Abstract: A colorimetric dry-reagent test strip for direct detection of the presence of hydrogen peroxide in strongly acidic solutions without the necessity of a pH neutralization step comprises a chromogen responsive to hydrogen peroxide, an enzyme peroxidase catalyst and at least one complexing agent chosen to protect an active site of the catalyst for an amount of time sufficient to allow for the catalytic oxidation of the chromogen. The test strip has particular value in the determination of peroxide-based explosive compounds, such as hexamethylene triperoxide diamine (HMTD) or triacetone triperoxide (TATP), which require a treatment with a strong organic acid to release the hydrogen peroxide to be detected, and typically requires neutralization of the acid before a conventional test strip can be employed. The invention dispenses with the need for such a neutralization step.

Abstract: A colorimetric dry-reagent test strip for direct detection of the presence of hydrogen peroxide in strongly acidic solutions without the necessity of a pH neutralization step comprises a chromogen responsive to hydrogen peroxide, an enzyme peroxidase catalyst and at least one complexing agent. A solution of the components may be applied to a suitable carrier and allowed to dry. The resulting dry test strip is placed in contact with a solution to be tested. The test strip has particular value in the determination of peroxide-based explosive compounds, such as hexamethylene triperoxide diamine (HMTD) or triacetone triperoxide (TATP), which require a treatment with a strong organic acid to release the hydrogen peroxide to be detected, and typically requires neutralization of the acid before a conventional test strip can be employed. The invention dispenses with the need for such a neutralization step.

Abstract: An apparatus and a method for the colorimetric detection testing of peroxide-based compositions is disclosed. The apparatus comprises a first carrier having an acidic compound in dry form for hydrolysis of peroxide-based compounds and a second carrier having a colorimetric detection reagent composition in dry form. The carriers are positioned with respect to a support member to facilitate transfer of a solution containing a peroxide-based compound hydrolyzed by the acidic compound when activated into contact with the reagent composition of the second carrier for observation of any resulting color indication. The method comprises steps of applying the acidic compound and colorimetric detection reagent composition is liquid forms to the respective carriers and allowing the applied formulations to dry.

Abstract: An apparatus and a method for the colorimetric detection testing of peroxide-based compositions is disclosed. The apparatus comprises a first carrier having an acidic compound in dry form for hydrolysis of peroxide-based compounds and a second carrier having a colorimetric detection reagent composition in dry form. The carriers are positioned with respect to a support member to facilitate transfer of a solution containing a peroxide-based compound hydrolyzed by the acidic compound when activated into contact with the reagent composition of the second carrier for observation of any resulting color indication. The method comprises steps of applying the acidic compound and colorimetric detection reagent composition is liquid forms to the respective carriers and allowing the applied formulations to dry.

Abstract: A test strip construction includes a test strip having a testing region bearing a chromogenic reagent to detect the presence of a substance in a fluid test sample. A supporting member is attached to one end of the test strip in a manner such that the testing region is remote form the attachment point and is free from any contact with supporting member. When dipped into the test sample the test strip can flutter away from the supporting member to allow for full contact between that the testing region and the test sample. When removed from the test sample the supporting member provides a consistent background for observation of color changes of the reagent.

Abstract: A test strip construction includes a test strip having a testing region bearing a chromogenic reagent to detect the presence of a substance in a fluid test sample. A supporting member is attached to one end of the test strip in a manner such that the testing region is remote form the attachment point and is free from any contact with supporting member. When dipped into the test sample the test strip can flutter away from the supporting member to allow for full contact between that the testing region and the test sample. When removed from the test sample the supporting member provides a consistent background for observation of color changes of the reagent.

Abstract: A one-step integral analysis unit for the direct analysis of ammonia, wherein all necessary reagents are located in a single reagent pad comprising an indicator layer and an absorbent layer. The indicator comprises an ammonia indicator embedded in a continuous phase of a hydrophobic polymer so that gaseous ammonia, but not aqueous solutions, can penetrate the embedding polymer and reach the indicator. The second absorbent layer is buffered with hydroxide to maintain the equilibrium concentration level of ammonia to obtain best test color change results. The absorbent layer is attached to a plastic carrier and the indicator layer is attached to the absorption layer.