The consumption of milk supplemented with probiotics decreases the occurrence of caries and the salivary concentration of hßD-3 in children.

OBJECTIVES: This study evaluated the effect of milk supplemented with Lactobacillus rhamnosus SP1 on the occurrence of caries and the salivary concentration of human ß-defensin-3 (hßD-3) in preschool children with high caries risk. MATERIALS AND METHODS: A sample of 42 children was randomly assigned to two groups; children in the intervention group were given 150 mL of milk supplemented with 107 CFU/mL of Lactobacillus rhamnosus SP1, while children in the control group were given standard milk, for 10 months. The occurrence of dental caries was assessed using the International Caries Detection and Assessment System (ICDAS), and the concentration of hßD-3 was measured in unstimulated saliva using an ELISA test at baseline and after the intervention. RESULTS: There was an increase in the number of teeth with carious lesions (dICDAS2-6 mft) in the control group, and this increase was statistically significant (p = 0.0489). The concentration of hßD-3 in saliva from the intervention group decreased from 597.91 to 126.29 pg/mL (p = 0.0061), unlike in the control group, where no change in hßD-3 salivary concentration was found. CONCLUSIONS: These findings showed that regular intake of probiotic-supplemented milk in preschool children with high caries risk decreased the occurrence of caries and the salivary levels of hßD-3. CLINICAL RELEVANCE: Our results suggest the need for developing and implementing probiotic supplementation, as adjuvants to the conventional treatments for caries and allow to considerate the salivary levels of hßD-3 as markers of oral tissue homeostasis.

Validation of the Spanish version of the "Questionnaire on the treatment of approximal and occlusal caries".

OBJECTIVES: To translate and validate a Spanish version of the "Questionnaire on the treatment of approximal and occlusal caries" as a method of collecting information about treatment decisions on caries management in Chilean primary health care services. MATERIALS AND METHODS: The original questionnaire proposed by Espelid et al. was translated into Spanish using the forward-backward translation technique. Subsequently, validation of the Spanish version was undertaken. Data were collected from two separate samples; first, from 132 Spanish-speaking dentists recruited from primary health care services and second, from 21 individuals characterised as cariologists. Internal consistency was evaluated by the generation of Cronbach's alpha, test-retest reliability was evaluated by Cohen's kappa, convergent validity was evaluated by comparing the total scale scores to a global evaluation of treatment trends and discriminant validity was evaluated by investigating the differences in total scale scores between the Spanish-speaking dentist and cariologist samples. RESULTS: Cronbach's alpha indicated an internal consistency of 0.63 for the entire scale. Cohen's kappa correlation coefficient expressed a test-retest reliability of 0.83. Convergent validity determined a Pearson's correlation coefficient of 0.24 (p < 0.01). The comparison of proportions (chi-squared) indicated that discriminant validity was statistically significant (p < 0.01), using a one-tailed test. CONCLUSIONS: The Spanish version of the "Questionnaire on the treatment of approximal and occlusal caries" is a valid and reliable instrument for collecting information regarding treatment decisions in cariology. CLINICAL RELEVANCE: The clinical relevance of this study is to acquire a reliable instrument that allows for the determination of treatment decisions in Spanish-speaking dentists.

Cost-effectiveness of probiotics and fluoride varnish in caries prevention in preschool children.

OBJECTIVES: The purpose of this study was to evaluate the cost-effectiveness of two preventive interventions aimed at increasing the proportion of caries-free preschool children of low socioeconomic status using a decision analytic model. METHODS: Two scenarios were tested, one with a school milk program (SMP) and one without (non-SMP). Fluoride varnish (FV) and a probiotic (PB) were compared to a do-nothing alternative among children in public nurseries/schools over a 4-year period. FV was applied biannually and a PB (Lactobacillus rhamnosus) added to milk powder prepared daily. A Markov decision tree model was utilized. Several sources of data were used to populate the model. Probabilistic and deterministic sensitivity analyses were performed, and a public provider perspective was used. RESULTS: In the SMP scenario, PB was more effective and less costly than FV and, compared with do-nothing, increased the proportion of caries-free children by 14.5%, with a cost of USD 12.5 per child (June 2018). PB presented an incremental cost-effectiveness ratio (ICER) or cost per extra caries-free child of USD 86.2. In the non-SMP scenario, both interventions were cost-effective. FV (compared with do-nothing) increased the percentage of caries-free children by 8.3% with an ICER of USD 338.3 and PB (compared with FV) increased the effect by 6.2% with an ICER of USD 1400.2. CONCLUSIONS: The findings showed that PB was most effective and less costly than FV in the SMP scenario only. This type of analysis and its results provide essential information for decision-makers to improve the oral health of preschool children.

Behavior of phenols and phenoxyacids on a bisphenol-A imprinted polymer. Application for selective solid-phase extraction from water and urine samples.

A molecularly imprinted polymer (MIP), obtained by precipitation polymerisation with 4-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate as cross-linker, and bisphenol-A (BPA) as template, was prepared. The binding site configuration of the BPA-MIP was examined using Scatchard analysis. Moreover, the behaviour of the BPA-MIP for the extraction of several phenolic compounds (bisphenol-A, bisphenol-F, 4-nitrophenol, 3-methyl-4-nitrophenol) and phenoxyacid herbicides such as 2,4-D, 2,4,5-T and 2,4,5-TP has been studied in organic and aqueous media in the presence of other pesticides in common use. It was possible to carry out the selective preconcentration of the target analytes from the organic medium with recoveries of higher than 70%. In an aqueous medium, hydrophobic interactions were found to exert a remarkably non-specific contribution to the overall binding process. Several parameters affecting the extraction efficiency of the BPA-MIP were evaluated to achieve the selective preconcentration of phenols and phenoxyacids from aqueous samples. The possibility of using the BPA-MIP as a selective sorbent to preconcentrate these compounds from other samples such as urine and river water was also explored.

Determination of leucine and isoleucine/allo-isoleucine by electrospray ionization-tandem mass spectrometry and partial least square regression: Application to saliva samples.

Herein we propose, for the first time, a rapid method based on flow injection analysis, electrospray ionization-tandem mass spectrometry (FIA-ESI-MS/MS) and multivariate calibration for the determination of l-leucine, l-isoleucine and L-allo-isoleucine in saliva. As far as we know, multivariate calibration has never been applied to the data from this non-separative approach. The possibilities of its use were explored and the results obtained were compared with the corresponding ones when using univariate calibration. Partial least square regression (PLS1) multivariate calibration models were built for each analyte by analyzing different saliva samples, and were subsequently applied to the analysis of another set of samples which had not been used in any calibration step. For Leu, the model worked satisfactorily with root mean square errors in the prediction step of 17%. This error can be considered acceptable and is common in methodologies that do not include a separation step. Results were compared with those obtained when univariate calibration was used, using the m/z transition 132.1 â†’ 43.0 as the quantitation variable. In this case, the obtained results were not acceptable, with RMSEP of 236%, due to the fact that saliva samples contained another compound, different to the target analytes, which also shared the same transition. Ile and aIle have the same fragmentation patterns, so quantification of the sum of both compounds was performed, with RMSEP of 14% using a PLS1 model. Similar results were obtained when a univariate calibration model using the m/z transition 132.1 â†’ 69.0 was employed. However, the use of this transition should be carefully examined when other compounds present in the matrix contribute to the analytical signal. The method increases sample throughput more than one order of magnitude compared to the corresponding LC-ESI-MS/MS method and is especially suitable as screening. When abnormally high or low concentrations of the analytes studied are obtained, the use of the method that includes separation is recommended to confirm the results.

In-capillary microextraction using monolithic polymers: application to preconcentration of carbamate pesticides prior to their separation by MEKC.

In the present work we report a novel procedure for in-capillary microextraction using a monolithic polymeric sorbent. In the proposed methodology, sample treatment takes place in the CE instrument but in a different capillary from that used for the electrophoretic separation. Polymers based on butyl methacrylate and divinylbenzene formed in situ inside a capillary column were assayed. The best results were found with the divinylbenzene-based polymers. The usefulness of the proposed procedure was checked for the determination of carbamate pesticides (Methomyl, Asulam, Carbendazim, Aldicarb, Carbetamide, Propoxur, Pirimicarb, Carbaryl, Carbofuran and Methiocarb) and three of their degradation compounds (Aldicarb sulphoxide, 2-isopropoxyphenol and alpha-naphthol) using MEKC. The optimization of the MEKC is reported, a good separation of the 13 analytes being obtained in less than 6 min. The analytical method using in-capillary microextraction was validated in terms of linearity, repeatability, precision (RSD< or =18% for 50 microg/L), and LODs (1-16 microg/L), and it revealed the usefulness of this in-capillary preconcentration procedure for the determination of analytes of intermediate polarity.

Development of a screening and confirmatory method for the analysis of polar endogenous compounds in saliva based on a liquid chromatographic-tandem mass spectrometric system.

In this paper, a high-throughput approach is proposed for the sensitive screening and the confirmatory analysis of polar compounds in saliva using a two-step approach based on a liquid chromatographic system coupled to a triple quadrupole mass spectrometer. A reversed-phase chromatographic column was used in both steps and changes in the composition of the mobile phase allowed the screening and the confirmatory analyses to be performed with the same instrumental configuration. The proposed strategy has been tested for the determination of a multiclass group of polar endogenous compounds (creatinine, polyamines and amino acids) in saliva samples. The validation of the entire procedure showed consistent results for all the compounds in both steps. Repeatability and reproducibility were evaluated for both procedures, with values below 8% in the case of repeatability and 17% in the case of reproducibility. The instrumental limits of detection were found to be between 1.22 × 10-3 and 46.1 × 10-3 mg/L for creatinine and lysine, respectively, and accuracy of the method was evaluated in terms of apparent recoveries and values were found to be between 80 and 127%. Matrix effects were evaluated and it was found that the analytical outcome was influenced by the matrix of the sample. Thus, a one-point standard addition method was used for quantification. The optimized two-step procedure was applied to saliva samples from apparent healthy volunteers. Overall, satisfactory results were obtained in both steps, demonstrating its applicability for quantitative analysis of polar endogenous compounds in this kind of matrices.

A Post-translational Metabolic Switch Enables Complete Decoupling of Bacterial Growth from Biopolymer Production in Engineered Escherichia coli.

Most of the current methods for controlling the formation rate of a key protein or enzyme in cell factories rely on the manipulation of target genes within the pathway. In this article, we present a novel synthetic system for post-translational regulation of protein levels, FENIX, which provides both independent control of the steady-state protein level and inducible accumulation of target proteins. The FENIX device is based on the constitutive, proteasome-dependent degradation of the target polypeptide by tagging with a short synthetic, hybrid NIa/SsrA amino acid sequence in the C-terminal domain. Protein production is triggered via addition of an orthogonal inducer ( i.e., 3-methylbenzoate) to the culture medium. The system was benchmarked in Escherichia coli by tagging two fluorescent proteins (GFP and mCherry), and further exploited to completely uncouple poly(3-hydroxybutyrate) (PHB) accumulation from bacterial growth. By tagging PhaA (3-ketoacyl-CoA thiolase, first step of the route), a dynamic metabolic switch at the acetyl-coenzyme A node was established in such a way that this metabolic precursor could be effectively redirected into PHB formation upon activation of the system. The engineered E. coli strain reached a very high specific rate of PHB accumulation (0.4 h-1) with a polymer content of ca. 72% (w/w) in glucose cultures in a growth-independent mode. Thus, FENIX enables dynamic control of metabolic fluxes in bacterial cell factories by establishing post-translational synthetic switches in the pathway of interest.

Sinopsis de la Situación de Salud Oral en Chile - Parte IV: Traumatismo Dentoalveolar / Synopsis of the Oral Health Situation in Chile - Part IV: Traumatic Dental Injuries

RESUMEN: Objetivo: Sintetizar los resultados de estudios epidemiológicos sobre Traumatismo Dentoalveolar (TDA) en la población chilena. Material y métodos: Se realizó una revisión sistemática de la literatura para identificar estudios poblacionales a nivel nacional, regional, provincial y comunal, además de datos de servicios dentales de atención primaria y secundaria sobre TDA en Chile. Resultados: Se incluyeron 2 estudios con representatividad nacional y 8 realizados en centros de atención en salud. A nivel nacional, la prevalencia de TDA a los 6 años fue de un 2.57%, y a los 12 años, 4.97%. En los estudios realizados en centros de salud, el diagnóstico más prevalente en dentición primaria fueron las lesiones de tejidos de soporte y en dentición permanente, la fractura coronaria. Fue más frecuente la afectación de un solo diente, y los incisivos centrales superiores fueron los dientes más afectados. Conclusiones: Los estudios representativos de la población en Chile son escasos, realizados hace más de una década y representativos sólo de la población de 6 y 12 años, lo cual pone de manifiesto la necesidad de mayor información epidemiológica sobre el TDA en la población chilena.

ABSTRACT: Aim: To summarize the evidence on epidemiological studies about traumatic dental injuries (TDI) in Chile. Methods: A systematic literature review was carried out in two databases to identify population studies at national, regional, provincial and community levels, as well as reports from primary and secondary dental care services, regarding TDI in Chile. Results: Two studies with national representation and eight studies from primary and secondary healthcare centers were included in the analysis. National prevalence for 6-year-old children was 2.57%, and 4.97% for 12-year-old children. While the most frequent diagnosis in primary dentition was traumatic injury involving tooth-supporting tissues, the most commonly reported diagnosis in permanent dentition was crown fracture. Single tooth affection was more frequent, and the upper central incisors were the most affected teeth. Conclusions: Data on representative studies about TDIs in Chile are scarce. Few studies, carried out more than a decade ago and only on 6- and 12-year-old children are available. There is a need for further epidemiological information about TDIs in Chile.

Clinical Effects of Lactobacillus rhamnosus in Non-Surgical Treatment of Chronic Periodontitis: A Randomized Placebo-Controlled Trial With 1-Year Follow-Up.

BACKGROUND: Probiotics are living microorganisms that provide beneficial effects for the host when administered in proper quantities. The aim of this double-masked placebo-controlled parallel-arm randomized clinical trial is to evaluate the clinical effects of a Lactobacillus rhamnosus SP1-containing probiotic sachet as an adjunct to non-surgical therapy. METHODS: Twenty-eight systemically healthy volunteers with chronic periodontitis were recruited and monitored clinically at baseline and 3, 6, 9, and 12 months after therapy. Clinical parameters measured included plaque accumulation, bleeding on probing, probing depths (PDs), and clinical attachment loss. Patients received non-surgical therapy, including scaling and root planing (SRP), and were assigned randomly to a test (SRP + probiotic, n = 14) or control (SRP + placebo, n = 14) group. The intake, once a day for 3 months, of an L. rhamnosus SP1 probiotic sachet commenced after the last session of SRP. RESULTS: Both test and control groups showed improvements in clinical parameters at all time points evaluated. However, the test group showed greater reductions in PD than the control. Also, at initial visits and after 1-year follow-up, the test group showed a statistically significant reduction in the number of participants with PD ≥6 mm, indicating a reduced need for surgery, in contrast to the placebo group. CONCLUSION: The results of this trial indicate that oral administration of L. rhamnosus SP1 resulted in similar clinical improvements compared with SRP alone.

Cloning and molecular ontogeny of digestive enzymes in fed and food-deprived developing gilthead seabream (Sparus aurata) larvae.

We have determined the expression pattern of key pancreatic enzymes precursors (trypsinogen, try; chymotrypsinogen, ctrb; phospholipase A2, pla2; bile salt-activated lipase, cel; and α-amylase, amy2a) during the larval stage of gilthead seabream (Sparus aurata) up to 60days after hatching (dph). Previously, complete sequences of try, cel, and amy2a were cloned and phylogenetically analyzed. One new isoform was found for cel transcript (cel1b). Expression of all enzyme precursors was detected before the mouth opening. Expression of try and ctrb increased during the first days of development and then maintained high values with some fluctuations during the whole larval stage. The prolipases pla2 and cel1b increased from first-feeding with irregular fluctuation until the end of the experiment. Contrarily, cel1a maintained low expression values during most of the larval stage increasing at the end of the period. Nevertheless, cel1a expression was negligible as compared with cel1b. The expression of amy2a sharply increased during the first week followed by a gradual decrease. In addition, a food-deprivation experiment was performed to find the differences in relation to presence/absence of gut content after the opening of the mouth. The food-deprived larvae died at 10dph. The expression levels of all digestive enzymes increased up to 7dph, declining sharply afterwards. This expression pattern up to 7dph was the same observed in fed larvae, confirming the genetic programming during the early development. Main digestive enzymes in gilthead seabream larvae exhibited the same expression profiles than other marine fish with carnivorous preferences in their juvenile stages.

Determination of triazines and dealkylated and hydroxylated metabolites in river water using a propazine-imprinted polymer.

A molecularly imprinted polymer (MIP) obtained by precipitation polymerisation using propazine as template has been employed as sorbent for the solid phase extraction of triazines and some of their hydroxylated and dealkylated metabolites from river water. Three configurations were studied: (a) use of the propazine-MIP as a selective sorbent for the extraction of triazines directly from water; (b) use of mixtures of LiChrolut EN (a polymeric sorbent of styrene divinylbenzene) and propazine-MIP as sorbent, and (c) use of propazine-MIP as a clean-up sorbent for organic extracts obtained in a prior SPE procedure with LiChrolut EN. The former two configurations imply that the analytes pass through the propazine-MIP in aqueous medium, whereas in the latter case the analytes percolate through the propazine-MIP in an organic medium coming from the previous SPE step. Different types of water were tested to assess matrix effects. The analytical characteristics of the three configurations were evaluated.

The effect of different finishing and polishing procedures on the surface gloss of Bulk-Fill resin composites

STATEMENT OF THE PROBLEM: The literature still lacks evidence regarding which polishing techniques have the ideal clinical outcomes for bulk-fill resin composites. PURPOSE: This study evaluated the surface gloss of two commercially available bulk-fill resin composites after different polishing procedures and characterized their micromorphology via scanning electron microscopy. MATERIAL AND METHODS: 80 bulk-fill compactable composite resin discs were created. The control group was left untreated, and remaining samples were subjected to different polishing techniques. Gloss units were measured and surface morphology of disc samples was assessed. The Tukey post-hoc test was used to identify any differences. RESULTS: Statistically significant differences were found between the different polishing systems applied to Filtek BulkFill Posterior and Tetric N Bulk-Fill. No differences were found when the same polishing system was applied for both resins. The highest gloss values were obtained in the control group and the ENA Shiny system; the lowest were obtained with SofLex XT and Soflex Spiral Wheels for the bulk-fill composite resins studied. CONCLUSIONS. Diamond pastes have the highest gloss behavior, followed by diamond rubber points. The systems with aluminum oxide discs present the lower gloss behavior. SEM images provided useful evidence, and future studies should include an evaluation over time.

Sinopsis de la Situación de Salud Oral en Chile - Parte II: Diagnósticos Poblacionales de Salud Oral / Synopsis or the Oral Health Situation in Chile - Part II: Oral Health Surveys

RESUMEN: Objetivo: Sintetizar los resultados sobre los estudios epidemiológicos de caries dental, enfermedad periodontal, desdentamiento y lesiones de mucosa oral de base poblacional con representatividad nacional y regional en adultos chilenos (≥15 años). Materiales y métodos: Se realizó una revisión narrativa para identificar aquellos estudios de diagnóstico de salud bucal, a nivel nacional y/o regional, en población adulta de Chile (≥15 años), con el objetivo de establecer prevalencias para las patologías bucales de mayor relevancia nacional. Resultados: Se identificaron 6 estudios de representatividad nacional y 7 estudios de representatividad regional. Se reporta una disminución en la prevalencia de caries cavitadas y de dentición no funcional, correspondiendo a un 54.6% y 27.0%, respectivamente. La prevalencia de pérdida de inserción clínica ≥4mm., es cercana al 100%. La lesión de mucosa oral más prevalente fue la estomatitis subprotésica (22.3%). Se observaron inequidades socieconómicas y culturales en la distribución de las patologías orales en la población adulta chilena. Conclusiones: Existe una alta prevalencia de enfermedad periodontal, caries, desdentamiento y lesiones de mucosa oral en adultos y adultos mayores chilenos.

ABSTRACT Aim: To synthesize results of epidemiologic national and regional studies about dental caries, periodontal diseases, tooth loss and oral mucosa lesions in Chilean adults (≥15 years- old). Methods: A narrative revision was made in order to identify epidemiologic national or regional studies in Chilean adults (≥15 years- old). The objective was to establish the prevalence of the most common oral diseases. Results: Six national and seven regional studies were identified. The prevalence of non-treated caries and non- functional dentition was reduced to 54.6% and 27.0%, respectively. The prevalence of periodontal attachment loss ≥4mm. was almost 100%. The most frequent oral mucosa lesion was denture stomatitis (22.3%). Socioeconomic and cultural disparities were observed in the distribution of oral diseases in Chilean adults. Conclusions: The prevalence of dental caries, periodontal diseases, tooth loss and oral mucosa lesions was high in Chilean adults and elderly people.

Sinopsis de la Situación de Salud Oral en Chile - Parte III: Encuestas Nacionales de Salud / Synopsis or the Oral Health Situation in Chile - Part III: National Health Surveys

RESUMEN: Este artículo realiza una revisión y síntesis de las principales encuestas poblacionales de salud en Chile. Se describen sus principales características y hallazgos con el objetivo de orientar a los profesionales odontólogos en el conocimiento de material existente para el diagnóstico odontológico objetivo, así como el impacto de la salud oral en la calidad de vida, a nivel poblacional.

ABSTRACT: This article makes a brief review and synthesis of national health surveys in Chile. The article describes the main characteristics and findings in order to guide dental professionals with the knowledge of the existing material for an objective population oral health diagnosis, as well as the impact of oral health on quality of life of the population.

Adenosine monophosphate is elevated in the bronchoalveolar lavage fluid of mice with acute respiratory toxicity induced by nanoparticles with high surface hydrophobicity.

Inhaled nanomaterials present a challenge to traditional methods and understanding of respiratory toxicology. In this study, a non-targeted metabolomics approach was used to investigate relationships between nanoparticle hydrophobicity, inflammatory outcomes and the metabolic fingerprint in bronchoalveolar fluid. Measures of acute lung toxicity were assessed following single-dose intratracheal administration of nanoparticles with varying surface hydrophobicity (i.e. pegylated lipid nanocapsules, polyvinyl acetate nanoparticles and polystyrene beads; listed in order of increasing hydrophobicity). Broncho-alveolar lavage (BAL) fluid was collected from mice exposed to nanoparticles at a surface area dose of 220 cm(2) and metabolite fingerprints were acquired via ultra pressure liquid chromatography-mass spectrometry-based metabolomics. Particles with high surface hydrophobicity were pro-inflammatory. Multivariate analysis of the resultant small molecule fingerprints revealed clear discrimination between the vehicle control and polystyrene beads (p < 0.05), as well as between nanoparticles of different surface hydrophobicity (p < 0.0001). Further investigation of the metabolic fingerprints revealed that adenosine monophosphate (AMP) concentration in BAL correlated with neutrophilia (p < 0.01), CXCL1 levels (p < 0.05) and nanoparticle surface hydrophobicity (p < 0.001). Our results suggest that extracellular AMP is an intermediary metabolite involved in adenine nucleotide-regulated neutrophilic inflammation as well as tissue damage, and could potentially be used to monitor nanoparticle-induced responses in the lung following pulmonary administration.

Analysis of pesticide residues in matrices with high lipid contents by membrane separation coupled on-line to a high-performance liquid chromatography system.

Separation through membranes coupled to an HPLC system was used as a technique for the analysis of pesticide multiresidues in samples with high lipid contents. As well as the usual procedure, in the proposed system it is possible to recirculate the sample through the membrane cell, which permits the extraction system to be applied to cases in which only a very small volume of sample is available. A procedure for pesticide multiresidue analysis in egg samples was developed as a representative example of the applicability of the proposed method. To accomplish this, the analytes (dichlorvos, dimethoate, propoxur, paraoxon, pirimicarb, atrazine, ametryne, terbutryne, azinphos-methyl, folpet) were subjected to prior extraction in a Soxhlet system, after which the extract was introduced into the membrane separation device coupled to the HPLC system. This procedure afforded clean chromatograms, hence considerably facilitating determination, and at the same time was efficient in removing macromolecular compounds. For egg samples, spiked at a concentration level of 0.750 mg/kg, recoveries ranged from 60 to 98%. The detection limits varied from 0.018 mg/kg for dichlorvos to 0.002 mg/kg for atrazine.

Analytical applications of membrane extraction in chromatography and electrophoresis.

An overview of the analytical applications of membrane-based systems for sample enrichment in chromatography and capillary electrophoresis is presented. A brief introduction to the different types of membranes and the main forces related to the transport through them is also given.

Development of a procedure for the isolation and enrichment of modified nucleosides and nucleobases from urine prior to their determination by capillary electrophoresis-mass spectrometry.

A sample treatment step based on solid-phase extraction (SPE) with polymeric sorbents has been developed for the simultaneous isolation and preconcentration of nucleosides and nucleobases from urine prior to analyses by CE-ESI-MS. In most reported methods nucleosides are isolated from urine by SPE in affinity mode, using an immobilized phenylboronic acid group, which specifically binds cis-diols. However, this is not applicable to non-cis-diol compounds. Here, different types of polymeric sorbents were evaluated for the simultaneous extraction of nucleosides and nucleobases from urine. The best results were obtained with Isolute ENV+, a hydroxylated styrene-divylbenzene polymer, whose retention capacity can be attributed mainly to hydrophobic interactions, and thus it can be applied to a broad range of compounds, regardless of whether they present or not to the cis-diol group in their structure. Other parameters such as the elution solvent and sample volume were optimized. We also studied the influence of the addition of isotopically labeled internal standards (ILISs) before or after the extraction step. The detection limits achieved were in the 0.04-0.17µg/mL range for a sample size of 2.0mL and relative standard deviations were 4-22%. The whole method developed, SPE prior to CE-ESI-MS, was applied to human urine samples from healthy volunteers. We conclude that SPE with polymeric sorbents prior to the electrophoretic CE-ESI-MS methodology constitutes a fast, valid and reliable approach for the simultaneously extraction of urinary nucleosides and nucleobases.

Occurrence of phenols and phenoxyacid herbicides in environmental waters using an imprinted polymer as a selective sorbent.

A monitoring program was developed for the environmental analysis of four phenols and three phenoxyacid herbicides in natural surface and ground water samples from the vineyard region of La Rioja (Spain). An analytical method based on molecularly imprinted solid phase extraction was developed for the determination of the impact of these compounds on the quality of environmental water samples. Different parameters were evaluated and optimized to achieve limits of detection in the 20-90 ng L(-1) range for both surface and ground water, with relative standard deviations in the 12-18% range. A comparative study of the behavior of the imprinted polymer compared with traditional sorbents (C18 and Oasis HLB) in the analysis of river water was performed. The results revealed that bisphenol-A is the most ubiquitous compound (present in more than 50% of the samples), with values up to 0.72 µg L(-1). Bisphenol-F was also detected in several samples (33% of the samples), although in concentration lower than Bisphenol-A. The herbicide 2,4-D was frequently detected in water samples (present in 33% of the samples), with concentrations above 0.1 µg L(-1) in two samples.