Genetic and phenotypic findings in 34 novel Spanish patients with DDX3X neurodevelopmental disorder.

DDX3X is a multifunctional ATP-dependent RNA helicase involved in several processes of RNA metabolism and in other biological pathways such as cell cycle control, innate immunity, apoptosis and tumorigenesis. Variants in DDX3X have been associated with a developmental disorder named intellectual developmental disorder, X-linked syndromic, Snijders Blok type (MRXSSB, MIM #300958) or DDX3X neurodevelopmental disorder (DDX3X-NDD). DDX3X-NDD is mainly characterized by intellectual disability, brain abnormalities, hypotonia and behavioral problems. Other common findings include gastrointestinal abnormalities, abnormal gait, speech delay and microcephaly. DDX3X-NDD is predominantly found in females who carry de novo variants in DDX3X. However, hemizygous pathogenic DDX3X variants have been also found in males who inherited their variants from unaffected mothers. To date, more than 200 patients have been reported in the literature. Here, we describe 34 new patients with a variant in DDX3X and reviewed 200 additional patients previously reported in the literature. This article describes 34 additional patients to those already reported, contributing with 25 novel variants and a deep phenotypic characterization. A clinical review of our cohort of DDX3X-NDD patients is performed comparing them to those previously published.

Supported liquid membrane-protected molecularly imprinted beads for the solid phase micro-extraction of triazines from environmental waters.

In this work, a novel methodology based on the combination of MIP technology with micro solid-phase extraction in a hollow fibre device for the trace enrichment and cleanup of triazines in environmental waters is described. All parameters affecting both migration of triazines from samples to the lumen of the fibre and rebinding into MIP sites have been carefully optimized. Final conditions included, addition of 20% NaCl to the sample to produce salting-out effect, extraction of analytes during 45min with orbital stirring at 750rpm, and then washing the fibre with toluene during 5min to allow selective recognition of triazines before elution in HPLC inserts containing 450µL of a methanol/acetic acid mixture (95/5, v/v). Under optimum conditions, quantitative recoveries for simazine, cyanazine, atrazine, propazine and terbutylazine, were achieved both in surface, ground and tap water samples, with relative standard deviations lower than 10.6%, and limits of detection in the low ngL(-1) concentration level.

Supported liquid membrane-protected molecularly imprinted beads for micro-solid phase extraction of sulfonamides in environmental waters.

In this work, molecularly imprinted polymer (MIP) beads have been prepared and evaluated for the development of a supported liquid membrane-protected micro-solid phase extraction method for the analysis of sulfonamides (SAs) in aqueous samples. The performance of MIP beads was firstly evaluated in cartridges by conventional solid-phase extraction for the simultaneous analysis of SAs. Afterward, beads were packed into a polypropylene hollow fiber protected by an organic solvent immobilized in the pores of the capillary wall. During the process, the analytes were extracted from the aqueous sample to the immobilized organic solvent and then selectively retained by the MIP beads located inside the capillary. The effect of various experimental parameters as sample pH, time and stirring-rate among others, were studied for the establishment of optimum rebinding conditions. Relative recoveries for all sulfonamides tested in river and reservoir water samples by the proposed method using 100mL water sample spiked with 50µg L-1 of each sulfonamide were within 70-120%, with a relative standard deviation (RSD) <10% (n=3). The detection limits (LODs) were within 0.2-3µgL(-1), depending upon the sulfonamide and the type of water used.

Molecularly imprinted polymer for the extraction of parabens from environmental solid samples prior to their determination by high performance liquid chromatography-ultraviolet detection.

An analytical methodology incorporating a molecularly imprinted solid-phase extraction procedure (MISPE) has been developed for the determination of parabens in environmental solid samples. Four different polymers were prepared combining the use of acetonitrile or toluene as porogen, and 4-vinylpyridine (VP) or methacrylic acid (MAA) as monomer, using benzylparaben (BzP) as a template molecule. Although all the polymers were able to recognize the template in rebinding experiments, the MIP prepared in toluene using MAA showed better performance. This polymer was also capable of recognizing other parabens (methyl, ethyl, isopropyl, propyl, isobutyl, butyl and benzylparaben) allowing to develop an appropriated MISPE procedure for this family of compounds. The extraction of the parabens from environmental solid samples was performed by ultrasonic assisted extraction in small columns (SAESC), and this procedure next to MISPE as clean-up step followed by HPLC-UV determination was successfully used for the determination of parabens in soil and sediment samples of different locations. Recoveries ranging from 80% to 90% have been achieved depending on the compound and the samples, and limits of detection (LODs) were under 1 ng g(-1) for all the compounds, making this method suitable for the determination of parabens in environmental solid matrices. The method was further applied to the determination of paraben contents in real samples, founding levels up to 11.5 ng g(-1) in sea sediments.

Molecularly imprinted polymeric fibers for solid-phase microextraction.

Solid-phase microextraction (SPME) is widely used in analytical laboratories for the analysis of organic compounds, thanks to its simplicity and versatility. However, the current commercially available fibers are based on nonselective sorbents, making difficult in some cases the final determination of target compounds by chromatographic techniques. Molecularly imprinted polymers (MIPs) are stable polymers with selective molecular recognition abilities, provided by the template used during their synthesis. In the present work, a simple polymerization strategy allowing the obtainment of molecularly imprinted polymeric fibers to be used in SPME is proposed. Such a strategy is based on the direct synthesis of molecularly imprinted polymeric fibers (monoliths) using silica capillaries as molds, with silica being etched away after polymerization. The system propazine:methacrylic acid was used as a model for the preparation of molecularly imprinted fibers, and its ability to selectively rebind triazines was evaluated. Variables affecting polymer morphology (i.e., polymerization time, fiber thickness) and binding-elution of target analytes (i.e., solvents, time, temperature) were studied in detail. The imprinted fiber showing the best performance in terms of selectivity and affinity for triazines was successfully applied to the extraction of target analytes from environmental and food samples.

Molecularly imprinted polymers for solid-phase extraction and solid-phase microextraction: recent developments and future trends.

Molecularly imprinted polymers (MIPs) are synthetic polymers having a predetermined selectivity for a given analyte, or group of structurally related compounds, that make them ideal materials to be used in separation processes. In this sense, during past years a huge amount of papers have been published dealing with the use of MIPs as sorbents in solid-phase extraction, namely molecularly imprinted solid-phase extraction (MISPE). Although the majority of these papers were restricted to describe the use of different templates for different applications, several attempts proposing new alternatives to minimize the inherent drawbacks of the preparation and use of MIPs (i.e. template bleeding, tedious synthesis procedure, etc.) have been reported. Thus, this paper does not pretend to be a collection of MISPE-related papers but to give an overview on the significant attempts carried out during recent years to improve the performance of MIPs in solid-phase extraction. In addition, the use of MIPs packed in high performance liquid chromatography (HPLC) columns for the direct injection of crude sample extracts and the preparation of imprinted fibres for solid-phase microextraction will be also discussed.

Semi-covalent imprinted polymer using propazine methacrylate as template molecule for the clean-up of triazines in soil and vegetable samples.

A semi-covalent imprinted polymer was prepared by precipitation polymerisation using propazine methacrylate as template molecule, ethylene glycol dimethacrylate as cross-linker and toluene as porogen. After removal of propazine by basic hydrolysis of the covalent bond, the optimum loading, washing and elution conditions for the solid-phase extraction of the selected triazines were established. The binding sites present in the polymeric matrix were characterised by fitting the experimental results of several rebinding studies to the Langmuir-Freundlich isotherm. Subsequently, an analytical methodology based on molecularly imprinted solid-phase extraction (MISPE) was developed for the determination of several triazinic herbicides in soil and vegetable samples. Following this procedure, a good degree of clean-up of the sample extracts was easily achieved, allowing the HPLC-UV determination of selected triazines in complex samples at low concentration levels.

HPLC imprinted-stationary phase prepared by precipitation polymerisation for the determination of thiabendazole in fruit.

A molecularly imprinted polymer (MIP) tailored for the HPLC determination of the fungicide thiabendazole (TBZ) has been synthesised in one single preparative step by precipitation polymerisation in an acetonitrile/toluene co-solvent, using TBZ as template molecule, methacrylic acid as functional monomer and divinylbenzene-80 as crosslinker. The imprinted polymer particulates obtained were characterised by scanning electron microscopy and nitrogen sorption porosimetry. These analyses showed clearly that spherical polymer particulates (polymer microspheres) with narrow size distributions (average particle diameter approximately 3.5 microm) and well-developed pore structures had been produced. The imprinted microspheres were packed into a stainless steel HPLC column (50 x 4.6 mm id) and evaluated as an imprinted stationary phase. The imprinting effect was demonstrated clearly, i.e., the column was observed to bind TBZ selectively, and the effect of different chromatographic parameters (e.g., temperature, flow-rate and elution solvents) on TBZ retention/elution studied. Under optimised conditions, the TBZ-imprinted column was used for the HPLC-fluorescence (HPLC-F) determination of TBZ directly from orange (both whole fruit and juice), lemon, grape and strawberry extracts at low concentration levels in less than 15 min, without any need for a clean-up step in the analytical protocol.

Selective high performance liquid chromatography imprinted-stationary phases for the screening of phenylurea herbicides in vegetable samples.

Molecularly imprinted polymers (MIPs) for the determination of phenylurea herbicides have been synthesized by polymerisation of the appropriated reagents mixture within the pores of preformed spherical silica particles leading to a silica-MIP composite material. Subsequently, the silica matrix was etched away resulting in MIP beads which can be considered the "mirror image" of the original silica mold. The MIP particles were packed in stainless steal HPLC columns (125mmx4.6mm I.D.) and the materials were evaluated as imprinted-stationary phases for phenylurea herbicides. The imprinting effect of the originated specific binding sites for the selective recognition of phenylurea herbicides was clearly demonstrated. An efficient separation of a mixture of phenylurea herbicides in two groups, with or without a methoxy group in the chemical structure, was achieved and well shaped and defined peaks were obtained. Finally, the optimum imprinted column (prepared using linuron as template, 2-(trifluoromethyl)-acrylic acid as monomer, 72h of polymerisation time and the subsequent dissolution of silica matrix) was used for the LC-UV screening of phenylurea herbicides directly from vegetable sample extracts without any previous clean-up step at low concentration level in less than 10min.

Evaluation of new selective molecularly imprinted polymers prepared by precipitation polymerisation for the extraction of phenylurea herbicides.

Three different molecularly imprinted polymers (MIPs) have been prepared by precipitation polymerisation using linuron (LIN) or isoproturon (IPN) (phenylurea herbicides) as templates and methacrylic acid (MAA) or trifluormethacrylic acid (TFMAA) as functional monomers. The ability of the different polymers to selectively rebind not only the template but also other phenylurea herbicides has been evaluated. In parallel, the influence of the different templates and functional monomers used during polymers synthesis on the performance of the obtained MIPs was also studied through different rebinding experiments. The experimental binding isotherms were fitted to the Langmuir-Freundlich isotherm allowing to describe the kind of binding sites present in the imprinted polymers under study. It was concluded that TFMAA-based polymer using IPN as template presents the best properties to be used as a selective sorbent for the extraction of phenylurea herbicides.

Clean up of phenylurea herbicides in plant sample extracts using molecularly imprinted polymers.

Two different molecularly imprinted polymers (MIPs) were prepared by precipitation polymerization using linuron or isoproturon (phenylurea herbicides) as templates and trifluormethacrylic acid as functional monomer. These materials were used as selective sorbents in the development of molecularly imprinted solid-phase extraction (MISPE) procedures for the determination of several phenylurea herbicides (fenuron, metoxuron, chlortoluron, isoproturon, metobromuron, and linuron) in plant samples extracts. The MISPE procedures were fully optimized and applied to the clean up of selected phenylurea herbicides in carrot, potato, corn, and pea sample extracts and finally determined by HPLC-UV at 244 nm. Although a high degree of clean up was obtained, a decrease of the MIP recognition capabilities was observed in subsequent runs. Thus, a previous clean up protocol based on the use of a non-imprinted polymer was used to prevent the loss of MIP performance and to ease the removal of interferences. Following this procedure, namely two-step MISPE, matrix compounds were almost completely removed by the non-imprinted polymer retaining the ability of MIPs to selectively rebind target analytes unaltered. The developed MISPE procedures allowed the screening of phenylurea herbicides in plant samples at concentration levels required by established European maximum residue limits.

Molecularly imprinted polymers: towards highly selective stationary phases in liquid chromatography and capillary electrophoresis.

Molecularly imprinted polymers (MIPs) are synthetic polymers with a predetermined selectivity for a given analyte, or group of structurally related compounds, that make them ideal materials to be used in separation processes. In this sense, it is not surprising that the first applications of MIPs were as tailor-made chiral stationary phases in liquid chromatography. However, peak broadening and tailing, especially of the more retained enantiomers, were observed. Accordingly, this paper gives an overview of the attempts carried out during the recent years to improve the chromatographic performance of MIPs in liquid chromatography and capillary electrophoresis as well as the more recent applications. We conclude that MIPs are very promising materials to be used as selective stationary phases in chromatography although further developments are necessary in order to fully exploit their potential.

Characterisation and quality assessment of binding sites on a propazine-imprinted polymer prepared by precipitation polymerisation.

In this paper, the Langmuir-Freundlich isotherm (LF) is used to characterise a propazine-imprinted polymer obtained by precipitation polymerisation (MIP-P). Different rebinding studies were carried out allowing to explain the different interactions taking place between the molecularly imprinted polymer and six triazinic herbicides (desisopropylatrazine, desethylatrazine, simazine, atrazine, propazine and prometryn). The LF fitting parameters obtained (total number of binding sites, heterogeneity index and mean binding affinity) were compared to those obtained in a previous work for a propazine-imprinted polymer prepared by bulk polymerisation (MIP-B). From that study, it was concluded that precipitation polymerisation yielded polymers with a more homogeneous binding site distribution and higher affinity constants.

Correcting sensitivity drift during long-term multi-element signal measurements by solid sampling-ETV-ICP-MS.

Solid sampling-electrothermal vaporisation-inductively coupled plasma-mass spectrometry (SS-ETV-ICP-MS) is an attractive technique for the direct simultaneous determination of trace elements in solid samples and especially in long-term studies (i.e. assessment of the homogeneity of reference materials). However, during these studies a downward drift in the instrument sensitivity has been observed due likely to deposits on the sampling and skimmer cones and on the ion lens of the mass spectrometer. Accordingly, in this paper, several means of correcting and/or suppressing sensitivity drift are proposed and evaluated for the monitoring of Cd, Cu, Hg, Mn, Pb, Sb, Se, Sn, Tl, U and V in different reference materials of inorganic and organic (biological) origin. From that studies, the combination of the use of the argon dimer as internal standard together with a modification in the ETV-ICP connection tube seems to be the best mean of getting stable sensitivity during at least 60 consecutive ETV runs.

Clean-up of triazines in vegetable extracts by molecularly-imprinted solid-phase extraction using a propazine-imprinted polymer.

An analytical methodology based on a molecularly imprinted solid-phase extraction (MISPE) procedure was developed for the determination of several triazines (atrazine, simazine, desethylatrazine (DEA), desisopropylatrazine (DIA), and propazine) in vegetable samples. A methacrylic acid-based imprinted polymer was prepared by precipitation polymerisation using propazine as template and toluene as porogen. After removal of the template by Soxhlet extraction, the optimum loading, washing, and elution conditions for MISPE of the selected triazines were established. The optimised MISPE procedure was applied to the extraction of the selected triazines in pea, potato, and corn sample extracts and a high degree of clean-up was obtained. However, some remaining interferences, non-specifically and strongly bound to the polymeric matrix, appeared in the chromatogram, preventing quantification of DIA in potatoes and DIA, DEA, and propazine in corn samples. Thus, a new clean-up protocol based on the use of a non-imprinted polymer for removal of these interferences prior to the MISPE step was developed. By following the new two-step MISPE procedure, the matrix compounds were almost completely removed, allowing the determination of all the triazines selected at concentration levels below the established maximum residue limits, making the developed procedure suitable for monitoring these analytes in vegetable samples.

Molecular recognition in a propazine-imprinted polymer and its application to the determination of triazines in environmental samples.

An analytical methodology for the determination of triazines in environmental samples incorporating a molecularly imprinted solid-phase extraction (MISPE) process using a propazine-imprinted polymer was developed. Two different polymers were prepared using acetonitrile or toluene as porogen, and their optimum loading, washing, and elution conditions were established. Although both polymers were able to recognize several chlorotriazines (propazine, atrazine, simazine, desethylatrazine, and desisopropylatrazine), the polymer prepared in toluene showed the best performance and was also capable of recognizing a methylthiotriazine (prometryn). A binding study carried out in this polymer demonstrated that it possesses heterogeneous binding sites with different binding abilities. From this study, it was also concluded that desethylatrazine and desisopropylatrazine displace the other triazines at high concentrations, including the template molecule. The accuracy and selectivity of the MISPE process developed was verified using a certified reference material for drinking water containing atrazine and simazine among other commonly used pesticides. Finally, the MISPE procedure was successfully applied to the cleanup of drinking and groundwater, soil, and corn sample extracts, and the triazines were determined by micellar electrokinetic chromatography.

Molecularly imprinted polymers: new molecular recognition materials for selective solid-phase extraction of organic compounds.

During the last few years molecularly imprinted polymers have appeared as new selective sorbents for solid-phase extraction of organic compounds in different samples. Molecular imprinting technology involves the preparation of a polymer with specific recognition sites for certain molecules. Once the polymer has been obtained, it can be used in solid-phase extraction protocols, where a careful selection of the most appropriate solvents to be used in the different steps (sample loading, washing and elution) is needed in order to extract the target analyte selectively. This review describes the state of the art of this methodology, including the preparation of imprinted polymers, a process description for molecularly imprinted solid-phase extraction, as well as more recent applications. It is concluded that molecularly imprinted solid-phase extraction is a powerful tool to selectively isolate certain analytes, and future advances are to be expected in order to widen the field of application.

Degradation of atrazine and several organophosphorus pesticides in oranges.

The degradation of atrazine and four organophosphorus pesticides (chlorpyriphos, fenamiphos, methidathion and methyl-parathion) in oranges was studied. Oranges were immersed in a Milli-Q water solution spiked with 10 mg litre-1 of each pesticide for one day, allowing their adsorption on the orange peel. Then, the oranges were rinsed with Milli-Q water and left outdoors to expose them to natural ambient conditions for two weeks. In parallel, an aqueous solution containing 1 mg litre-1 of each pesticide was placed in a Pyrex flask, which was tightly closed, and exposed to the same ambient conditions. Both samples (orange peel and Milli-Q water) were analyzed periodically by gas chromatography coupled to a nitrogen-phosphorus detector. The pesticide degradation in both samples could be described using a first-order degradation curve. Half-lives varied from 14.5 to more than 30 days in aqueous solution and from 2.3 to 4.1 days in oranges for organophosphorus pesticides, while those for atrazine were 3.1 days and 14.2 days, respectively. The presence of some organophosphorus degradation products in water samples after storage under the above conditions was confirmed by gas chromatography-mass spectrometry.

Microwave-assisted extraction method for the determination of atrazine and four organophosphorus pesticides in oranges by gas chromatography (GC).

A simple and rapid microwave assisted extraction (MAE) method is presented for the determination of atrazine and four organophosphorus pesticides (parathionmethyl, chlorpyriphos, fenamiphos and methidathion) in orange peel. The experimental variables that affect the MAE method, such as temperature, sample quantity, extraction time, nature and volume of organic solvents, were optimized. The MAE method was optimized using an experimental design. The results suggest that temperature and sample quantity are statistically significant factors. It was concluded that the five pesticides could be efficiently extracted from 1.5-2.5 g of orange peel with 10 mL of hexane/acetone (1: 1) mixture at 90 degrees C in 9 min with microwave power set at 50% (475 W). After optimization these factors, recoveries ranged from 93 to 101% with a relative standard deviation ranging from 1 to 3%. The extracts were analyzed by gas chromatography with a nitrogen-phosphorus detector (GC-NPD).