Abstract
One in three people worldwide does not have access to safe drinking water. Notably, heavy-metal ions (HMIs) are major water pollutants threatening human health because of their severe toxicity, even at trace levels. Efficient HMI detection thus plays a major defense against metal poisoning by enabling early pollution warning and efficient regulatory enforcement. However, it remains a formidable challenge to accurately detect these pollutants on site at ultratrace levels in a cost- or time-effective manner. Here, we introduce an efficient, portable sensor to concurrently quantify five different HMIs down to the sub-nanomolar level by sulfiding them on a superhydrophobic surface. Sulfidation serves as a colorimetric reaction while the superhydrophobic surface concentrates analytes for sensitive visual detection. Our superhydrophobic concentrator (SPOT) sensor can be made portable by being integrated with a smartphone application to quantify HMIs in <8 min and at $0.02 per analysis. Decentralizing water monitoring by using our SPOT design is crucial to ensuring that clean water is accessible to everyone.
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•We introduce an efficient, portable sensor to decentralize heavy-metal-ion testing•The sensor quantifies five different heavy-metal ions down to the sub-nanomolar level•A mobile app is developed for on-site detection in 8 min and at $0.02/analysis•Our easy-to-operate sensor helps to monitor water quality on a routine basis
Accessing safe drinking water is still a major global challenge because of rising water pollution. Among various water pollutants, heavy-metal ions (HMIs) with serious toxicities are the most prevalent because of rapid industrialization and urbanization. From the recent Flint water crisis, it is obvious that water testing should be decentralized and accessible to everyone to promote safe water quality as well as to identify potential contamination for prompt remediation. Here, we design an efficient, portable sensor to concurrently detect five HMIs at concentrations one million times lower than current permissible limits set by the World Health Organization and US Environmental Protection Agency. When combined with a smartphone application, our sensor is highly mobile and swiftly detects these pollutants within 8 min at 90% accuracy. With a cost of about $0.02 per analysis, our design will expedite the decentralization of water monitoring for everyone to access clean water, a key Sustainable Development Goal established by the United Nations.
Access to clean water is a basic human right and necessary for the development of civilization. However, current reliance on centralized water monitoring retards the identification of potential water pollution crises, often only after irreversible health consequences are developed. Here, we develop an efficient, portable sensor to concurrently detect ultratrace levels of multiple heavy-metal-ion species, a major class of water pollutant linked to severe cytogenotoxicity. Notably, our sensor enables on-site detection of these toxins within 8 min and at $0.02 per analysis.