Molecularly imprinted colloidal array for the high-throughput screening of explosives

The on-site and high-throughput screening of explosives has become increasingly significant in counter-terrorism and national security. We propose a simple and low-cost method for the screening of several explosives assisted by molecularly imprinted colloidal arrays within the 24-well plate. The infiltration and incorporation of various explosives in the interstitials of imprinted colloidal photonic crystals (CPC) result in red-shift and amplitude reduction of optical stop bands of the CPC. A certain linear relationship between the concentration of explosives and Bragg's diffraction shifts has been observed for a variety of explosives involving 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20, 8.5 × 10⁻⁵ M), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX, 1.02 × 10⁻⁴ M), 2,4,6-trinitrotoluene (TNT, 2.68 × 10⁻⁴ M), 2,4-dinitrotoluene (2,4-DNT, 8.9 × 10⁻⁵ M), 2,6-dinitrotoluene (2,6-DNT, 2.38 × 10⁻⁴ M), and 1,3,5-trinitrobenzene (TNB, 1.84 × 10⁻⁴ M) respectively. Significantly, color analysis, pattern recognition, and principal component analysis (PCA) were utilized to discriminate the different explosives. The proposed method was successfully applied to the high-throughput screening of synthetic explosive solutions.