{'fraction_non_alphanumeric': 0.04607329842931937, 'fraction_numerical': 0.0010471204188481676, 'mean_word_length': 5.593103448275862, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A Cost-Effective, Impediometric Na+-Sensor in Fluids

A crucial parameter in the body-fluid analysis is Na+-ions. Preferably realized as a small wearable, mostly the fabrication method, size, and costs prevented ion-selective devices to enter the big realm of IoT applications. This letter reports a printed, electrochemical sensor system for measuring Na+-ions in liquids. We designed, simulated, optimized, fabricated, and experimentally evaluated the sensor structures. Employing electrochemical impedance spectroscopy on a printable, dielectric ion-selective membrane, reproducible 2-electrode-measurement results are achieved in a biological-relevant mM-range. The cross-sensitivity toward K+-ions, dynamic range, and drift are investigated, and a robust measurement scheme is derived. The flexible, low-cost approach can enable new Internet-of-Things and point-of-care applications in biomedicine such as sweat analysis and environmental monitoring.