In marine ecosystems, high concentrations of certain nutrients such as nitrate and phosphate lead to unimpeded algal growth and low dissolved oxygen levels; conditions which are deadly for fish, shellfish, and invertebrates. Such high concentrations are also indicative of ecosystem-wide problems, and occur as a result of water stagnation, as well as through runoff from wastewater treatment plants and agricultural activities. The detection of these nutrients by rapid and robust colorimetric, paper-based detection schemes that can be used on-site is of high interest to individuals monitoring marine environments, especially if such systems can be used by individuals with limited training and/or by remote deployment of monitoring devices. Many techniques have already been developed for such detection applications, yet most of them suffer from slow color development, high detection limits (i.e. relative insensitivity to the target nutrients), the use of highly toxic reagents, and/or poor selectivity for nitrate over the more commonly occurring nitrite ion. Thus, new and improved detection systems are sorely needed. Reported herein is the development of a paper-based device employing a supramolecular, cyclodextrin-based, colorimetric detection system for nitrate, along with a dual nitrate/nitrite detection system using variations of the commonly used Griess reagents. The colorimetric responses of the systems were analyzed and quantified via ImageJ software, allowing for more precise analysis than naked-eye detection permits.

Highly sensitive, colorimetric, paper-based devices for the detection of nitrate in marine ocean environments

256th National Meeting (2018)

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