Seven-in-One Low Cost Multiplexed Heavy Metal Sensor

At a Glance

Researchers at Colorado State University have developed simple, low-cost device to detect and quantify heavy metals in liquids. This innovation can be utilized to quickly obtain low-level concentrations of heavy metals for in-field use and removes the need to send samples to a reference lab.


Heavy metal contamination is an increasing global threat to human health and ecosystems, particularly in areas lacking affordable and user-friendly detection methods. Traditional platforms for heavy metal detection are labor-intensive, expensive, and require lab facilities. Paper-based colorimetric sensors offer a simpler approach, their sensitivity limitations prevent them from meeting legislative requirements for key metals to this point. Existing preconcentration systems, on the other hand, can achieve lower detection limits, but they typically focus on analyzing only one metal at a time, making comprehensive monitoring difficult. This innovation introduces a 3D-printed preconcentration unit coupled with paper-based detection for simultaneous detection of seven metal ions at low ppb levels.


This innovation is a paper-based device to quantify heavy metals and other ions in liquid samples. This is achieved with an ionic pre-concentration system, which flows the sample through separate preconcentration paper pads. These pads capture ions from the sample as the sample flows through.

The paper pads are mounted within a foldable ‘card’. Once the sample has flowed through the paper pads, the card is folded, which brings the preconcentration pads into contact with a set of glass fiber reagent pads mounted to the opposite side of the card. The reagent pads are re-hydrated by the solution captured in the preconcentration pads, and the reagents flow from the reagent pads into the preconcentration pads. As the reagents enter the preconcentration pads, they strip the captured heavy metal ions from the pads and react, changing colors. Based on the color change, the ions are quantified.

The changing colors can be detected by naked eye, allowing this to be used as a tool for a ‘quick check’ for heavy metal contamination. Additionally, the heavy metal concentration can be quantified by a simple phone app allowing the user to take a picture of the card and receive concentrations of heavy metals.

To date, the device can achieve EPA relevant limits of detection with Nickel, Copper, Iron, Chromium, Lead, and Manganese.

Since our preconcentration is a passive, ion-based system, it is expandable to other ionic targets, as well as charged non-ionic targets. The preconcentration system is able to achieve a concentration factor of ~400X without the use of any external power.


  • Inexpensive, rapid, quantitative colorimetric assay for detection of heavy metals and other ions.


  • At-home water testing
  • Environmental water testing
  • Public health/municipality water testing
  • Safety testing in other fluids
Last Updated: May 2024
hand holding a tube with water in an outdoor setting

Available for Exclusive Licensing
TRL: 5

IP Status

US Provisional Patent filed


Charles Henry
Aryal Prakash
Jason Boes

Reference Number
Licensing Manager

Steve Foster