Sistema de purificación de agua Milli-Q® Reference
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Referencias bibliográficas
| Visión general referencias | Aplicación | Pub Med ID |
|---|---|---|
| Quantification of 2-hydrazinopyridine derivatized steroid hormones in fathead minnow (Pimephales promelas) blood plasma using LC-ESI+/MS/MS D. Hala, M.D. Overturf, L.H. Petersen, D.B. Huggett J. Chromatogr. B 879 591–598 2010 Mostrar resumen Fathead minnows (Pimephales promelas) comprise a species-of-choice for the hazard assessments of various environmental contaminants, including compounds capable of disrupting endocrine function. Towards this end, the use of liquid chromatography coupled with mass spectrometry (LC–MS) and/or tandem mass spectrometry (MS/MS) is gaining common use for the quantification of steroid hormones as biomarkers of endocrine stress in small-fish toxicological studies. In this work, 2- hydrazinopyridine (2-HP) was used to derivatize and quantify the physiologically relevant steroid hormones of: 17 -hydroxypregnenolone, progesterone, 11-ketotestosterone, 11-deoxycortisol and 17 ,20 -dihydroxypregnenone, in the blood plasma of male and female fathead minnows. Liquid chromatographic separation was achieved using a WatersTM Sunfire C18 column (2.1mm×50mm with a 3.5 m particle size) and Milli-Q water:methanol (both with 0.1% formic acid) mobile phase over a gradient of 15 min. All mass analyses were conducted using electrospray ionization in the positive mode with tandem mass spectrometry (ESI+/MS/MS). This is the first such application of 2-HP derivatization for the quantifications of the structurally and functionally diverse C19 androgen of 11-ketotestosterone; C21 progestogens of 17 -hydroxypregnenolone, progesterone and17 ,20 -dihydroxypregnenone; and C21 corticosteroid of 11-deoxycortisol, in fathead minnow blood plasma. The limits of detection (LOD) were set to the lowest calibration standard that gave a signal-to-background response of ≥3, and were: 0.16 ng/ml for progesterone, 0.63 ng/ml for 17 -hydroxypregnenolone, 11-deoxycortisol and 17 ,20 - dihydroxypregnenone, and 1.25 ng/ml for 11-ketotestosterone. This study demonstrates the application of 2-HP derivatization for the analysis of a variety of steroid hormones representative of endocrine function in a species of fish commonly used in toxicological studies. | ||
| Assessment of the acute toxicity of triclosan and methyl triclosan in wastewater based on the bioluminescence inhibition of Vibrio fischeri M. Farré, D. Asperger, L. Kantiani, S. González, M. Petrovic, D. Barceló Anal Bioanal Chem 390 1999–2007 2008 Mostrar resumen In this work, the contributions of triclosan and its metabolite methyl triclosan to the overall acute toxicity of wastewater were studied using Vibrio fischeri. The protocol used in this paper involved various steps. First, the aquatic toxicities of triclosan and methyl triclosan were determined for standard substances, and the 50% effective concentrations (EC50) were determined for these compounds. Second, the toxic responses to different mixtures of triclosan, methyl triclosan, and surfactants were studied in different water matrices, i.e., Milli-Q water, groundwater and wastewater, in order to evaluate (i) the antagonistic or synergistic effects, and (ii) the influence of the water matrices. Finally, chemical analysis was used in conjunction with the toxicity results in order to assess the aquatic toxicities of triclosan and its derivative in wastewaters. In this study, the toxicities of 45 real samples corresponding to the influents and effluents from eight wastewater treatment works (WWTW) were analyzed. Thirty-one samples were from a wastewater treatment plant (WWTP) equipped with two pilot-scale membrane bioreactors (MBR), and the influent and the effluent samples after various treatments were characterized via different chromatographic approaches, including solid-phase extraction (SPE), liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS), and SPE coupled to gas chromatography–mass spectrometry (GC–MS). The toxicity was determined by measuring the bioluminescence inhibition of Vibrio fischeri. In order to complete the study and to extrapolate the results to different WWTPs, the toxicity to V. fischeri of samples from seven more plants was analyzed, as were their triclosan and methyl triclosan concentrations. Good agreement was established between the overall toxicity values and concentrations of the biocides, indicating that triclosan is one of the major toxic organic pollutants currently found in domestic wastewaters. | ||
| Extraction of extracellular polymeric substances from extreme acidic microbial biofilms A. Aguilera, V. Souza-Egipsy, P. San Martín-Úriz, R. Amils Appl Microbiol Biotechnol 78 1079–1088 2008 Mostrar resumen The efficiency of five extraction methods for extracellular polymeric substances (EPS) was compared on three benthic eukaryotic biofilms isolated from an extreme acidic river, Río Tinto (SW, Spain). Three chemical methods (MilliQ water, NaCl, and ethylenediamine tetraacetic acid [EDTA]) and two physical methods (Dowex 50.8 and Crown Ether cation exchange resins) were tested. The quality and quantity of the EPS extracted from acidic biofilms varied according to which EPS extraction protocol was used. Higher amounts were obtained when NaCl and Crown Ether resins were used as extractant agents, followed by EDTA, Dowex, and MilliQ. EPS amounts varied from approximately 155 to 478 mg g-1 of dry weight depending on the extraction method and biofilm analyzed. EPS were primarily composed of carbohydrate, heavy metals, and humic acid, plus small quantities of proteins and DNA. Neutral hexose concentrations corresponded to more than 90% of the total EPS dry weight. The proportions of each metals in the EPS extracted with EDTA are similar to the proportions present in the water from each locality where the biofilms were collected except for Al, Cu, Zn, and Pb. In this study, the extracellular matrix heavy metal sorption efficiencies of five methods for extracting EPS from eukaryotic acidic biofilms were compared. | ||
| A General Method for Constructing Optically Active Supramolecular Assemblies from Intrinsically Achiral Water-Insoluble Free-Base Porphyrins Y. Zhang, P. Chen, M. Liu Chem. Eur. 14 1793 – 1803 2008 Mostrar resumen We have developed a general method to construct optically active porphyrin supramolecular assemblies by using a simple air–water interfacial assembly process. The method involved the in situ diprotonation of the free-base porphyrins at the air–water interface and subsequent assembly under compression. We showed that two intrinsically achiral water-insoluble free-base porphyrin derivatives, 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine (H2OEP) and 5,10,15,20-tetra-p-tolyl-21H,23H-porphine (H2TPPMe), could be diprotonated when spread onto a 2.4?M hydrochloric acid solution surface, and the Langmuir–Schaefer (LS) films fabricated from the subphase exhibited strong circular dichroism (CD) absorption, whereas those fabricated from pure Milli-Q water subphase did not. The experimental data suggested that the helical stacking of the achiral porphyrin building blocks was responsible for the supramolecular chirality of the assemblies. Interestingly, such a method was successfully applied to a series of other intrinsically achiral free-base porphyrins such as 5,10,15,20-tetrakis(4-methoxyphenyl)-21H,23H-porphine (H2TPPOMe), 5,10,15,20-tetraphenyl-21H,23H-porphine (H2TPP), 5,10,15,20-tetrakis(4-(allyloxy)phenyl)-21H,23H-porphine (H2TPPOA), and 5,10,15,20-tetrakis(3,5-dimethoxyphenyl)-21H,23H-porphine (H2TPPDOMe). A possible mechanism has been proposed. The method provides a facile way to obtain optically active porphyrin supramolecular assemblies by using intrinsically achiral water-insoluble free-base porphyrin derivatives. | ||
| LC/MS/MS structure elucidation of reaction intermediates formed during the TiO2 photocatalysis of microcystin-LR M. G. Antoniou, J. A. Shoemaker, A. A. de la Cruz, D. D. Dionysiou Toxicon 51 1103–1118 2008 Mostrar resumen Microcystin-LR (MC-LR), a cyanotoxin and emerging drinking water contaminant, was treated with TiO2 photocatalysts immobilized on stainless steel plates as an alternative to nanoparticles in slurry. The reaction intermediates of MC-LR were identified with mass spectrometry (MS) at pH of Milli-Q water (pHsq = 5.7). Eleven new [M+H]+ were observed in the liquid chromatography mass spectrometry (LC/MS) chromatogram with some of them giving multiple peaks. Most of these reaction intermediates have not been reported from previous studies employing TiO2 nanoparticles at acidic conditions (pH = 4.0). Investigating the effects of pH (for 3.0<pH<7.0), toxin adsorption and initial toxin concentration on the degradation efficiency of the TiO2 photocatalytic films showed that acidic conditions are preferable for the degradation. Combined with the limited surface area of the films and the absence of additional oxidants (i.e., H2O2) the degradation was slower and more intermediate steps were identified. Possible structures of the intermediates (formed at neutral pH) after analyzing the corresponding MS/MS spectra are reported. The collision-induced dissociation of the [M+H]+ of MC-LR and the intermediates 1011.5 and 1029.5 are discussed and possible fragmentation pathways and mechanisms are also proposed. Analysis of the MS/MS spectra indicates that the fragmentation of some amino acids is less favorable because of internal interaction with free groups of adjacent amino acids. The MS/MS spectra assisted in determining hydroxylation sites, by the formation or alteration of specific product ions such as m/z 599. | ||
| Differential expression of chicken hepatic genes responsive to PFOA and PFOS L.W.Y. Yeung, K.S. Guruge, N. Yamanaka, S. Miyazaki, P.K.S. Lam Toxicology 237 111–125 2007 Mostrar resumen The effects of PFOS and PFOA on the gene expression patterns of chickens that were exposed to either PFOS or PFOA at low doses were investigated with the use of microarray techniques. Twelve Genechip Chicken Genome Arrays were used to study hepatic gene expression in 6-week-old chickens (Gallus gallus) that were exposed to either PFOA (0.1, 0.5, or 5 mg/mL), PFOS (0.02 or 0.1 mg/mL), or a saline vehicle control (0.9% NaCl in Milli-Q water) via subcutaneous implantation of a 2 mL osmotic pump for 4 weeks or for 4 weeks with a further 4 weeks of depuration. Over 240 and 480 genes were significantly affected by PFOS after 4 weeks of exposure and after 4 weeks of exposure with a further 4 weeks of depuration, respectively and over 290 and 320 genes were significantly affected by PFOA, correspondingly. For PFOS, the genes that were affected after 4 weeks of exposure were mainly related to the transport of electrons and oxygen, and the metabolism of lipids and fatty acids; while the genes that were affected after 4 weeks of exposure with a further 4 weeks of depuration were mainly related to the transport of electrons and ions, and protein amino acid phosphorylation and proteolysis. For PFOA, the genes that were affected after 4 weeks of exposure were related to the transport of ions, lipids, and electrons and cytochromes; while the genes that were affected after 4 weeks of exposure with a further 4 weeks of depuration were related to protein amino acid phosphorylation and proteolysis, the transport of ions, and the metabolism of fatty acids and lipids. The results also showed that the gene expression patterns between chickens that were treated with PFOS and those that were treated with PFOA were different, which points to the importance of the separate evaluation of the toxicities of PFOS and PFOA. Specifically, the gene expressions of CYP8B and NOV were studied. | ||
| Aligned Nanocables: Controlled Sheathing of CuO Nanowires by a Self-Assembled Tubular Glycolipid Y. Zhou, S. Kamiya, H. Minamikawa, T. Shimizu Adv. Mater 19 4194–4197 2007 Mostrar resumen Aligned nanocables, consisting of CuO nanowire cores and lipid nanotube shells, are prepared by sheathing an aligned array of CuO nanowires with a self-assembled tubular glycolipid (see figure). The sheath thickness of the nanocable is tunable by changing the incubation temperature of the lipid on the CuO nanowire. | ||
| Simultaneous determination of trace levels of ethylmercury and methylmercury in biological samples and vaccines using sodium tetra(n-propyl)borate as derivatizing agent D. Gibičar, M. Logar, N. Horvat, A. Marn-Pernat, R. Ponikvar, M. Horvat Anal Bioanal Chem 388 329–340 2007 Mostrar resumen Because of increasing awareness of the potential neurotoxicity of even low levels of organomercury compounds, analytical techniques are required for determination of low concentrations of ethylmercury (EtHg) and methylmercury (MeHg) in biological samples. An accurate and sensitive method has been developed for simultaneous determination of methylmercury and ethylmercury in vaccines and biological samples. MeHg and EtHg were isolated by acid leaching (H2SO4–KBr–CuSO4), extraction of MeHg and EtHg bromides into an organic solvent (CH2Cl2), then back-extraction into Milli-Q water. MeHg and EtHg bromides were derivatized with sodium tetrapropylborate (NaBPr4), collected at room temperature on Tenax, separated by isothermal gas chromatography (GC), pyrolysed, and detected by cold-vapour atomic fluorescence spectrometry (CV AFS). The repeatability of results from the method was approximately 5–10% for EtHg and 5–15% for MeHg. Detection limits achieved were 0.01 ng g-1 for EtHg and MeHg in blood, saliva, and vaccines and 5 ng g-1 for EtHg and MeHg in hair. The method presented has been shown to be suitable for determination of background levels of these contaminants in biological samples and can be used in studies related to the health effects of mercury and its species in man. This work illustrates the possibility of using hair and blood as potential biomarkers of exposure to thiomersal. | ||
| A thermo extraction–UV/Vis spectrophotometric method for total iodine quantification in soils and sediments B. S. Gilfedder, F. Althoff, M. Petri, H. Biester Anal Bioanal Chem 389 2323–2329 2007 Mostrar resumen Iodine in soils and sediments is a difficult element to analyze due to its volatility in acidic conditions. Traditionally it has been quantified using neutron activation analysis techniques, which, unfortunately, requires access to a nuclear reactor. We present here a simple method for solid-phase iodine analysis by thermo extraction at 1000°C and quantification by UV/Vis photometry. Samples are combusted in an oxygen stream and trapped in Milli-Q water. The extracts are then quantified by an As3+–Ce4+ spectrometric method whereby iodide catalyzes the oxidation of As3+ to As5+ and reduction of Ce4+ to Ce3+. Three standard reference materials were analyzed with excellent recoveries (97–113%) and RSDs (<5%). Moreover, the detection limit was less than 50 ng absolute iodine with a confidence limit of 95%. When applied to carbonate-rich samples from sediment traps deployed in Lake Constance we found very low iodine levels (0.8–2 mg kg-1). Despite the low concentrations, the precision of the method was consistently better than 5% RSD. However, the method needed to be slightly modified for organic and iodine-rich sediments (20–30% organic carbon) from a lake in the Black Forest by increasing the oxygen flow rate and decreasing the combustion time. Using the modified method we were able to achieve RSDs lower than 5%. | ||
| Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry Analysis of Stimulatory Drugs of Abuse in Wastewater and Surface Waters M. Huerta-Fontela, M. Teresa Galceran, F. Ventura Anal. Chem. 79 3821-3829 2007 Mostrar resumen Ultraperformance liquid chromatography coupled to electrospray tandem mass spectrometry was used for the rapid and simultaneous analysis of 15 stimulatory drugs in water. Cocaine, amphetamine-related compounds, LSD, ketamine, PCP, fentanyl, and metabolites, among the controlled drugs, and nicotine, caffeine, and their metabolites, among the noncontrolled drugs, were studied. Chromatographic separation was achieved in less than 4.5 min, with improved peak resolution and sensitivity. Identification and quantification of the compounds of interest was performed by selected reaction monitoring, using an electrospray ionization source. Isotope dilution (except for paraxanthine) was used for quantitation. Quality parameters of the method were established, and limits of quantification were obtained for controlled drugs in surface waters from 0.1 to 3.1 ng/L and in wastewaters from 0.2 to 4.0 ng/L. Run-to-run and day-to-day precisions were evaluated in different water matrixes (Milli-Q water, surface water, wastewater). To assess the presence of these drugs in real water samples, the optimized method was applied to the analysis of wastewater and surface river water. The analysis of several samples from wastewater treatment plants in northeast Spain revealed the presence of drugs such as cocaine and amphetamine-related compounds, in both influent and effluent samples. Cocaine metabolite and MDMA (ecstasy) were also found in surface waters while nicotine and caffeine were detected in all the analyzed samples. The results obtained demonstrate that the presence of these drugs in the aquatic media must be considered a matter of environmental concern. |
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| Lab Water Purification > Milli-Q® Type 1 Ultrapure Water Systems |
Milli-Q® Reference suministra agua de tipo I adaptada para ajustarse a una amplia gama de campos de investigación y permite disponer cómodamente de agua ultrapura en cualquier laboratorio. Está diseñado para ser abastecido desde una fuente de agua pretratada.
Agua Milli-Q® • Purificación optimizada
Para obtener agua ultrapura de calidad Milli-Q®, se ha optimizado por completo la secuencia de purificación. El agua se procesa a través de cartuchos de purificación Q-Gard® y Quantum® hasta alcanzar una resistividad de 18,2 MΩ.cm (a 25° C) y un TOC inferior a 5 ppb. A continuación, recircula a través de un lazo hasta el dispensador, donde un filtro específico de aplicación elimina contaminantes específicos cruciales para sus experimentos. Se dispone de una gama de módulos de purificación y de filtros específicos de aplicación que usted puede seleccionar en función de sus aplicaciones.
Fabricada solo para los sistemas Milli-Q®, la resina de intercambio iónico virgen Jetpore® se utiliza en todos los módulos de purificación Milli-Q®. Seleccionada por su excepcional rendimiento, puede capturar incluso los iones con carga más débil debido a sus capacidades cinéticas. Los dos módulos, Q-Gard® y Quantum®, incorporan también la tecnología RFID. Esto proporciona visibilidad instantánea de los parámetros del módulo y garantiza también un rendimiento seguro y óptimo de su sistema, proporcionándole una completa trazabilidad.
Comodidad • Dispensación simple y mantenimiento sencillo
Utilizando el dispensador Milli-Q® Reference,
- Ahorrará tiempo gracias a su función volumétrica, que suministra automáticamente el volumen de agua que usted solicitó.
- Preparará disoluciones sin esfuerzo con el dispensador de fácil manejo y desmontable. Su diseño ha sido concebido para adaptarse a la altura y la forma de todo el material de vidrio del laboratorio.
Su pantalla gráfica muestra información sobre la calidad del agua y el estado del sistema para asegurar que su sistema está funcionando de la manera apropiada, proporcionando las mejores condiciones de trabajo para sus experimentos. Una Guía de referencia rápida situada en la puerta del sistema de purificación de agua Mili-Q® Reference permite conseguir más información. Cartuchos de fácil sustitución y una lámpara UV de larga duración acoplada a oportunos avisos de asistencia técnica, permiten al sistema funcionar suavemente durante todo un año.
Las soluciones en línea Millitrack® e-Solutions proporcionan un mejor control de la gestión de datos, capacidades de acceso remoto al panel de control del sistema y archivado electrónico de datos históricos para su Milli-Q® Reference. Además, los ingenieros certificados del Servicio Técnico proporcionan una completa gama de servicios, entre ellos servicio técnico de validación utilizando equipo calibrado y manuales de cualificación.
Certificados de calidad
Para una completa confianza en su sistema Milli-Q® Reference, éste se entrega con un Certificado de Calibración de los medidores de la temperatura y la resistividad incorporados, y un Certificado de conformidad que asegura que se ha ensamblado y controlado siguiendo los Procedimientos normalizados de trabajo internos. Además, todos los fungibles de Milli-Q® Reference se suministran con su Certificado de calidad. El centro de fabricación tiene las certificaciones ISO® 9001 v.2000 e ISO® 14001.
Especificaciones del agua
Agua ultrapura (Tipo I) Milli-Q® Reference
| Resistividad a 25 °C1 | 18,2 MΩ•cm |
| TOC2 | ≤ 5 ppb |
| Partículas (tamaño > 0,22 µm)3 | < 1 partícula/ml |
| Bacterias3,4 | < 0,01 UFC/ml |
| Lipopolisacáridos (endotoxinas)4 | < 0,001 UE/ml |
| RNasas4 | < 1 pg/ml |
| DNasas4 | < 5 pg/ml |
| Caudal | Hasta 2 l/minuto |
| 1 La resistividad puede mostrarse sin compensación de temperatura como exige la USP 2 En las condiciones analíticas apropiadas 3 Con el filtro Millipak® 4 Con el filtro BioPak® Estos valores (validados con agua de alimentación Elix®) son típicos y pueden variar dependiendo de la naturaleza y la concentración de los contaminantes del agua de alimentación. |
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Puede solicitarse un informe sobre la conformidad de la calidad del agua del Milli-Q® Reference con la calidad del agua de Tipo I como se describe en las normas ASTM®, ISO® 3696 y CLSI® y con el agua purificada como se describe en la USP y la Farmacopea Europea.
Agua de alimentación
| Calidad del agua de alimentación | Agua Elix®, RiOs™, destilada o DI con conductividad < 100 µS/cm y TOC < 50 ppb |
| Conexión al agua de alimentación | 1,3 cm Gas M |
| Presión del agua de alimentación * | 0 – 0,3 bares |
| Temperatura del agua de alimentación | 5 – 35 °C |
| * Para una presión superior a 0,3 bares, debe estar instalado un regulador de presión antes del sistema; para presiones comprendidas entre 0 y -0,2 bares, el sistema funcionará, pero el caudal del producto puede ser menor. | |
Especificaciones del sistema
| Dimensiones (Al x An x P) | 713 x 413 x 458 mm |
| Peso en funcionamiento | 19,5 kg |
| Longitud de las tuberías de abastecimiento del dispensador | 750 mm |
| Longitud del cable de suministro eléctrico | 290 mm |
| Voltaje del suministro eléctrico | 100 – 250 V ± 10 % |
| Frecuencia de suministro eléctrico | 50 – 60 Hz ± 10 % |
| Conexión de datos | Ethernet (RJ45) |
Seguridad
Una compañía independiente y acreditada ha comprobado que el sistema Milli-Q® Reference cumple las directrices de la CE relativas a seguridad y compatibilidad electromagnética. Puede solicitarse el informe. El sistema Milli-Q® Reference está fabricado utilizando componentes y prácticas recomendadas por UL y tiene la marca cUL. El registro puede verificarse en la página web de UL (http://www.ul.com).