Reagent, method and kit for the detection of nitro aliphatic compounds
Inventors
Assignees
Publication Number
US-9417226-B2
Publication Date
2016-08-16
Expiration Date
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Abstract
A method for the detection of explosives using a single sample. The explosives include nitro aliphatic and nitro aromatic-based explosives. The method includes steps which require different pHs to discriminate between these types of explosives and at least in the detection step of the nitro aliphatic explosive requires the presence of a nitro aromatic compound. A kit for detecting explosives which includes a medium for collecting a sample, a base optionally impregnated on the medium; and a nitro aromatic solution for detecting a nitro aliphatic explosive by contacting the solution with the sample on the medium. A reagent including a nitro aromatic compound, having one or more additional electron withdrawing groups, in the presence of a basic compound usable for detecting nitro aliphatic explosives.
Core Innovation
The invention provides a method for the detection of explosives using a single sample, wherein the explosives include nitro aliphatic and nitro aromatic-based explosives, and the method includes steps which require different pHs to discriminate between these types of explosives and at least in the detection step of the nitro aliphatic explosive requires the presence of a nitro aromatic compound. A kit for detecting explosives is provided which includes a medium for collecting a sample, a base optionally impregnated on the medium; and a nitro aromatic solution for detecting a nitro aliphatic explosive by contacting the solution with the sample on the medium. A reagent is provided including a nitro aromatic compound, having one or more additional electron withdrawing groups, in the presence of a basic compound usable for detecting nitro aliphatic explosives.
The background identifies the growing use of home-made, improvised explosives including nitro aliphatic-based explosives such as nitro methane, nitro ethane, and nitro propane, which are readily available in the market and easily converted to form an explosive mixture. Existing methods and test kits were described for detecting nitro aromatics and other explosive classes, but those references do not describe detection of nitro aliphatic-based explosives. It is an object of the present invention to enable the detection of explosive substances containing inter alia nitro aliphatic, nitro aromatic, organic peroxide, chlorate and/or bromate containing compounds.
The invention provides for sequential detection on the same sample of nitro aliphatic, nitro aromatic, nitro amine, nitro ester, inorganic nitrate, chlorate, bromate and peroxide compounds by applying reagents in sequence to a single collection medium. The method includes contacting a sample on a collection medium with a nitro aromatic compound in a basic environment with a pH lower then the pH at which the Meisenheimer complex of the nitro aromatic compound is formed so as to detect nitro aliphatic compounds and, if no color change occurs, contacting the same sample with a basic compound with a pH higher than [procedural detail omitted for safety] to detect nitro aromatic compounds. Further sequential steps described include applying a Griess reagent to detect nitro ester and nitro amine explosive substances, contacting the same sample with a reducing metal powder suspension to indicate nitrates, applying an aromatic amine in a strongly acidic solution to detect chlorates or bromates, and contacting the same sample with a solution of transition metal cations to indicate peroxides; [procedural detail omitted for safety].
Claims Coverage
The patent includes two primary independent claims covering a sequential detection method using a single sample and a kit for colorimetric detection of explosives.
Method for detection using a single sample
Providing a sample on a collection medium; contacting the sample with a nitro aromatic compound in a basic environment with a pH lower then the pH at which the Meisenheimer complex of the nitro aromatic compound is formed so as to detect the presence of a suspect nitro aliphatic explosive compound; if a color change occurs, comparing the color produced to a color chart to ascertain whether a nitro aliphatic explosive is present; if no color change has occurred, contacting the same sample with a basic compound so as to detect the presence of a suspect nitro aromatic explosive compound where said basic compound has a pH higher than [procedural detail omitted for safety]; and if a color change occurs, comparing the color produced to a color chart to ascertain whether a nitro aromatic explosive is present.
Kit for colorimetric detection of explosives
A kit comprising a collection medium for collecting a sample of the suspect substance; a reagent which is a solution of a nitro aromatic compound for detecting a nitro aliphatic explosive substance by contacting the nitro aromatic solution with a sample collected on the collection medium; and a basic compound.
The independent claims primarily cover a pH-dependent, sequential colorimetric detection method applied to a single sample and a kit containing a collection medium, a nitro aromatic reagent for nitro aliphatic detection, and a basic compound.
Stated Advantages
Enables detection of explosive substances containing nitro aliphatic compounds as well as nitro aromatic, organic peroxide, chlorate and bromate compounds.
Allows sequential detection of multiple explosive classes using the same single sample.
Provides reduced false positives by operating at lower basic pHs below those that form Meisenheimer complexes.
Enhances color intensity and stability of the nitro aromatic detecting reagent when dissolved in non-aqueous solvents such as DMSO or acetone.
Reduces the possibility of corrosion associated with strongly basic environments by enabling detection at lower pHs.
Documented Applications
Detection of explosive substances containing nitro aliphatic compounds, including nitro methane, nitro ethane and nitro propane.
Sequential detection on a single sample of nitro aliphatic, nitro aromatic, nitro amine, nitro ester and inorganic nitrate compounds.
Sequential detection on a single sample of chlorates, bromates and organic peroxides using an acidified aromatic amine reagent and transition metal cation solutions.
Use of a kit for colorimetric detection of explosives with a collection medium that can sample a substance, a surface of an inanimate object, or an exterior of a human.
Provision of reagents in non-aqueous water-miscible solvents and bases optionally impregnated on a collection medium for field-oriented colorimetric testing.
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