Testing a novel biotechnological passive sampler for monitoring atmospheric PAH pollution.

In this study we evaluated a new type of passive air sampler, the "mossphere" device, filled with a Sphagnum palustre clone. For this purpose, we compared the atmospheric levels of polyaromatic hydrocarbons (PAHs) collected using this device and those collected in conventional bulk deposition and particulate matter (PM10) samplers. All three types of samplers were exposed at 10 sites affected by different levels of pollution and located in two different climate zones. The bulk deposition/ mossphere comparison yielded a greater number of significant regressions with higher coefficients of determination than the PM10/ mossphere comparison. No significant regressions were observed for 3-ring PAHs in either comparison. The mosspheres explain ca. 50% of the variability of the concentrations of 4-, 5- and 6-ring PAHs and total PAHs detected in PM10 and ca. 70% of the corresponding concentrations detected in the bulk deposition. The use of the Sphagnum clone enables standardization of the set-up, thus making the mossphere device a good sampling tool for monitoring 4-, 5- and 6-ring and total PAHs, especially those associated with bulk deposition. The findings indicate the potential usefulness of this innovative technology for mapping PAH levels.

Plasma membrane depolarization precedes photosynthesis damage and long-term leaf bleaching in (E)-chalcone-treated Arabidopsis shoots.

The plant phenolic compound (E)-chalcone has been previously found to induce noticeable seedling size reduction and progressive de-greening (bleaching) in shoots of Arabidopsis thaliana seedlings. In this work, we demonstrate that this progressive de-greening occurring on Arabidopsis shoots after (E)-chalcone treatment, is directly linked to early plasma membrane depolarization and dramatic effects on chloroplasts structure and function. Later effects in chalcone-treated seedlings included ROS accumulation, pigment degradation, reduced photosynthetic activity, bleaching, and eventually cell death. De-greening and pigment degradation induced by (E)-chalcone were partially reversed when NaCl was added together with chalcone, which could be related to restoration of altered pH gradients. All these results suggest that rapid alteration of plasma membrane potential after chalcone treatment is a major component of the mode of action of (E)-chalcone on Arabidopsis metabolism.

Terpenoid trans-caryophyllene inhibits weed germination and induces plant water status alteration and oxidative damage in adult Arabidopsis.

trans-Caryophyllene (TC) is a sesquiterpene commonly found as volatile component in many different aromatic plants. Although the phytotoxic effects of trans-caryophyllene on seedling growth are relatively explored, not many information is available regarding the phytotoxicity of this sesquiterpenes on weed germination and on adult plants. The phytotoxic potential of TC was assayed in vitro on weed germination and seedling growth to validate its phytotoxic potential on weed species. Moreover, it was assayed on the metabolism of Arabidopsis thaliana adult plants, through two different application ways, spraying and watering, in order to establish the primary affected organ and to deal with the unknown mobility of the compound. The results clearly indicated that TC inhibited both seed germination and root growth, as demonstrated by comparison of the ED50 values. Moreover, although trans-caryophyllene-sprayed adult Arabidopsis plants did not show any effect, trans-caryophyllene-watered plants became strongly affected. The results suggested that root uptake was a key step for the effectiveness of this natural compound and its phytotoxicity on adult plants was mainly due to the alteration of plant water status accompanied by oxidative damage.

PAH detection in Quercus robur leaves and Pinus pinaster needles: A fast method for biomonitoring purpose.

Due to the complexity and heterogeneity of plant matrices, new procedure should be standardized for each single biomonitor. Thus, here is described a matrix solid-phase dispersion extraction method, previously used for moss samples, improved and modified for the analyses of PAHs in Quercus robur leaves and Pinus pinaster needles, species widely used in biomonitoring studies across Europe. The improvements compared to the previous procedure are the use of Florisil added with further clean-up sorbents, 10% deactivated silica for pine needles and PSA for oak leaves, being these matrices rich in interfering compounds, as shown by the gas chromatography-mass spectrometry analyses acquired in full scan mode. Good trueness, with values in the range 90-120% for the most of compounds, high precision (intermediate precision between 2% and 12%) and good sensitivity using only 250mg of samples (limits of quantification lower than 3 and 1.5ngg(-1), respectively for pine and oak) were achieved by the selected procedures. These methods proved to be reliable for PAH analyses and, having advantage of fastness, can be used in biomonitoring studies of PAH air contamination.

Impacto de una auditoría clínica de los carros de parada en un servicio de pediatría / Impact of clinical audit of resuscitation carts in a pediatric department

Introducción: Se ha señalado que las deficiencias en el contenido y la disposición del carro de paradas suponen un importante obstáculo en la asistencia de emergencias intrahospitalarias. El desarrollo de una auditoría clínica de los carros de parada pediátricos y la difusión de los cambios realizados pueden mejorar la asistencia de urgencias vitales intrahospitalarias. Material y método: Se realizó un estudio de intervención en el que se midió el efecto sobre el conocimiento y las habilidades del personal sanitario en el manejo de los carros de parada, antes y después de un proceso de auditoría clínica, y la posterior difusión de los cambios. Resultados: Tras la aplicación y la difusión de los cambios, el tiempo medio requerido para localizar en el carro una medicación o un elemento del material de reanimación pasó de 11,3 a 4,8 segundos. La proporción de miembros del personal que localizó correctamente los carros pasó del 52,6 al 90%, y la proporción que acertó todas las preguntas sobre el contenido pasó de un 36,8 a un 80%. Conclusiones: El desarrollo de la auditoría clínica mejoró las habilidades y los conocimientos del personal ante posibles situaciones graves en el niño hospitalizado. La mejora de la precisión y la reducción de más de la mitad del tiempo de respuesta en la localización de cada fármaco puede resultar crucial en una reanimación cardiopulmonar. Este tipo de intervenciones ha de incluir la difusión de los cambios, el análisis de las condiciones ergonómicas de los medios de trabajo y la aplicación de procesos periódicos de revisión y actualización (AU)

Introduction: Deficiencies in content and disposal of crash carts are an important obstacle in-hospital emergency care. The development of a clinical audit of pediatric resuscitation carts and diffusion of changes can improve intrahospitalary assistance. Material and methods: It was performed an interventional study to assess the effect on knowledge and abilities of clinical staff in management of resuscitation carts before and after an intervention based on a process of clinical audit Results: After the intervention, the mean time required to locate items in the resuscitation carts was reduced from 11.3 to 4.8 seconds. The proportion of staff who located correctly resuscitation carts increased from 52.6% to 90%, and the proportion of those who answered correctly all questions about content increased from 36.8% to 80%. Conclusions: Clinical audit can improve staff ability and knowledge in possible emergencies in hospitalized children. Improvement in precision and reduction of the half of time needed to find each drug could be crucial in a cardiopulmonary resuscitation. These interventions should include diffusion of changes, analysis of the ergonomic conditions, and application of periodic review and updating processes (AU)

The plant secondary metabolite citral alters water status and prevents seed formation in Arabidopsis thaliana.

Based on previous results, which showed that the secondary metabolite citral causes disturbances to plant water status, the present study is focused on demonstrating and detailing these effects on the water-related parameters of Arabidopsis thaliana adult plants, and their impact on plant fitness. Clear evidence of effects on water status and fitness were observed: plants treated with 1200 and 2400 µm citral showed decreased RWC, reduced Ψs , increased Ψw and reduced stomatal opening, even 7 days after the beginning of the experiment. Plant protection signals, such as leaf rolling or increased anthocyanin content, were also detected in these plants. In contrast, 14 days after beginning the treatment, treated plants showed signs of citral-related damage. Moreover, the reproductive success of treated plants was critically compromised, with prematurely withered flowers and no silique or seed development. This effect of citral on fitness of adult plants suggests a promising application of this natural compound in weed management by reducing the weed seed bank in the soil.

Evaluation of serum myostatin and sclerostin levels in chronic spinal cord injured patients.

STUDY DESIGN: Case-control study. OBJECTIVES: To assess serum myostatin levels, bone mineral density (BMD), appendicular skeletal muscle mass (ASMM) and serum sclerostin levels in chronic spinal cord injured (SCI) patients and healthy controls. SETTING: SCI centre in Italy. METHODS: Blood samples, whole-body bioelectrical impedance analysis and BMD measurement with the ultrasound technique at the calcaneus level were taken from patients suffering from chronic SCI (both motor complete and incomplete) and healthy control subjects. RESULTS: A total of 28 SCI patients and 15 healthy controls were enrolled. Serum myostatin levels were statistically higher (P<0.01) in SCI patients compared with healthy controls. Similar results were found comparing both the motor complete and the motor incomplete SCI subgroups to healthy controls. Serum sclerostin was significantly higher in patients with SCI compared with healthy controls (P<0.01). BMD, stiffness and mean T-score values in SCI patients were significantly lower than those in healthy controls. Serum myostatin concentrations in the motor complete SCI subgroups correlated only with serum sclerostin levels (r(2)=0.42; P=0.001) and ASMM (r(2)=0.70; P=0.002) but not in healthy controls. DISCUSSION: Serum myostatin and serum sclerostin are significantly higher in chronic SCI patients compared with healthy controls. They are potential biomarkers of muscle and bone modifications after SCI. This is the first study reporting an increase in serum myostatin in patients suffering from chronic SCI and a correlation with ASMM.

Citral induces auxin and ethylene-mediated malformations and arrests cell division in Arabidopsis thaliana roots.

Citral is a linear monoterpene which is present, as a volatile component, in the essential oil of several different aromatic plants. Previous studies have demonstrated the ability of citral to alter the mitotic microtubules of plant cells, especially at low concentrations. The changes to the microtubules may be due to the compound acting directly on the treated root and coleoptile cells or to indirect action through certain phytohormones. This study, performed in Arabidopsis thaliana, analysed the short-term effects of citral on the auxin content and mitotic cells, and the long-term effects of these alterations on root development and ethylene levels. The results of this study show that citral alters auxin content and cell division and has a strong long-term disorganising effect on cell ultra-structure in A. thaliana seedlings. Its effects on cell division, the thickening of the cell wall, the reduction in intercellular communication, and the absence of root hairs confirm that citral is a strong phytotoxic compound, which has persistent effects on root development.

Blank and sample handling troubleshooting in ultratrace analysis of alkylphenols and bisphenol A by liquid chromatography tandem mass spectrometry.

Blank contamination is a notorious problem in the ultratrace analysis of alkylphenols and bisphenol A. The achievement of low detection limits is complicated due to the high background signals. Furthermore, overestimations and underestimations in the analytical results can occur when blank levels are not stable. Thus, a review of sources of blank contamination in this type of analysis was carried out. Several sources of contamination were identified and useful guidelines are proposed for the determination of these compounds in water samples by liquid chromatography coupled with mass spectrometry. The system contamination was maintained below 0.09 ng (reagent blank) for all compounds and below 0.003 µg L(-1) (procedure blank). The main improvement was obtained by using LC-MS grade solvent in the mobile phase and PTFE syringe filters for the filtration of the sample extracts. Sample handling aspects such as filtration and storage of the water samples were also considered. The filtration of the samples should be avoided because both contamination and adsorption problems were observed when different kinds of filters were assayed. The refrigerated storage of water samples should be limited to 5 days (without addition of methanol) or 8 days (with 5% methanol).

Determination of alkylphenols and bisphenol A in seawater samples by dispersive liquid-liquid microextraction and liquid chromatography tandem mass spectrometry for compliance with environmental quality standards (Directive 2008/105/EC).

A fast, simple, sensitive and green analytical chemistry method for the simultaneous determination of alkylphenols (4-tert-octylphenol, 4-octylphenol, 4-n-nonylphenol, nonylphenol) and bisphenol A in seawater was developed and validated. The procedure was based on a dispersive liquid-liquid microextraction (DLLME) of a small volume of seawater sample (30 mL) using only 100 µL of 1-octanol, combined with liquid chromatography-electrospray ionization tandem mass spectrometry in negative mode (LC-ESI-MS/MS). The matrix effect was studied and compensated using deuterated labelled standards as surrogate standards for the quantitation of target compounds. The analytical features of the proposed method were satisfactory: repeatability and intermediate precision were <10% and recoveries were around 84-104% for all compounds. Uncertainty assessment of measurement was estimated on the basis of an in-house validation according to EURACHEM/CITAC guide. Quantitation limits of the method (MQL) ranged between 0.005 and 0.03 µg L⁻¹, therefore the levels established in the Directive 2008/105/EC were achieved. The applicability of the proposed method was demonstrated analyzing seawater samples from different sites of A Coruña (Northwest of Spain). The analyses showed the presence of all compounds at levels between 0.035 (bisphenol A) and 0.14 µg L⁻¹ (nonylphenol).

Evaluación de un protocolo de intercambio terapéutico de antidepresivos de segunda generación: resultados clínicos / Assessing a Therapeutic Exchange Protocol for Second-generation Antidepressants: Clinical Results

Objetivo Diseñar un protocolo de intercambio terapéutico de antidepresivos y evaluarlo clínicamente a través de variables como: grado de cumplimiento, frecuencia de casos con aumento clínicamente significativo en la escala de morbilidad psicofarmacológica Udvalg-für-Kliniske-Undersogelser (UKU), análisis de eventos adversos, análisis de la evolución global de la puntuación en la UKU y grado de aceptación de los pacientes; objetivos secundarios fueron correlacionar aspectos del tratamiento psicofarmacológico con el grado de morbilidad farmacoterapéutica y evaluar el impacto clínico de medidas de optimización farmacoterapéuticas. Método El protocolo se diseñó de acuerdo con una revisión bibliográfica y fue aprobado por la Comisión de Farmacia y Terapéutica. Se realizaron, sobre una muestra de 30 pacientes seleccionados secuencialmente, 3 mediciones (basal, a las 48-72h y a las 1-3 semanas) en las que se cuantificó la morbilidad farmacoterapéutica mediante la escala UKU y la Impresión Clínica Global, implantando medidas de optimización farmacoterapéutica en aquellos sujetos con niveles de morbilidad farmacoterapéutica elevada. Resultados El grado de cumplimiento fue del 73,3%. Un paciente experimentó un aumento ≥ 25% en la escala UKU y otro paciente experimentó un evento adverso. La puntuación final en la escala UKU alcanzó la significación estadística en comparación con las medidas realizadas a las 48-72h (p=0,032) y con la medida basal (p=0,007). El grado de aceptación de los pacientes fue del 90%. El impacto de las medidas de optimización sobre el nivel de morbilidad farmacoterapéutica fue clínica y estadísticamente significativo (p<0,001).Conclusiones El protocolo propuesto presenta una amplia aceptación y puede considerarse seguro para su implementación en un hospital general (AU)

Objective To design a therapeutic exchange protocol for antidepressants and clinically assess variables, such as compliance level, frequency of cases with clinically significant increase on the Udvalg-für-Kliniske-Undersogelser (UKU) psychopharmacological scale, adverse effects analysis, overall analysis of UKU rating development and patients’ level of acceptance. Secondary objectives were to correlate psychopharmacological treatment aspects with the pharmacological morbidity level, and evaluate the clinical impact of pharmacotherapeutic optimisation measures. Method The protocol is designed in accordance with a bibliographical review, which was approved by the Pharmacy and Therapeutics Commission. Sequential study was carried out with a sample of 30 patients. Three measurements were taken (base line, at 48–72h and at 1–3weeks) to calculate the pharmacotherapeutic morbidity with the UKU rating scale and the Global Clinical Impression. Pharmacotherapeutic optimisation measures were used for those patients with high pharmacotherapeutic morbidity levels. Results The compliance level was 73.3%. One patient experienced ≥25% increase on the UKU rating scale and another patient suffered from an adverse effect. The final UKU rating reached statistical significance compared with the measurements taken at 48–72h (P=.032) and with the base line measurement (P=.007). Patient acceptance was 90%. The impact of optimisation measurements on the pharmacotherapeutic morbidity level was clinically and statistically significant (P<.001).Conclusions The proposed protocol has been widely accepted and it is quite certain that it is to be introduced in at a general hospital level (AU)

Assessing a therapeutic exchange protocol for second-generation antidepressants: clinical results.

OBJECTIVE: To design a therapeutic exchange protocol for antidepressants and clinically assess variables, such as: compliance level, frequency of cases with clinically significant increase on the Udvalg-für-Kliniske-Undersogelser (UKU) psychopharmacological scale, adverse effects analysis, overall analysis of UKU rating development and patients' level of acceptance. Secondary objectives were to correlate psychopharmacological treatment aspects with the pharmacological morbidity level, and evaluate the clinical impact of pharmacotherapeutic optimisation measures. METHOD: The protocol is designed in accordance with a bibliographical review, which was approved by the Pharmacy and Therapeutics Commission. Sequential study was carried out with a sample of 30 patients. Three measurements were taken (base line, at 48-72 hours and at 1-3 weeks) to calculate the pharmacotherapeutic morbidity with the UKU rating scale and the Global Clinical Impression. Pharmacotherapeutic optimisation measures were used for those patients with high pharmacotherapeutic morbidity levels. RESULTS: The compliance level was 73.3%. One patient experienced ≥25% increase on the UKU rating scale and another patient suffered from an adverse effect. The final UKU rating reached statistical significance compared with the measurements taken at 48-72 hours (P=.032) and with the base line measurement (P=.007). Patient acceptance was 90%. The impact of optimisation measurements on the pharmacotherapeutic morbidity level was clinically and statistically significant (P<.001). CONCLUSIONS: The proposed protocol has been widely accepted and it is quite certain that it is to be introduced in at a general hospital level.

Development of an environmental friendly method for the analysis of organochlorine pesticides in sediments.

This work proposes a pressurized hot water extraction (PHWE) followed by solid phase microextraction (SPME) and determination by gas chromatography-mass spectrometry method for the analysis of organochlorine pesticides in sediment samples. For SPME, extraction temperature and time, desorption temperature and desorption time, and effect of an organic modifier were studied. For PHWE, parameters such as organic modifier, percentage of organic modifier, temperature, and static extraction time were studied. When these parameters were selected, the figures of merit were calculated in order to assess the performance of the proposed method. Quantitative recoveries (80-115%) and satisfactory precisions were obtained. The detection and quantification limits were between 0.11 and 16 microg kg(-1) and between 0.24 and 22 microg kg(-1), respectively with good linearity between LOQs and 500 microg kg(-1) for most of the studied pesticides. The method was validated by the analysis of a reference marine sediment material (SRM 1944). The obtained results are in excellent agreement with the certificate material. Another sediment reference material (SRM 1941b), with a very low concentration of pesticides was also analyzed with good results. In addition, this method was successfully applied to the analysis of three marine sediment samples. The developed method seems to be a nearly full automated, environmental friendly, sensitive, simple and less-time consuming method. Moreover this method, look for the implementation of the principles of green analytical chemistry and has demonstrated to be suitable for the analysis of organochlorine pesticides at trace levels in environmental matrices as sediment samples.

[Assessment of a pharmaceutical interventional programme in patients on medications with renal risk]. / Evaluación de un programa de intervención farmacéutica en pacientes con medicamentos de riesgo renal.

OBJECTIVE: To compare the adaptation of medical prescriptions according to the dosage guides in patients with renal disease, before and after applying a pharmaceutical intervention programme. The secondary objectives were to prepare a guide to dosing in renal disease and to measure the prevalence of prescription of drugs with renal risk. METHOD: Non-randomised, experimental interventional study (before/after) conducted in a general hospital with 800 beds, including hospitalised patients, over the age of 18, with kidney disease and drugs with renal risk prescribed in their pharmacotherapeutic profile. The study was designed to be carried out in two descriptive cross-cutting phases (control group) and a prospective interventional cohort study (intervention group). The primary variable was the percentage non-adaptation according to the stage of renal disease. RESULTS: The study included 185 patients, 88 in the control group and 97 in the intervention group. In the intervention group, the prevalence of non-compliance before and after the intervention was 18.7 % and 2.1 %, representing a statistically significant reduction in non-adaptation of the dose. The costs saved with the pharmaceutical intervention programme were 1,939.63 euro over two months, the average saving per medication intervened amounting to 62.57 euro (CI 95 %, 23.99-101.14 euro; p = 0.02). CONCLUSIONS: The results of the study indicate that the application of a pharmaceutical care model based on the prospective validation of drugs with renal risk, very significantly improved the adaptation of dosing regimens in kidney disease.

Evaluación de un programa de intervención farmacéutica en pacientes con medicamentos de riesgo renal* / Assessment of a pharmaceutical interventional programme in patients on medications with renal risk

Objetivo: Comparar la adecuación de las prescripciones médicas según las guías de dosificación, en pacientes con enfermedad renal, antes y después de aplicar un programa de intervención farmacéutica. Los objetivos secundarios fueron la elaboración de una guía de dosificación en enfermedad renal y medir la prevalencia de prescripción de fármacos con riesgo renal. Método: Estudio experimental de intervención no aleatorizado (antes/después) realizado en un hospital general de 800 camas, que incluyó a pacientes ingresados, mayores de 18 años, con enfermedad renal y medicamentos con riesgo renal prescritos en su perfil farmacoterapéutico. El estudio se diseñó para realizarlo en dos fases: un corte transversal descriptivo (grupo control) y un estudio de intervención de cohortes prospectivo (grupo de intervención). La variable principal fue el porcentaje de inadecuación posológica según el grado de enfermedad renal. Resultados: El estudio incluyó a 185 pacientes, 88 en el grupo control y 97 en el de intervención. En el grupo de intervención la prevalencia de incumplimiento antes y después de la intervención fue del 18,7 y el 2,1 %, lo que supone una reducción estadísticamente significativa en la inadecuación posológica. El coste evitado con el programa de intervención farmacéutica fue de 1.939,63 euros en 2 meses; la media por cada medicamento en el que se intervino fue de 62,57 euros (intervalo de confianza del 95 %, 23,99-101,14 euros; p = 0,02). Conclusiones: Los resultados del estudio indican que la aplicación de un modelo de atención farmacéutica, basado en la validación prospectiva de los medicamentos con riesgo renal, mejora de forma muy significativa la adecuación de las pautas posológicas en enfermos renales (AU)

Objective: To compare the adaptation of medical prescriptions according to the dosage guides in patients with renal disease, before and after applying a pharmaceutical intervention programme. The secondary objectives were to prepare a guide to dosing in renal disease and to measure the prevalence of prescription of drugs with renal risk. Method: Non-randomised, experimental interventional study (before/after) conducted in a general hospital with 800 beds, including hospitalised patients, over the age of 18, with kidney disease and drugs with renal risk prescribed in their pharmacotherapeutic profile. The study was designed to be carried out in two descriptive cross-cutting phases (control group) and a prospective interventional cohort study (intervention group). The primary variable was the percentage non-adaptation according to the stage of renal disease. Results: The study included 185 patients, 88 in the control group and 97 in the intervention group. In the intervention group, the prevalence of non-compliance before and after the intervention was 18.7 % and 2.1 %, representing a statistically significant reduction in non-adaptation of the dose. The costs saved with the pharmaceutical intervention programme were 1,939.63 euro over two months, the average saving per medication intervened amounting to 62.57 euro (CI 95 %, 23.99-101.14 euro; p = 0.02). Conclusions: The results of the study indicate that the application of a pharmaceutical care model based on the prospective validation of drugs with renal risk, very significantly improved the adaptation of dosing regimens in kidney disease (AU)

A study of large-volume on-column injection GC-ECD for the ultratrace analysis of organochlorine pesticides in water.

In this work, a large-volume on-column injection method for the analysis of 21 organochlorine pesticides, including HCH isomers, DDT derivatives and cyclodiene derivatives, was optimized. The solvent selected to carry out the study was ethyl acetate and the injection volume was 100 microl. Some factors were introduced in a Plackett-Burman design to determine their influence in the vaporization efficiency. The significant factors were then studied by a univariate procedure and sorted according to their importance on the response. The effect of the injection conditions on the peak resolution was also noted. The conditions selected according to sensitivity and resolution were: initial oven temperature 75 degrees C, injection speed 20 microl s(-1), solvent vapor exit (SVE) valve closure time 60 s, initial pressure 100 kPa and isothermal oven time 1 min. Analytical characteristics expressed in terms of precision, linear range, and limit of detection have been determined and compared with those obtained by splitless injection. The degradation of endrin and p,p'-DDT thermolabile pesticides was evaluated for both injection techniques. Finally the developed method was successfully applied to the ultratrace analysis of pesticides in natural waters. With this purpose a micro liquid-liquid extraction method using 2 ml of ethyl acetate to extract 10 ml of water sample was proposed. Recoveries between 69 and 107% were obtained with a very good precision (0.2-1.3%) for the studied pesticides, except for p,p'-DDD. Detection limits between 0.3 and 25 ng l(-1), which fulfill the limits established by the new water directive 2008/105/EC, were achieved. The MLLE method was compared with the SPE method by the analysis of some water samples using both procedures, and good concordance was obtained.

Pressurized hot water extraction coupled to solid-phase microextraction-gas chromatography-mass spectrometry for the analysis of polycyclic aromatic hydrocarbons in sediments.

A fully automated, environmentally friendly, simple, and sensitive method was developed for the analysis of polycyclic aromatic hydrocarbons (PAHs) in sediment samples. The procedure is based on pressurized hot water extraction (PHWE) followed by solid-phase microextraction (SPME) and determination by gas chromatography-mass spectrometry. For PHWE, parameters such as organic modifier, percentage of organic modifier, temperature, and static extraction time were studied. For SPME, extraction temperature and time, desorption temperature and time, splitless time, ionic strength adjustments, and effect of an organic modifier were studied. When these parameters were selected, the figures of merit were calculated. The detection and quantification limits were between 0.4-15 microg kg(-1) and 1.2-51 microg kg(-1), respectively. The linearity of the method was assessed spiking sediment samples at seven levels of concentration ranged between 2.5 microg kg(-1) and 500 microg kg(-1) for most of the studied PAHs. The method was validated by two concentration levels reference marine sediment materials (SRM 1944 and SRM 1941b). The obtained results are in very good agreement with the certificate materials. The developed method seems to be suitable for the analysis of PAHs at ultratrace levels in environmental matrices as sediment samples.

A multivariate study of the programmed temperature vaporization injection-gas chromatographic-mass spectrometric determination of polycyclic aromatic hydrocarbons Application to marine sediments analysis.

The trace analysis of polycyclic aromatic hydrocarbons (PAHs) in environmental matrices requires highly sensitive and selective methods. The use of large-volume injection in gas chromatography with mass spectrometry detection allows the improvement of the sensitivity. In this work, one of the most popular large-volume injectors, programmed temperature vaporization (PTV)-splitless injection, was optimized to determine 26 alkylated and non-alkylated PAHs at ultratrace levels. The injection conditions that use two different injection volumes, 10 and 25mul, were optimized applying experimental designs. Six experimental factors that could affect the vaporization efficiency were studied. Detection limits for each assayed volume were compared with splitless injection, both in full scan and in SIM mode. An improvement of 50- and 100-fold, for 10 and 25mul, respectively, was achieved for PAHs in comparison with splitless injection. Finally, the method that was optimized for 25mul was applied successfully to the analysis of a certified marine sediment SRM 1941b and a real marine sediment extracted by microwave assisted extraction.

Solid-phase microextraction-gas chromatographic-tandem mass spectrometric analysis of polycyclic aromatic hydrocarbons. Towards the European Union water directive 2006/0129 EC.

This article presents a solid-phase microextraction (SPME) procedure to determine 27 parent and alkylated polycyclic aromatic hydrocarbons (PAHs) with diverging polarities and molecular masses in various types of water samples (tap, well, superficial, and seawater). A 65-microm polydimethylsiloxane-divinylbenzene (PDMS/DVB) fiber was used, and parameters affecting the extraction procedures such as extraction temperature and time, desorption temperature and time, splitless time, effect of an organic modifier or ionic adjustment were studied. The linearity and precision of the proposed method were satisfactory. The use of GC-MS determination in the full scan mode, in the selected ion monitoring (SIM) mode, and in the GC-MS-MS mode provided the unequivocal identification and quantification of the target analytes. Moreover, the proposed SPME-GC-MS-MS method, extracting only 18 ml of sample, reached the very restrictive limits fixed by the 2006/0129 EC proposal for a new water directive to be achieved by 2015. The matrix effects were evaluated through the analysis of tap, well, superficial, and seawater. A discussion on different behaviors, a result of the matrix effects, was included. Analytical recoveries were satisfactory in all cases. The novelty of this work consisted in the wide range of analyzed PAHs, the very low detection limits that were reached, the coupling of SPME-GC-MS-MS, and the study of the matrix effect on water samples. With this developed procedure, detection limits between 0.07 and 0.76 ng l(-1) and quantification limits between 0.10 and 0.98 ng l(-1) were obtained with MS-MS detection. Moreover, the analytical recoveries for different aqueous matrices were near 100% in all cases.