A portable lateral flow distance-based paper sensor for drinking water hardness test

• Published in: PloS one Vol. 19; no. 9; p. e0308424
• Main Authors: Liu, Yulin, Dong, Longzhan, Wu, Wenli, Ping, Jiantao, Chen, Jingbo, Hu, Qiongzheng
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 06.09.2024; Public Library of Science (PLoS)
• Subjects: Alginates - analysis; Alginates - chemistry; Alginic acid; Calcium - analysis; Calcium alginate; Calcium ions; Chelation; Drinking water; Drinking Water - analysis; Drinking Water - chemistry; Hardness; Hardness tests; Humans; Hydrogels; Magnesium; Magnesium - analysis; Methods; Phase separation; Portability; Reagents; Sensors; Smartphones; Sodium; Sodium alginate; Testing; Viscosity; Water analysis; Water hardness; Water quality; Water quality management; Water sampling; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0308424

Hardness is one of the basic parameters of water, and a high-level hardness of drinking water may be harmful to human health. Thus, it is very important to monitor drinking water hardness. In this work, a portable lateral flow distance-based paper sensor for the semi-quantitative detection of drinking water hardness is demonstrated. In the presence of Ca 2+ /Mg 2+ , the hydrogel can be formed via the chelation between sodium alginate and Ca 2+ /Mg 2+ , inducing a phase separation process. The viscosity change of the sodium alginate solution is directly related to the Ca 2+ /Mg 2+ concentration and can be determined by the water lateral flow distance on test strips. The sensor successfully realizes the quantification of Ca 2+ and Mg 2+ in the range of 0–10 mmol L -1 and 4–20 mmol L -1 , respectively. The recoveries are found varied from 95% to 108.9%. The water hardness is acceptable for drinking if the C r values lies in the range of 0.259 to 0.419, and it is high with the C r value above 0.595. Remarkably, the performance of the sensor is comparable with the commercial kit for real water samples, which avoids the subjective judgment. Overall, this method provides a portable approach for semi-quantitative detection of drinking water hardness with the merits of convenience and low cost, which shows great potential for the potential application.