Seeing smells: development of an optoelectronic nose

Abstract

Recebido em 7/6/06; publicado na web em 26/3/07The development of an array of chemically-responsive dyes on a porous membrane and in its use as a general sensor for odors and volatile organic compounds (VOCs) is reviewed. These colorimetric sensor arrays (CSA) act as an "optoelectronic nose" by using an array of multiple dyes whose color changes are based on the full range of intermolecular interactions. The CSA is digitally imaged before and after exposure and the resulting difference map provides a digital fingerprint for any VOC or mixture of odorants. The result is an enormous increase in discriminatory power among odorants compared to prior electronic nose technologies. For the detection of biologically important analytes, including amines, carboxylic acids, and thiols, high sensitivities (ppbv) have been demonstrated. The array is essentially non-responsive to changes in humidity due to the hydrophobicity of the dyes and membrane.

Anchoring effect on (tetra)carboxyphenyl porphyrin/TiO2composite films for VOC optical detection

“…6 Porphyrins and other dyes have been widely used in the last decades for gas-sensitive purposes. 5,[7][8][9] Their photochemical and photophysical properties make them ideal candidates for the optical detection of analytes. Thus, they can be precisely tuned by introducing substituents in their structure or coordinating metals to the porphyrin core.…”

Molecular Interaction between Colorimetric Sensor Array and Volatile Organic Compounds Considering Density Functional Theory

“…(3) High sensitivities (ppb) have been proved both theoretically and experimentally (i.e., using amines, carboxylicacids, and thiols). (4) Thus, the CSA method has emerged as a powerful method for the analysis and evaluation of food quality and safety, which can produce a unique composite response for each sample. This helpful sensor mimics the mammalian olfactory system based on strong molecular interactions.…”

Designing solid optical sensors for in situ passive discrimination of volatile amines based on a new one-step hydrophilic PDMS preparation

“…Non-permeable polymer [2][3][4][5] can provide stability and shelf-life of the embedded dye avoiding sensor response to external parameters like humidity [6][7][8][9][10].…”