Monitoring of total potassium in winemaking processes using a potentiometric analytical microsystem

Innovation in products and processes, traceability, food security and quality control are inherent challenges in agri-food sector. Trends in wine production are focused on obtaining natural wines with less chemical intervention. Following this goal, a low cost miniaturized, easy-to-use and highly automated microanalyzer to monitor total potassium in winemaking processes is presented. The microsystem monolithically integrates microfluidics as well as a potentiometric detection system and does not require any sample pretreatment. The analytical features provided are a linear range from 250 to 4000 mg L^-1 K⁺, covering all the concentrations expected in must and wine samples, a detection limit of 75 ± 12 mg L^-1 K⁺, and an adequate reproducibility and repeatability. Sample throughput is calculated at 20 h⁻¹ with a waste volume generation lower than 4 mL per analysis. The microsystem lifetime is at least 4 months. Different wine and grape juice samples have been analyzed reaching outstanding results.