Titrant 5

Determination of alcoholic strength of the wine samples was performed by electronic density meter coupled with near infrared spectrometer (DMA 4500 and Alcolyzer, Patent Anton Paar® (66 ); Anton Paar, Austria). Wine samples with a volume of 200 mL were distillated at ADCS—Automated Distillation Control System (Eurofins, Nantes, France), operated by the ADSC V1.1.9.0 software. Karl Fischer DL31 volumetric titrator (Mettler Toledo, Greifensee, Swizterland) operated by LabX light titration v2.6 software (Mettler Toledo, Greifensee, Swizterland) was used for the determination of the distillate water content (% w/w) in all obtained distillates in order to calculate the alcoholic strength (% w/w) and yield of each performed distillation. Eurokarl Windows v.1.0.0.0 software (Eurofins, Nantes, France) was used for transfer of the obtained alcoholic strength data to the ADSC V1.1.9.0 software (Eurofins, Nantes, France). Reagents used for the Karl-Fischer titration were Titrant 5, Solvent and 1% water standard for the standardization procedure of the solvent were obtained from Merck (Darmstadt, Germany). The requirements for the distillation procedure are described in the OIV method (OIV-MA-AS311-05:R2011) (67 ).

The reference method for determining the water content of many substances is Karl Fischer titration. It is effective in determining the water content from a few ppm to very high values close to 100%. The analysis consists of the oxidation of sulfur dioxide with a methanolic hydroxide solution. Determination of water in the tested polymer gel films was performed using the Karl Fisher Mettler Toledo titrator. The measurement was carried out using the volumetric method. The mentioned method was developed by the system of the device. The analysis was carried out using Titrant 5, a two-component reagent for Karl Fisher titration Aquastar, Merck, and a solvent of the mentioned company. The measurement was started by filling the titration cell with solvent to a volume of 40 mL. Then, after selecting the previously developed method, the apparatus was prepared for determination. After the instrument was brought to anhydrous conditions by adding a titrant to a constant drift, the instrument was ready for analysis. The polymer film was weighed and placed in the titration cell. After 5 min of mixing the sample in the solvent with a magnetic stirrer, the system of the device automatically began the determination of water released from the sample. For each series of films, the determination was repeated 3 times.