| 摘要 |
An indicator that is an adhesive label-like testing indicator that is used to detect the presence of trace chemical residues, e.g., explosive compound residues or other hazardous chemicals. The indicator comprises a substrate, preferably transparent, having an upper surface and a lower surface and a first portion and a second portion joined at a fold line, the first portion being smaller in area than the second portion. A pressure sensitive adhesive coats the upper surface of at least the second portion of the substrate. A first reactant is adhered to the upper surface of the first portion of the substrate. When the upper surface of the second portion, is contacted with a surface containing the trace chemical residues, e.g., the handle of a briefcase, the chemical residue adheres to the adhesive. When the first portion is subsequently folded along the fold line so that the upper surfaces of the substrate contact each other, a portion of the adhesive on the second portion remains exposed. This exposed portion may be used to attach the indicator to an article, e.g., a passport or the article tested. Subsequently, over a period of time, the first reactant and any chemical residue present react with each other to provide a color indicia indicating the presence of the chemical residue.
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