Generic Assay of Sulfur-Containing Compounds Based on Kinetics Inhibition of Gold Nanoparticle Photochemical Growth

摘要： This work describes a new, equipment-free, generic method for the determination of sulfur-containing compounds that is based on their ability to slow down the photoreduction kinetics of gold ions to gold nanoparticles. The method involves tracking the time required for a red coloration to appear in the tested sample, indicative of the formation of gold nanoparticles, and compare the measured time relative to a control sample in the absence of the target analyte. The method is applicable with minimal and simple steps requiring only two solutions (i.e., a bu?er and a gold solution), a source of light (UV or visible), and a timer. The method responds to a large variety of sulfur-containing compounds including thiols, thioesters, disul?des, thiophosphates, metal?sulfur bonds, and inorganic sulfur and was therefore such as applied to the determination of a variety of compounds dithiocarbamate and organophosphorous pesticides, biothiols, pharmaceutically active compounds, and sul?des in di?erent samples such as natural waters and wastewater, biological ?uids, and prescription drugs. The analytical ?gures of merit of the method include satisfactory sensitivity (quantitation limits at the low μM levels), good recoveries (from 93 to 109%), and satisfactory reproducibility (from 4.8 to 9.8%). The method is easily adoptable to both laboratory settings and nonlaboratory conditions for quantitative and semiquantitative analysis, respectively, is user-friendly even for the minimally trained user, and can be performed with limited resources at low cost.