Nanopartículas como herramientas analíticas y estudios toxicológicos asociados

Las nanopartículas (NPs) exhiben unas magníficas propiedades fisicoquímicas que las hacen ser excelentes candidatas para su uso en numerosos campos de aplicación incluyendo el ámbito de la Química Analítica. Con este fin, las NPs pueden emplearse como materiales sorbentes en los métodos de tratamiento de muestra que constituyen la primera etapa de la mayoría de los procedimientos analíticos [1]. La enorme habilidad de adsorción superficial que muestran hacia numerosos compuestos tanto orgánicos como inorgánicos, justifica la utilización de las NPs para la extracción y preconcentración de los contaminantes de interés ambiental. Asimismo, y dada su versatilidad de aplicación, las NPs también pueden ser explotadas en otras etapas del procedimiento analítico como en la etapa de detección, para incrementar la sensibilidad de la técnica instrumental y así permitir la detección de contaminantes a bajas concentraciones. Otra faceta más negativa de las NPs pero no por ello menos importante, es la consideración de sus posibles efectos toxicológicos sobre los seres vivos y el medio ambiente. La evaluación de la Nanotoxicidad (toxicidad causada por las NPs) adquiere una importancia mayor dada la imposibilidad de comparar el comportamiento de estos nanomateriales con otros contaminantes ambientales ya estudiados cuando entran en contacto con los sistemas biológicos. Las características inherentes de las NPs junto con su interacción con otras especies presentes en su entorno, pueden condicionar y variar su toxicidad. La enorme complejidad asociada al establecimiento de efectos toxicológicos bien definidos para las NPs que se están sintetizando continuamente, junto con la variabilidad de los mismos según las condiciones del entorno, hace necesaria y casi obligatoria la investigación en este ámbito de estudio

Visual and Colorimetric Sensing of Metsulfuron-Methyl by Exploiting Hydrogen Bond-Induced Anti-Aggregation of Gold Nanoparticles in the Presence of Melamine

Various highly sensitive and selective analytical methods have been used to monitor metsulfuron-methyl residue in the environment. However, these methods involve costly instruments and complex, time-consuming operations performed in laboratories. Here, a rapid, convenient, and sensitive colorimetric sensor based on anti-aggregation of gold nanoparticles (AuNPs) is demonstrated for the rapid detection of metsulfuron-methyl in agricultural irrigation water. The AuNPs could be induced to aggregate in the presence of melamine and exhibited a distinct color change from wine-red to blue. The aggregation was suppressed by a strong hydrogen-bonding interaction between metsulfuron-methyl and melamine. The differences of the absorbance at 523 nm (ΔA523) and the color change was linearly related to metsulfuron-methyl concentration over the range 0.1–100 mg/L, as observed visually and by UV-vis (Ultraviolet-visible) spectrometry. The detection limit of the sensor was as low as 0.05 mg/L (signal/noise = 3), and was used to determine metsulfuron-methyl in spiked water and in agricultural irrigation water samples. Recoveries were in the range of 71.2–100.4%, suggesting that the colorimetric sensor was suitable for the determination of metsulfuron-methyl in agricultural water samples

Visual and Colorimetric Sensing of Metsulfuron-Methyl by Exploiting Hydrogen Bond-Induced Anti-Aggregation of Gold Nanoparticles in the Presence of Melamine

Various highly sensitive and selective analytical methods have been used to monitor metsulfuron-methyl residue in the environment. However, these methods involve costly instruments and complex, time-consuming operations performed in laboratories. Here, a rapid, convenient, and sensitive colorimetric sensor based on anti-aggregation of gold nanoparticles (AuNPs) is demonstrated for the rapid detection of metsulfuron-methyl in agricultural irrigation water. The AuNPs could be induced to aggregate in the presence of melamine and exhibited a distinct color change from wine-red to blue. The aggregation was suppressed by a strong hydrogen-bonding interaction between metsulfuron-methyl and melamine. The differences of the absorbance at 523 nm (ΔA523) and the color change was linearly related to metsulfuron-methyl concentration over the range 0.1–100 mg/L, as observed visually and by UV-vis (Ultraviolet-visible) spectrometry. The detection limit of the sensor was as low as 0.05 mg/L (signal/noise = 3), and was used to determine metsulfuron-methyl in spiked water and in agricultural irrigation water samples. Recoveries were in the range of 71.2–100.4%, suggesting that the colorimetric sensor was suitable for the determination of metsulfuron-methyl in agricultural water samples