Detection of explosive residues in soil and postblast debris is an important issue in sensor design for environmental and criminological purposes. An easy-to-use and low-cost gold nanoparticle (AuNP)-based colorimetric sensor was developed for the determination of nitroaromatic explosives, i.e., trinitrotoluene (TNT) and tetryl, capable of analyte detection at picomolar (pM) levels. The sensor nanoparticles were synthesized by functionalizing the negatively charged thioglycolic acid (TGA)-modified AuNPs with positively charged (±)- trans-1,2-diaminocyclohexane (DACH) at a carefully calculated pH. The working principle of the sensor is charge-transfer (CT) interaction between the electron-rich free amino (-NH2) group of DACH and the electron-deficient -NO2 groups of TNT/tetryl, added to possible nanoparticle agglomerization via electrostatic interaction of TNT-Meisenheimer anions with more than one cationic DACH-modified AuNP. The limit of detection (LOD) and limit of quantification (LOQ) of the sensor were 1.76 pM and 5.87 pM for TNT and 1.74 pM and 5.80 pM for tetryl, respectively. TNT, tetryl, and tetrytol, extracted from a nitroaromatic explosive-contaminated soil sample, were determined with the proposed sensor, yielding good recoveries. The sensor could be selectively applied to various mixtures of TNT with common energetic materials such as RDX, HMX, and PETN. Additionally, common soil ions (Cl-, NO3-, SO42-, K+, Mg2+, Ca2+, Cu2+, Fe2+, Fe3+, and Al3+) as well as detergents, sugar, sweeteners, acetylsalicylic acid (aspirin), caffeine, and paracetamol-based painkiller drugs, which may be used as camouflage materials for explosives, either had no adverse effects or removable interferences on the detection method. The developed method was statistically validated against a GC-MS literature method.

We propose in this work a general and versatile methodology for electrochemical monitoring of persistent pharmaceutical micropollutants. The system presented is based on an electroactive and electropolymerized hapten (mimetic molecule of the pollutant to be detected) and a specific antibody that competitively binds either the hapten or the pollutant. The current delivered by the device depends on this competitive equilibrium and therefore on the pollutant's concentration. The determination of the pharmaceutical product operates within minutes, using square wave voltammetry without labeling or addition of a reactant in solution; the competitive hapten/antibody transduction produces a "signal-on" (a current increase). Applied to acetaminophen, this electrochemical immunosensor presents a very low detection limit of ca. 10 pM, (S/N=3) and a very high selectivity towards structural analogs (aspirin, BPA, and piperazine) even in a mixture.

The acute effects of therapeutic doses of acetylsalicylic acid (ASA) on renal water and solute output, and the possible interaction of ASA with the diuretic effects of furosemide, have been studied in a double blind double cross over study in healthy human subjects. There was a significant decrease in 24 h sodium excretion and Na/K ratio in urine in the ASA-treated subjects. The effect of ASA on urinary sodium excretion was most prominent during day time (8 a.m.-10 p.m.) and on days with low sodium intake, as confirmed by control sodium excretion and plasma renin activity. A decrease in urine volume and an increase in tubular reabsorption of free water were caused by ASA, the antidiuretic effect being most marked at night (10 p.m.-8 a.m.). No action of ASA on the effect of furosemide on urinary sodium excretion was found. Creatinine clearance remained unaltered by ASA treatment, and ASA did not interfere with the increase in urinary creatinine excretion after furosemide treatment.