass spectrometry method has been developed for the ... more A rapid and sensitive LC-electrospray tandem mass spectrometry method has been developed for the quantitation of 4-chloro-2-methylphenoxyacetic acid (MCPA) and 4-chloro-2-methylphenol in both water and soil samples. Soil samples were extracted in alkaline media and cleaned-up by solid-phase extraction with C18 cartridges before LC-MS analysis. The selectivity and sensitivity offered by the triple quadrupole allowed the direct injection of the water samples rendering a sample throughput of around 100 samples per day, without any sample pretreatment, rendering for MCPA a limit of detection of 40 ng/l. In order to increase the method sensitivity, mainly for metabolite, a previous solid-phase extraction step was also performed. The method was validated by means of recovery experiments using fortified water and soil samples, obtaining satisfactory recoveries for both compounds in water and for MCPA in soil. The validated procedures can be used for the specific monitoring of residues of MCPA and its main metabolite in environmental samples, as ground and surface waters and soils, providing more selectivity and sensitivity than the current UV-based methodology. Besides, sample manipulation is greatly reduced in comparison to other GC-MS based methods which require a previous derivatization.

Research paper thumbnail of The role of GC-MS/MS with triple quadrupole in pesticide residue analysis in food and the environment

Analytical Methods, 2013

Gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) using a triple quadrupole (QqQ)... more Gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) using a triple quadrupole (QqQ) analyzer has in the last few years become a powerful technique for the determination of pesticide residues due to its robustness, and excellent sensitivity and selectivity. This review gives an overview of currently published applications of GC-MS/MS with a QqQ analyzer for pesticide residue analysis of different food and environmental sample matrices. This technique allows the reliable quantification and identification of low pesticide concentrations for non-polar (semi) volatile compounds belonging to different chemical families. It has allowed a notable improvement of methods performance in comparison with the traditional GC methods with single stage quadrupole MS.

Research paper thumbnail of Quality classification of Spanish olive oils by untargeted gas chromatography coupled to hybrid quadrupole-time of flight mass spectrometry with atmospheric pressure chemical ionization and metabolomics-based statistical approach

Food Chemistry, Feb 1, 2017

The novel atmospheric pressure chemical ionization (APCI) source has been used in combination wit... more The novel atmospheric pressure chemical ionization (APCI) source has been used in combination with gas chromatography (GC) coupled to hybrid quadrupole time-of-flight (QTOF) mass spectrometry (MS) for determination of volatile components of olive oil, enhancing its potential for classification of olive oil samples according to their quality using a metabolomics-based approach. The full-spectrum acquisition has allowed the detection of volatile organic compounds (VOCs) in olive oil samples, including extra virgin, virgin and lampante qualities. A dynamic headspace extraction with cartridge Con formato: Español (alfab. internacional) Código de campo cambiado Con formato: Español (alfab. internacional) Con formato: Español (alfab. internacional) Con formato: Español (alfab. internacional) Con formato: Español (alfab. internacional) Con formato: Español (alfab.

Research paper thumbnail of Evaluation of direct sample injection as a fast, no-sample handling, approach for the LC-MS/MS monitoring of pharmaceuticals in different water matrices

Research paper thumbnail of Rapid and sensitive analytical method for the determination of amoxicillin and related compounds in water meeting the requirements of the European union watch list

Journal of Chromatography A, 2021

The presence of antibiotics in the aquatic environment is becoming one of the main research focus... more The presence of antibiotics in the aquatic environment is becoming one of the main research focus of scientists and policy makers. Proof of that is the inclusion of four antibiotics, amongst which is amoxicillin, in the EU Watch List (WL) (Decision 2020/1161/EU)) of substances for water monitoring. The accurate quantification of amoxicillin in water at the sub-ppb levels required by the WL is troublesome due to its physicochemical properties. In this work, the analytical challenges related to the determination of amoxicillin, and six related penicillins (ampicillin, cloxacillin, dicloxacillin, penicillin G, penicillin V and oxacillin), have been carefully addressed, including sample treatment, sample stability, chromatographic analysis and mass spectrometric detection by triple quadrupole. Given the low recoveries obtained using different solid-phase extraction cartridges, we applied the direct injection of water samples using a reversed-phase chromatographic column that allowed working with 100% aqueous mobile phase. Matrix effects were evaluated and corrected using the isotopically labelled internal standard or correction factors based on signal suppression observed in the analysis of spiked samples. The methodology developed was satisfactorily validated at 50 and 500 ng L - 1 for the seven penicillins studied, and it was applied to different types of water matrices, revealing the presence of ampicillin in one surface water sample and cloxacillin in three effluent wastewater samples.

Research paper thumbnail of The relevant role of ion mobility separation in LC-HRMS based screening strategies for contaminants of emerging concern in the aquatic environment

Chemosphere, 2021

Ion mobility separation (IMS) coupled to high resolution mass spectrometry (IMS-HRMS) is a promis... more Ion mobility separation (IMS) coupled to high resolution mass spectrometry (IMS-HRMS) is a promising technique for (non-)target/suspect analysis of micropollutants in complex matrices. IMS separates ionized compounds based on their charge, shape and size facilitating the removal of co-eluting isomeric/isobaric species. Additionally, IMS data can be translated into collision cross-section (CCS) values, which can be used to increase the identification reliability. However, IMS-HRMS for the screening of contaminants of emerging concern (CECs) have been scarcely explored. In this study, the role of IMS-HRMS for the identification of CECs in complex matrices is highlighted, with emphasis on when and with which purpose is of use. The utilization of IMS can result in much cleaner mass spectra, which considerably facilitates data interpretation and the obtaining of reliable identifications. Furthermore, the robustness of IMS measurements across matrices permits the use of CCS as an additional relevant parameter during the identification step even when reference standards are not available. Moreover, an effect on the number of true and false identifications could be demonstrated by including IMS restrictions within the identification workflow. Data shown in this work is of special interest for environmental researchers dealing with the detection of CECs with state-of-the-art IMS-HRMS instruments.

Research paper thumbnail of The embodiment of wastewater data for the estimation of illicit drug consumption in Spain

Science of The Total Environment, 2021

Highlights-First national wastewater campaign to estimate illicit drug consumption in Spain-Metha... more Highlights-First national wastewater campaign to estimate illicit drug consumption in Spain-Methamphetamine and MDMA positively correlated to population size-NPS were only detected sporadically at low concentrations in wastewater-Agreement between WBE consumption estimates and other indicators for several drugs-Size of the retail drug market and contribution to gross domestic product estimated / 51

Research paper thumbnail of Rapid multiresidue determination of organochlorine and organophosphorus compounds in human serum by solid-phase extraction and gas chromatography coupled to tandem mass spectrometry

Analytical and Bioanalytical Chemistry, 2003

A rapid analytical method for the multiresidue determination of several organochlorine and organo... more A rapid analytical method for the multiresidue determination of several organochlorine and organophosphorus pesticides and polychlorinated biphenyls in human serum samples has been developed. Analytes were isolated by solid-phase extraction using C18 cartridges with subsequent analysis by GC-MS/MS using a glass liner packed with CarboFrit in the GC injection port. Labelled surrogate internal standards (fenitrothion D6, HCB (13)C6, p, p'-DDE D8 and PCB 138 (13)C12) were added to the samples before the extraction and were used for quantitation and for quality control in the analysis of real-world samples. Accuracy and precision were evaluated by using serum samples fortified at two concentration levels for the three families of compounds, with satisfactory results in the majority of cases. The high selectivity and sensitivity of GC-MS/MS allowed low detection limits of 0.05-0.5 ng mL(-1) for most of the analytes investigated. The developed procedure improves other current methodologies for the analysis of pesticides and PCBs in biological fluids, especially as regards to analysis time and simplicity of sample treatment. The method was applied to several serum samples obtained from farmers devoted to citrus crop production. Chlorpyrifos, HCB, p, p'-DDE and the higher chlorinated PCBs (153, 138 and 180) were the most frequently detected compounds.

Research paper thumbnail of Quality classification of Spanish olive oils by untargeted gas chromatography coupled to hybrid quadrupole-time of flight mass spectrometry with atmospheric pressure chemical ionization and metabolomics-based statistical approach

Food chemistry, 2017

The novel atmospheric pressure chemical ionization (APCI) source has been used in combination wit... more The novel atmospheric pressure chemical ionization (APCI) source has been used in combination with gas chromatography (GC) coupled to hybrid quadrupole time-of-flight (QTOF) mass spectrometry (MS) for determination of volatile components of olive oil, enhancing its potential for classification of olive oil samples according to their quality using a metabolomics-based approach. The full-spectrum acquisition has allowed the detection of volatile organic compounds (VOCs) in olive oil samples, including Extra Virgin, Virgin and Lampante qualities. A dynamic headspace extraction with cartridge solvent elution was applied. The metabolomics strategy consisted of three different steps: a full mass spectral alignment of GC-MS data using MzMine 2.0, a multivariate analysis using Ez-Info and the creation of the statistical model with combinations of responses for molecular fragments. The model was finally validated using blind samples, obtaining an accuracy in oil classification of 70%, taking...

Research paper thumbnail of Assessment of the efficacy of Artemia sp (Crustacea) cysts chorion as barrier to chlorpyrifos (organophosphorus pesticide) exposure. Effect on hatching and survival

Science of The Total Environment, 2006

In order to reveal the efficacy of the Artemia cysts chorion as barrier to the organophosphorus p... more In order to reveal the efficacy of the Artemia cysts chorion as barrier to the organophosphorus pesticide chlorpyrifos, whole and decapsulated cysts have been exposed to 10 mg L(-1) chlorpyrifos in sea water during hydration and hatching phase, separately. The concentration of chlorpyrifos in capsulated and decapsulated cysts after exposure has been determined in order to elucidate the efficacy of chorion as protection to the embryo. The results obtained demonstrate the ability of the cysts chorion to obstruct the pass of chlorpyrifos molecules through this protection structure. Thus, the concentration of chlorpyrifos in exposed decapsulated cysts is higher than in exposed whole cysts. Moreover, after removing the chorion of exposed cysts, the concentration of chlorpyrifos in the embryo was lower than that of cysts exposed, what would demonstrate the retention of chlorpyrifos molecules by the shell. Hatching was not severely affected by exposure to the insecticide whereas survival at 44 h of the nauplii exposed to chlorpyrifos was significantly different from the controls. Survival of nauplii hatched from exposed decapsulated cysts was higher than that from those hatched from exposed whole cysts, probably because of the lower vitality of the latter, due to depletion of energy reserves during hatching.

Research paper thumbnail of Mass spectrometric behavior of anabolic androgenic steroids using gas chromatography coupled to atmospheric pressure chemical ionization source. Part I: Ionization

Journal of Mass Spectrometry, 2014

Research paper thumbnail of Potential of atmospheric pressure chemical ionization source in GC-QTOF MS for pesticide residue analysis

Journal of Mass Spectrometry, 2010

h i g h l i g h t s g r a p h i c a l a b s t r a c t APCI source has been evaluated for the scre... more h i g h l i g h t s g r a p h i c a l a b s t r a c t APCI source has been evaluated for the screening of 16 exogenous AAS in urine. Suitable precision was observed for APCI although lower than with EI. LODs for APCI were commonly lower. GC-APCI-MS/MS method increases the period in which the misuse of 4ClMTD is detected. APCI source is an adequate alternative to the traditional EI source in GC eMS.

Research paper thumbnail of Determination of the herbicide 4-chloro-2-methylphenoxyacetic acid and its main metabolite, 4-chloro-2-methylphenol in water and soil by liquid chromatography–electrospray tandem mass spectrometry

Journal of Chromatography A, 2001

A rapid and sensitive LC-electrospray tandem mass spectrometry method has been developed for the ... more A rapid and sensitive LC-electrospray tandem mass spectrometry method has been developed for the quantitation of 4-chloro-2-methylphenoxyacetic acid (MCPA) and 4-chloro-2-methylphenol in both water and soil samples. Soil samples were extracted in alkaline media and cleaned-up by solid-phase extraction with C18 cartridges before LC-MS analysis. The selectivity and sensitivity offered by the triple quadrupole allowed the direct injection of the water samples rendering a sample throughput of around 100 samples per day, without any sample pretreatment, rendering for MCPA a limit of detection of 40 ng/l. In order to increase the method sensitivity, mainly for metabolite, a previous solid-phase extraction step was also performed. The method was validated by means of recovery experiments using fortified water and soil samples, obtaining satisfactory recoveries for both compounds in water and for MCPA in soil. The validated procedures can be used for the specific monitoring of residues of MCPA and its main metabolite in environmental samples, as ground and surface waters and soils, providing more selectivity and sensitivity than the current UV-based methodology. Besides, sample manipulation is greatly reduced in comparison to other GC-MS based methods which require a previous derivatization.

Research paper thumbnail of Multiresidue liquid chromatography tandem mass spectrometry determination of 52 non gas chromatography-amenable pesticides and metabolites in different food commodities

Journal of Chromatography A, 2006

A multiresidue method is developed for the screening, quantification and confirmation of 43 pesti... more A multiresidue method is developed for the screening, quantification and confirmation of 43 pesticides, belonging to different chemical families of insecticides, acaricides, fungicides, herbicides and plant growth regulators, and 9 pesticide metabolites in four fruit and vegetable matrices. Pesticide residues are extracted from the samples with MeOH:H 2 O (80:20, v/v) 0.1% HCOOH, and then a cleanup step using OASIS HLB SPE cartridges is applied. The SPE eluate is concentrated and the final volume adjusted to 1 mL with MeOH:H 2 O (10:90, v/v) before injection into LC-MS/MS. Analyses are performed using electrospray ionization (ESI) and triple quadrupole (QqQ) analyzer. The method has been validated based on the SANCO European Guidelines for representative samples that were chosen to study the influence of different matrices: high water content (tomato), high acidic content (lemon), high sugar content (raisin) and high lipidic content (avocado). Special attention has been given to minimize the degradation of some pesticides into their metabolites and the losses observed in the evaporation step. Under the optimized conditions, the recoveries were, with a few exceptions, in the range 70-110% with satisfactory precision (CV ≤ 15%). The quantification of analytes was carried out using the most sensitive transition for every compound and by "matrix-matched" standards calibration. The method can be used for the accurate determination of 52 pesticides and metabolites in one single determination step at the 0.01 mg/kg level. Confirmation of residues detected in samples is performed by an independent injection into the LC-MS/MS system by acquiring additional MS/MS transitions to that used for quantification. The acquisition of the highest number of available transitions is suggested for unequivocal confirmation of the analyte.

Research paper thumbnail of Rapid direct determination of pesticides and metabolites in environmental water samples at sub-μg/l level by on-line solid-phase extraction-liquid chromatography–electrospray tandem mass spectrometry

Journal of Chromatography A, 2001

A very rapid, multi-residual, sensitive and specific procedure for determining 35 pesticides in e... more A very rapid, multi-residual, sensitive and specific procedure for determining 35 pesticides in environmental ground and surface water in proposed. It is based on the use of solid-phase extraction (SPE) combined on-line with liquid chromatography (LC) electrospray (ESI) tandem mass spectrometry (MS-MS). Simultaneous target analysis of 29 pesticides (1 fungicide, 16 insecticides, 10 herbicides and 2 acaricides) and 6 metabolites with positive or negative ionization was reached by the direct injection of only 1.3 ml of filtered water sample, with a total analysis time of 18 min. The SPE-LC-MS-MS method was validated, obtaining good results for all compounds at 0.5 and 0.1 microg/l. Most of them could be correctly quantified at a concentration level as low as 25 ng/l. Efficiency and applicability of this method was evaluated by the analysis of several samples included in a monitoring program.

Research paper thumbnail of Multiresidue Determination of Endosulfan and Metabolic Derivatives in Human Adipose Tissue Using Automated Liquid Chromatographic Cleanup and Gas Chromatographic Analysis

Journal of Analytical Toxicology, 2002

A multiresidue method based on normal-phase liquid chromatography (LC) cleanup and gas chromatogr... more A multiresidue method based on normal-phase liquid chromatography (LC) cleanup and gas chromatography-electron capture detection-mass selective detection (GC-ECD-MSD) analysis has been developed for the determination of endosulfan and its main metabolic derivatives in human adipose tissues. Analytes were extracted by dissolving the fat samples in n-hexane, and the hexanic extracts were directly injected onto the silicagel column of the automated LC cleanup system. Purified LC extracts were analyzed by GC-ECD or GC-MSD, without any solvent exchanges or preconcentration steps. The high efficiency of the high-performance liquid chromatographic cleanup for the elimination of fats allowed to reach detection limits for all analytes at low nanograms-per-gram concentration levels. The optimized overall analytical procedure was applied to 18 selected human mammary adipose and abdominal fat tissue samples, p,p~-DDE, hexachlor0benzene, and ~-HCH were the most frequently detected compounds, and residues of endosulfansulfate and-ether were also found in several samples. All findings were confirmed by an additional GC-MS-MS analysis of the LC sample extracts.

Research paper thumbnail of Biomagnification Study on Organochlorine Compounds in Marine Aquaculture:  The Sea Bass (Dicentrarchus labrax) as a Model

Environmental Science & Technology

Biomagnification of organochlorine compounds (pesticides and polychlorinated biphenyls) through t... more Biomagnification of organochlorine compounds (pesticides and polychlorinated biphenyls) through the marine aquaculture food chain is investigated. From first-feeding, specimens of sea bass were exposed to commercial fish feed (that contained DDTs and PCBs residues) for ca. 24 months, and selected tissues (white and red muscle, liver, and visceral fat) were analyzed after 6 and 24 months of diet exposure. Data obtained showed that experimental fish tissues presented a similar contamination pattern to that of fish feed, and biomagnification processes of these compounds were proved. Additionally, commercial sea bass cultured in farms from the western Mediterranean were analyzed, their organochlorine concentrations being significantly lower than those of the 24 month old experimental fish. Thus, the exposition of human population to OCs through consumption of cultured fish would be lower than expected from experimental biomagnification studies, although red muscle presented similar OC levels in both cases, which were much higher than those of white muscle. Although levels of organochlorine compounds were found to be low, the persistence, ubiquity, and toxicity of these compounds, together with their presence in fish feed, make it necessary to monitor OC residues in the routine quality assurance programs of aquaculture activities, as this food chain is a source of these toxic compounds for human consumers. The development of sensitive analytical methodology based on GC-MS/MS has allowed for the reaching of low detection limits required to carry out the present study.