Optical Ratiometric Sensor for Alcohol Measurements

Abstract

The need for low-cost, robust alcohol sensors has increased with the renewed interest in alternative fuels as well as high-throughput screening of biological processes involving the production of ethanol. The goal of this research was to develop a miniaturized optical ratiometric ethanol sensor to be used for in situ measurements. The sensor is based on the fluorescent dye Nile Blue Chloride. When in solution, the dye exhibits a single fluorescence peak. However, a dual emission peak is observed upon physical immobilization of the dye in the hydrogel poly(ethylene glycol) dimethacrylate. The dual emission allows for ratiometric measurements, thus circumventing drawbacks associated with fluorescence intensity measurements such as signal variations due to dye bleaching, source intensity fluctuations, etc. In developing this sensor we investigated ethanol sensitivity; alcohol selectivity; response time; and cross-sensitivity with pH, polarity, and ionic strength. We found that the sensor is sensitive to a broad range of ethanol concentrations, namely 5% to 90% v/v. Due to the hydrogel's restrictive pore size, the sensor is sensitive to short-chain alcohols such as methanol, ethanol, and propanol, but lacks sensitivity to larger alcohols such as butanol and hexanol. We also found the sensor maintains full functionality after autoclaving. Sensor sensitivity to alcohol in solutions of varying ionic strength is negligible, whereas the solvent's polarity must be controlled to maintain meaningful results. The sensor is most sensitive in acidic and neutral environments, indicating promising use for yeast-based alcohol fermentations.

A New Na+‐Dependent RNA‐Cleaving DNAzyme with over 1000‐fold Rate Acceleration by Ethanol

“…However, these methods often suffer from disadvantages, such as sophisticated instrumentations, time‐consuming processes, and complicated operation steps. Therefore, researchers have explored alternative approaches with chemical and biosensors, and a few alcohol sensors based on small molecules have been reported …”

“…Therefore, researchers have explored alternative approaches with chemical and biosensors, and af ew alcohol sensors based on small molecules have been reported. [44][45][46] As EtNa shows an interesting relationship between its activity and alcohol content, we reasoned that EtNa should be a usefulp robe for alcohol content detection. To test this theory, aq uantitative assay was carried out.…”

Leveraging Material Properties in Fluorescence Anion Sensor Arrays: A General Approach

“…This is because the ratiometric approach circumvents many of the problems of the intensity-based methods such as signal variations due to dye bleaching, fluctuations in source intensity, color background of the media, and is less likely to be biased by nonspecific interactions or impurities while offering improved signal-to-noise ratio. [9,10] Ratiometric fluorescent probes and sensors have proven their value in analyses of alcohol, [11] alkali metal ions, [12] magnesium, [13] calcium, [14] heavy metals [15] such as cadmium, [16] copper, [17] silver, [18] zinc, [19] chemical warfare agents, [20] saccharides, [21] carboxylic acids, [22] and some notable examples of anions [23] such as phosphates, [24] cyanide, [25] and DNA. [26] In this conceptual study we demonstrate how a successful design of a fluorescent ratiometric probe can be upgraded to yield efficient sensors for anions and multicomponent electrolytes such as urine.…”

Diaryldistyrylpyrazines: Solvatochromic and Acidochromic Fluorophores

“…Applications range from the fuel industry to the investigation of biological tissues 8. Fluorescent probes can be used in solution7c or, immobilized in polymeric matrices,7a,8a in flow cells. Dyes with an emission above 550 nm are preferred for biological sensing because they do not interfere with the autofluorescence of tissues.…”