Table 4.
Main characteristics of the most important electrochemical sensors applied in CH, mainly presented in this review.
| Electrochemical Devices | Quantitative Analysis | Qualitative Analysis | Main Advantages | Main Disadvantages |
|---|---|---|---|---|
| Raman spectrometer, equipped with a potentiostatic apparatus | LOD = 5 ppm (mg/L) for melamine | ✓ | low cost measurement, no-time consuming analysis, high sensitivity, low detection of limit |
Non-electroactive pigments and organic binders cannot quantify by electrochemistry |
| Electrochemical cell, which also works like a Bragg tool | ---------------------------- | ✓ | to detect different crystallographic phases during serious corrosion events, to detect the corrosion potential Ecorr, both parameters, unequivocally provide important information on the nature of metallic corrosion phenomena |
not all the corrosion products, to which different crystallographic phases belong, have electrochemical activity, therefore the disadvantage is that there is only qualitative crystallographic information |
| Screen-Printed Electrodes (SPEs) chemically modified with Graphene Oxide (GO); GO/SPE |
See Table 3 | ✓ | Voltammetric techniques are useful to understand two important aspects, as -the chemical-physical composition of the colors; -the oxidation status and conservation conditions of metallic elements contained in organic pigments, useful to select the best restoration strategies |
Particularly useful only in the case of metals contained in inks, colored pigments and organic compounds The absence of metals makes the application of this device more difficult, as the organic component (very often) does not have a marked electrocatalytic activity |
| micro-sample coatings in Paraloid B72 film-modified electrodes, combined with | ---------------------------- | ✓ | micro-sample coatings in Paraloid B72-film provide the possibility of pre-concentrating the pigments to increase the Signal/Noise ratio, especially in the presence of traces of organic materials | micro-sample coatings in Paraloid B72-film are not so selective and for this purpose several interferences and/or passivation/fouling effects can occur during analysis/measurements |
✓ Qualitative analysis is performed; --------------: this symbol means that the specific parameter is not reported in the paper.