Polyaniline coated micro-capillaries for continuous flow analysis of aqueous solutions

The inner walls of fused silica micro-capillaries were successfully coated with polyaniline nanofibres using the “grafting” approach. The optical response of polyaniline coatings was evaluated during the subsequent redoping–dedoping processes with hydrochloric acid and ammonia solutions, respectively, that were passed inside the micro-capillary in continuous flow. The optical absorbance of the polyaniline coatings was measured and analysed in the wavelength interval of [300–850 nm] to determine its optical sensitivity to different concentrations of ammonia. It was found that the optical properties of polyaniline coatings change in response toammonia solutions in a wide concentration range from 0.2 ppm to 2000 ppm. The polyaniline coatings employed as a sensing material for the optical detection of aqueous ammonia have a fast response time and a fast regeneration time of less than 5 seconds at room temperature. The coating was fully characterised by Scanning Electron Microscopy, Raman Spectroscopy, absorbance measurements and kinetic studies. The response of the coatings showed very good reproducibility, demonstrating that this platform can be used for the development of micro-capillary integrated sensors based on the inherited sensing properties of polyaniline

A printed and microfabricated sensor device for the sensitive low volume measurement of aqueous ammonia

The measurement of low concentrations of ammonia in small sample volumes is required in biological, biomedical and environmental measurement applications. However, achieving this without instrumentation remains challenging. Here, sensor devices for the measurement of ammonia in a liquid were developed. These were based on the fabrication of polyaniline nanoparticle films onto screen printed interdigitated electrodes using inkjet printing and their integration into a polymer microfabricated device with polytetrafluroethylene membrane and air flow path between the membrane and the sensor. Samples of ammonia in phosphate buffered saline of 52 mL were measured using electrochemical impedance. While water vapour and ions from the buffer did result in a decrease in sensor impedance, this was eradicated by displacementof the headspace above the sensor with air. This, in combination with the adjustment of the sample to pH to 11 allowed the quantification of ammonia from 0 to 200 mM with a limit of detection of 25 mM. The device has the potential to be used for sensitive, low volume measurement applications of ammonia at point-of-test and point-of-care

Reply to 'Comment on "overcoming misconceptions in quantum mechanics with the time evolution operator"'

This article presents experimental results demonstrating the performance of an erbium-doped silica fiber as a remote temperature sensor in the interval from 20C to 200C. The sensor is based on the change in the fluorescence intensity ratio of two spectral bands as a function of temperature. The green fluorescence signal was generated by up-conversion processes in the erbium-doped fiber pumped at 975 nm. A radiometric analysis was applied to the erbium-doped fiber to evaluate its performance as a temperature sensor, and the results from this analysis were compared against other rare-earth-doped fiber sensors that utilize the intensity ratio technique. Copyright " Taylor & Francis Group, LLC.",,,,,,"10.1080/01468030.2010.485293",,,"http://hdl.handle.net/20.500.12104/44183","http://www.scopus.com/inward/record.url?eid=2-s2.0-77954667413&partnerID=40&md5=7d031ef4127b38aae9e4a06ddd8e1bb6",,,,,,"4",,"Fiber and Integrated Optics",,"27

Remote temperature sensor based on the up-conversion fluorescence power ratio of an erbium-doped silica fiber pumped at 975 nm

This article presents experimental results demonstrating the performance of an erbium-doped silica fiber as a remote temperature sensor in the interval from 20C to 200C. The sensor is based on the change in the fluorescence intensity ratio of two spectral bands as a function of temperature. The green fluorescence signal was generated by up-conversion processes in the erbium-doped fiber pumped at 975 nm. A radiometric analysis was applied to the erbium-doped fiber to evaluate its performance as a temperature sensor, and the results from this analysis were compared against other rare-earth-doped fiber sensors that utilize the intensity ratio technique. Copyright © Taylor & Francis Group, LLC

Pressure monitoring over surfaces with sensitive paint by optical spectroscopy and intensity-based methods

We present experimental results of monitoring pressure over samples painted with paint called Pressure Sensitive Paint (PSP), employing optical spectroscopy and imaging analysis. An electronic system to control pressure is implemented to restricted low pressure monitoring of the samples with PSP. The surface under analysis is excited with 370 nm wavelength (UV). The signal of fluorescence generated at 580 nm is correlated to variation of pressure over the interval of 4 to 200 kPa. As a complement, a set of images is acquired in the same interval of pressure. The images are processed and then lead to a set of histograms obtained from the samples images. We assess the transfer function of the system analyzing the histograms and the spectral response curves. © 2009 SPIE

Pressure affects transcription profiles of Methanocaldococcus jannaschii despite the absence of barophilic growth under gas-transfer limitation

We present experimental results of monitoring pressure over samples painted with paint called Pressure Sensitive Paint (PSP), employing optical spectroscopy and imaging analysis. An electronic system to control pressure is implemented to restricted low pressure monitoring of the samples with PSP. The surface under analysis is excited with 370 nm wavelength (UV). The signal of fluorescence generated at 580 nm is correlated to variation of pressure over the interval of 4 to 200 kPa. As a complement, a set of images is acquired in the same interval of pressure. The images are processed and then lead to a set of histograms obtained from the samples images. We assess the transfer function of the system analyzing the histograms and the spectral response curves. " 2009 SPIE.",,,,,,"10.1117/12.852083",,,"http://hdl.handle.net/20.500.12104/43852","http://www.scopus.com/inward/record.url?eid=2-s2.0-73849144364&partnerID=40&md5=6a697bf17f01722ff31a01c14c270fc4",,,,,,,,"Proceedings of SPIE - The International Society for Optical Engineering",,,,"7499",,"Scopus",,,,,,"Imaging characterization; Pressure sensitive paints; Spectroscopy",,,,,,"Pressure monitoring over surfaces with sensitive paint by optical spectroscopy and intensity-based methods",,"Conference Paper" "45615","123456789/35008",,"Galván Ramírez, M.L., Center for Tropical Disease Research, University of Guadalajara, Jalisco, México.; Sánchez Vargas, G., Center for Tropical Disease Research, University of Guadalajara, Jalisco, México.; Vielma Sandoval, M., Center for Tropical Disease Research, University of Guadalajara, Jalisco, México.; Soto Mancilla, J.L., Center for Tropical Disease Research, University of Guadalajara, Jalisco, México.",,"Galvan Ramirez, M.L