A low-cost yet highly sensitive colorimetric sensor array for the detection and identification of toxic industrial chemicals (TICs) has been developed. The sensor consists of a disposable array of cross-responsive nanoporous pigments whose colors are changed by diverse chemical interactions with analytes. Clear differentiation among 20 different TICs has been easily achieved at both their IDLH (immediately dangerous to life or health) concentration within 2 min of exposure and PEL (permissible exposure limit) concentration within 5 min of exposure with no errors or misclassifications. Detection limits are generally well below the PEL (in most cases below 5% of PEL) and are typically in the low ppb range. The colorimetric sensor array is not responsive to changes in humidity or temperature over a substantial range. The printed arrays show excellent batch to batch reproducibility and long shelf life (greater than 3 months).

Sensitive detection of trimethylamine both in aqueous and gaseous phases has been accomplished using an inexpensive colorimetric sensor array. Distinctive color change patterns provide facile discrimination over a wide range of concentrations for trimethylamine with >99% accuracy of classification. Calculated limits of detection are well below the diagnostically significant concentration for trimethylaminuria (fish malodor syndrome). The sensor array shows good reversibility after multiple uses and is able to cleanly discriminate trimethylamine from similar amine odorants. Portable sensing of trimethylamine vapors at ppb concentrations is described using a cell phone camera or a hand-held optoelectronic nose. Application of the sensor array in detecting mouth and skin odor as a potential tool for portable diagnosis of trimethylaminuria is also illustrated.