Nonbiological Inhibition-Based Sensing (NIBS) Demonstrated for the Detection of Toxic Sulfides

The purpose of this paper is to report on a new technique in chemical detection: nonbiological inhibition-based sensing (NIBS). This method uses a new approach to chemical amplification, where the analyte inhibits rather than enhances the rate of catalytic reaction. Although there are many possible catalysts for this technique, such as enzymes, this paper focuses on using the selective binding found in colorimetric detection. Colorimetric methods are selective; however, they are not particularly sensitive. Using nonbiological-based molecules allows for selective detection without the shelf-life issues that are associated with enzymes. In practice, we can use the active substances in Draeger tubes and related systems as catalysts. Analytes of interest inhibit the catalysts that leads to a large signal. The work presented here focuses on the detection of toxic sulfide compounds. Using NIBS, we observe that we can enhance the sensitivity of the system by 2 orders of magnitude with no apparent loss in selectivity. We can also decrease the detection time from 5 h to 10 min. So far, we have demonstrated the technique for sulfide detection; however, we believe that the technique can have general use in the detection of toxic compounds.