Development of highly sensitive and selective bisphenol A sensor based on a cobalt phthalocyanine-modified carbon paste electrode: application in dairy analysis.

The development of an accurate, sensitive and selective sensor for the detection of bisphenol A (BPA) based on the incorporation of a new phthalocyanine derivative, cobalt phthalocyanine, C,C,C,C-tetracarboxylic acid-polyacrylamide (CoPc-PAA) into a carbon-paste matrix is presented using voltammetry and constant potential techniques. The influence of measuring parameters such as pH and scan rate on the analytical performance of the sensor was evaluated. Several kinetic parameters such as electron transfer number (n), charge transfer coefficient (α), electrode surface area (A) and diffusion coefficient (D) were also calculated. Under optimum conditions, particularly at pH 7.2, the BPA sensor resulted in a wide linear range from 25 × 10-11 M to 2.5 × 10-7 M and a limit of detection as low as 63.5 pM. Based on these findings, it can be concluded that our sensor can be substantially utilized for detecting BPA in spiked milk samples.

Potentiometric electronic tongue to resolve mixtures of sulfide and perchlorate anions.

This work describes the use of an array of potentiometric sensors and an artificial neural network response model to determine perchlorate and sulfide ions in polluted waters, by what is known as an electronic tongue. Sensors used have been all-solid-state PVC membrane selective electrodes, where their ionophores were different metal-phtalocyanine complexes with specific and anion generic responses. The study case illustrates the potential use of electronic tongues in the quantification of mixtures when interfering effects need to be counterbalanced: relative errors in determination of individual ions can be decreased typically from 25% to less than 5%, if compared to the use of a single proposed ion-selective electrode.

T-shaped plasmonic array as a narrow-band thermal emitter or biosensor.

A T-shaped plasmonic array is proposed for application as an effective thermal emitter or biosensor. The reflection and thermal radiation properties of a T-shaped array are investigated theoretically. The angular dependent reflectance spectrum shows a clear resonant dip at 0.36 eV for full polar angles. No other significant localized resonant mode is found in the investigated spectral range from 0.12 eV to 0.64 eV. According to the Kirchhoff's law, the thermal radiation of the proposed structure can lead to a sharp peak at 3.5 microm with low sideband emission. We have also found that the T-shaped structure filled with organic material such as PMMA with different thicknesses (10 nm -50 nm) can lead to significant shift of the resonance wavelength. Thus, the T-shaped structure can also be used as a good sensor for organic materials.