A wipe for detecting the presence of an explosive substance is composed of an absorbent or adsorbent substrate and a chemical detection solution impregnated within the substrate. In one embodiment the chemical detection solution includes a combination of reagents operable, when contacted with a particular explosive substance to undergo a chemical reaction or a series of chemical reactions to produce a compound having a visible color. In another embodiment, the chemical detection solution includes a redox color indicating agent that is operable to exhibit a color change upon reacting with the explosive substance.

Various techniques are provided to determine the presence of trace chemicals corresponding to various materials of interest. In one example, a method includes receiving a vapor-phase nitric acid precursor. The vapor-phase nitric acid precursor is subsequently hydrolyzed in the presence of an acid catalyst to form nitric acid. The nitric acid is then received at a chemical reporter of a chemical detector. A response of the chemical reporter to the nitric acid is detected by the chemical reporter to determine whether materials of interest are present. Additional methods and related devices are also provided.

A method of measuring nitrate concentration in an aqueous sample include mixing the aqueous sample with a water-soluble thioether compound including a chromophore group in the presence of a water soluble catalyst; measuring a color change, and correlating the color change to nitrate concentration.

A method of measuring nitrate concentration in an aqueous sample includes mixing the aqueous sample with a water-soluble thioether chosen to reduce nitrate in the aqueous sample to nitrite in the presence of a water soluble catalyst, and a water soluble reagent system adapted to interact with nitrite to generate a color; measuring color generation, and correlating the color generation to nitrate concentration.

Systems, devices, kits, and methods for detecting and quantifying targeted compounds within a liquid (such as urine) are provided. Such systems, devices, and methods may be autonomous, noninvasive, and provide quick and accurate results. The systems and devices are at least partially disposable (single-use) and configured to be embedded within or applied to a conventional diaper or the like. Methods for using the systems and devices hereof include receiving a liquid to be tested within a portion of a disposable device, allowing the liquid to traverse through one or more channels defined within the device in a controlled fashion, reacting the liquid with one or more chemical reagents, using a sensing unit to collect photocurrent data regarding the chemical reach on(s), and wirelessly transmitting that data to a computing unit for storage and quantitative analysis.

Reagents and methods are disclosed for detection of oxidizers and inorganic salts and other analytes of interest. The reagents can interact with their target analytes, especially oxidizer compositions or oxidizer-based explosives, to selectively enhance their ionization yield, interacting by chemical reaction or by forming an associative adduct which facilitates their detection. For example, the reagents can adduct with the counter-ion of the intended analyte for improved direct detection and/or react chemically via acid-base reactions to produce a new product for detection. In another aspect of the invention, reactive reagents and methods are also disclosed that facilitate indirect detection of the analyte at lower temperatures based on reduction-oxidation (redox) chemistry. These reagents are particularly useful in detecting oxidizer analytes.

A system and method is provided for detection at least one of nitrite (NO2), nitric oxide (NO), nitrogen dioxide (NO2), and other nitrogen oxides (NO.sub.x) on a substrate, such as skin. According to one aspect, a diagnostic device for measuring a concentration of at least one of nitrite (NO2), nitrogen dioxide (NO2), nitric oxide (NO), and other nitrogen oxides (NO.sub.x) on a substrate comprises a patch comprising at least one chemical compound capable of reacting with the at least one of nitrite, nitrogen dioxide, nitric oxide, and other nitrogen oxides to provide an indicator.

Provided herein are improved fluorogenic compounds and probes that can be used as reagents for measuring, detecting and/or screening peroxynitrite. The fluorogenic compounds of the invention can produce fluorescence colors, such as green, yellow, red, or far-red. Also provided herein are fluorogenic compounds for selectively staining peroxynitrite in the mitochondria of living cells. Provided also herein are methods that can be used to measure, directly or indirectly, the presence and/or amount of peroxynitrite in chemical samples and biological samples such as cells and tissues in living organisms. Also provided are high-throughput screening methods for detecting or screening peroxynitrite or compounds that can increase or decrease the level of peroxynitrite in chemical and biological samples.

A compound, or a protonate or salt thereof, having a formula I of: wherein Y represents an optionally substituted aromatic group; n is 1 or 2; a is 0 to 4; R.sup.1 and R.sup.2 are each independently H; optionally substituted alkyl; optionally substituted aralkyl; acyl; phosphonyl; S0.sub.2R.sup.12; C(0)R.sup.13; C(0)OR.sup.14; C(0)NR.sup.15R.sup.16; C(0)CH.sub.2R.sup.17; or C(S)NR.sup.18R.sup.19; S(0)R20; or S0.sub.2NR.sup.21R.sup.22, wherein R.sup.12-R.sup.22 are each independently H, optionally substituted alkyl, optionally substituted aralkyl, optionally substituted aryl, or C(0)R.sup.23, wherein R.sup.23 is H, optionally substituted alkyl, optionally substituted aralkyl, or optionally substituted aryl; and each R.sup.3 is independently optionally substituted alkyl, halogen, optionally substituted alkoxy, optionally substituted carboxyl, amide; amino; or nitro.

Reagents and methods are disclosed for detection of oxidizers and inorganic salts and other analytes of interest. The reagents can interact with their target analytes, especially oxidizer compositions or oxidizer-based explosives, to selectively enhance their ionization yield, interacting by chemical reaction or by forming an associative adduct which facilitates their detection. For example, the reagents can adduct with the counter-ion of the intended analyte for improved direct detection and/or react chemically via acid-base reactions to produce a new product for detection. In another aspect of the invention, reactive reagents and methods are also disclosed that facilitate indirect detection of the analyte at lower temperatures based on reduction-oxidation (redox) chemistry. These reagents are particularly useful in detecting oxidizer analytes.