Usefulness of palladium impregnated magnetite nanoparticles for polyphenol determination.

Palladium impregnated magnetite nanoparticles (Pd-Fe3O4NPs) have been synthesized and used as reusable catalyst for the fluorometric determination of polyphenols in wines. The method is based on the decrease of the indocyanine green fluorescence, which is ascribed to its oxidation by dissolved oxygen in the presence of the nanoparticles, and the inhibition of the fluorescence decrease by polyphenols, which is proportional to the polyphenol concentration. The dynamic range of the calibration graph is 0.

Automatic determination of polyphenols in wines using laccase and terbium oxide nanoparticles.

The analytical usefulness of the combined use of laccase, terbium oxide nanoparticles (Tb4O7NPs) and 8-hydroxypyrene-3-sulphonate trisodium (HPTS) for the determination of polyphenol compounds in wine samples is described. The system is based on the temporal inhibition by polyphenols on the decrease of the HPTS fluorescence in the presence of laccase and on the activating effect of Tb4O7NPs, which increase the reaction rate of the system, shortening analysis times. The method has been developed in a microplate format using an automatic reader, reaching a sample throughput of 35 samples h(-1).

Application of Tb(4)O(7) nanoparticles for lasalocid and salicylate determination in food analysis.

The usefulness of Tb(4)O(7) nanoparticles (NPs) as analytical reagents using sensitized luminescence as a detection system is described for the first time, and the results obtained are compared with those obtained using Tb(III) ions. Two drugs used in veterinary practice, namely, lasalocid (LAS) and salicylate (SAL), have been chosen as model analytes to carry out this study. The experimental conditions for these systems have been optimized, and their analytical features were obtained.

Determination of monensin in milk samples by front-surface long-wavelength fluoroimmunoassay using nile blue-doped silica nanoparticles as labels.

A heterogeneous immunoassay for monensin determination in milk samples using a tracer formed by anti-monensin antibodies bound to nile blue (NB)-doped silica nanoparticles (NPs), 96-well microplates as solid supports and long-wavelength fluorescence measurements is described for the first time. The assay relies on the competition of the monensin present in the samples with a monensin-bovine serum albumin conjugate, which was immobilized onto the well surface, for the active sites of anti-monensin antibodies. After subsequent incubation and washing steps, the fluorescence of the bound tracer fraction is measured onto the dry surface of the well.

High throughput bioassays using nanoparticles.

An overview of the usefulness of different nanoparticles to improve the features of high throughput separation and individual and multiplexed detection bioassays is presented. Although the development of microarray and microfluidic systems has expanded the capabilities of these high throughput assays, the combined use of NPs and these devices has provided them with new applications in drug discovery, proteomic and genomic studies, and clinical diagnosis. This article reviews the wide application field of magnetic, gold, silver, semiconductor and other nanoparticles in high throughput bioassays.

Long-wavelength fluorescence polarization immunoassay: determination of amikacin on solid surface and gliadins in solution.

The versatility of the fluorescence polarization immunoassay (FPIA) is increased by using two long-wavelength labels, Nile Blue and a ruthenium(II) chelate. The first label has been used to study the potential of FPIA on a solid surface using dry reagent technology. The aminoglycoside antibiotic amikacin has been used as an analyte model, and the method has been applied to the analysis of serum samples.

Determination of fluoroquinolones in milk samples by postcolumn derivatization liquid chromatography with luminescence detection.

A liquid chromatography (LC) method with luminescence detection for the determination of eight quinolone antibiotics is reported. The system encompasses three consecutive steps: (a) chromatographic separation using reverse-phase mode (RP-LC), (b) postcolumn derivatization reaction, and (c) luminescence detection by monitoring fluorescence (FL) and time-resolved (TR) signals. The derivatization step is based on the reaction between quinolones and terbium(III) to form luminescent chelates, which were determined at lambda(ex) 340 and lambda(em) 545 nm (FL mode) or at lambda(ex) 281 and lambda(em) 545 nm (TR mode).

Usefulness of ytterbium(III) as analytical reagent for total sulfite determination in white wine samples.

Ytterbium(III) is used as reagent for the determination of sulfite by measuring the formation of the Yb(III)-sulfite complex through the variation of the light scattering intensity with time. The low solubility of this complex causes an efficient dispersion of the radiation at 490 nm, which is measured at 980 nm. Each kinetic datum is automatically obtained in only 0.