Table 1.
Ethanol sensor concepts and their advantages and disadvantages—a comparison.
| Method | Advantages (+) and Disadvantages (−) | |
|---|---|---|
| Chromatographic methods [38,39] | (+) | Most sensitive and accurate method [40,41] |
| (−) | Very high acquisition and operating costs [40,41], especially for smaller companies | |
| (−) | Well-trained operator necessary due to difficult handling of the method [40] | |
| Optical sensors [42,43] | (+) | Wide fields of application due to large measuring ranges (2–50 vol% [42], 5–50 vol% [43]) |
| (−) | High LoD (1.5 vol% [42], 2 vol% [43]) | |
| (−) | Significant cross-sensitivity to pH [42] | |
| (−) | Dye leaching over time possible [41] | |
| Microbial [44] and enzymatic [45] biosensor | (+) | Measuring range: 0.05–5 mmol/L [44], 0.1–5 mmol/L [45], after dilution also usable for alcoholic beverages [44,45] |
| (−) | Microbial and enzymatic activity depends on different factors (e.g., temperature [44,45], pH [45]) | |
| (−) | Poor long-term stability due to loss of microbial and enzymatic activity over time [44,45] | |
| Hydrogel-based sensor (presented in this work) | (+) | Wide measuring range (up to 50 vol%) |
| (+) | Low LoD (0.060–0.56 vol%) | |
| (+) | No relevant salt or pH cross-sensitivity | |
| (+) | Low-cost sensor (~10€/Sensor) | |
| (+) | Small size, even more miniaturizable | |
| (+) | In-line process capability | |
| (−) | Measurement uncertainty must be improved | |