Publications by authors named "Marta Cruz-Vera"

The health protection while ensuring the access to safe drinking water to the entire population is one of the main objectives all over the world. In this regard, the European Union, through Directive 98/83/EC, sets the parameters and maximum allowable parametric values to ensure the quality of water intended for human consumption. The aim of this paper is to give an overview of the values established in the European Directive in comparison with other countries and organizations, such as the World Health Organization, based on toxicological justification, doing special mention to the case of pesticides, in which there is great difference between the parametric values set.

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The main objective of this Tutorial Review is to approach the modern principles and practices of Analytical Chemistry to Point-of-Care Testing (POCT) systems in order to contribute to improve both the development of new devices and the reliable application of the existing ones. In this article, after contextualization of the topic, POCT systems (POCTs) are fully defined using several approaches. The requirements of a POCT system to be a robust and reliable tool available to patients and medical workers are described as well as their desirable complementary characteristics.

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For the first time, a molecularly imprinted polymer (MIP) was synthesized by a noncovalent imprinting approach for the selective extraction of an illicit drug, LSD, from hair and urine samples. For the synthesis of MIP, an analog of LSD, was taken as a dummy template, methacrylic acid as a functional monomer, and ACN as a porogen solvent. The MIP was used for offline extraction before HPLC-MS analysis.

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Dispersive liquid-liquid microextraction (DLLME) has been proved to be a powerful tool for the rapid sample treatment of liquid samples providing at the same time high enrichment factors and extraction recoveries. A new, simple and easy to handle one step in-syringe set-up for DLLME is presented and critically discussed in this paper. The novel approach avoids the centrifugation step, typically off-line and time consuming, opening-up a new horizon on DLLME automation.

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Liquid-phase microextraction (LPME) emerged in the mid-to-late 1990s, facing up to the main shortcomings of the classical liquid-liquid extraction. Since its origin, this new technique has been in continuous development driven by its successful and widespread use in the analytical sciences. Its inherent properties, such as low sample volume requirement, high preconcentration factors achieved and excellent sample clean-up, make LPME a very useful technique for bioanalytical sample preparation.

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Dynamic liquid-phase microextraction (dLPME) using an ionic liquid as acceptor phase is proposed for the determination of six non-steroidal anti-inflammatory drugs (NSAIDs) in human urine samples for the first time. The extraction is carried out in a simple and automatic flow configuration. The chemical affinity between the extractant (1-butyl-3-methylimidazolium hexafluorophosphate) and the analytes permits a selective isolation of the drugs from the sample matrix allowing also their preconcentration.

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Antidepressants are widely used for the treatment of psychiatric disorders and therefore their monitoring in biological fluids is quite important taking into account that they can produce dangerous biochemical imbalances in toxic doses. A method for the determination of antidepressants in urine samples is presented using solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection. Home-made cartridges containing 30 mg multiwall carbon nanotubes are employed for isolation of the analytes from the sample, allowing also the preconcentration of the analytes prior to the HPLC analysis.

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A continuous-flow configuration based on sequential solid-phase extraction and derivatization is proposed for the screening of urine samples for imipramine and related metabolites. For the first time, a 50/50 (v/v) methanol/nitric acid mixture is used as both eluent and derivatizing reagent. Sample aliquots are injected into the flow manifold and driven by a water stream to an RP-C(18) column where the drugs are quantitatively retained.

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