Organic liquids electrochemical testing

There are several aspects to conducting electrochemical tests in organic liquids that are often not encountered or important while testing in aqueous solutions. These include effects due to low solution conductivities, the importance of the water concentration in the solution, the existence of an extremely wide variety of liquid compositions, the complexity of products from electroactive organic liquids, and a lack of thermodynamic data. 

Laboratory testing can be of two types coupon testing and electrochemical testing. This section discusses the special considerations for each type of testing when organic liquids are involved. 

Since the corrosion behavior of materials in organic liquids can be influenced by low levels of water, minimizing the introduction of water from the ambient atmosphere during the introduction of samples or probes should be carefully considered. For long-term testing at sites where there is a constant turnover of solution, these effects may be small for a one-time insertion of coupons. However, if, for example, a retractable electrochemical probe is used, the solution with which it comes into contact should be flushed in order to allow it to sample the most relevant environment. 

Therefore, the filtered hexane extract was submitted to liquid-liquid partitioning with PBS and the upper organic layer was removed by evaporation. Finally, the buffer solution containing dichlorvos was analyzed by the biosensor. Dichlorvos was easily measured in ground wheat by electrochemical bioassay at levels as low as 0.05 pg/g. The method was peer-validated by two laboratories, and the results of the validation test are reported in Table 29.2. 

The barrier properties of the specimen coated with fluoro-organic compounds were evaluated in corrosive solution using electrochemical impedance and polarisation measurements. A 0.5% NaCl solution, maintained at 40°C, was used as the corrosion test liquid. The solution was air-saturated with an air pump. The specimen was put in a holder made of methylmethacrylate and connected to a conductive wire for electrochemical measurement. The measurement area of the specimen had a diameter of 5 mm. The electrochemical impedance and polarisation measurements were taken after the corrosion potential of the specimen became constant in the NaCl... 

---