The mechanism of the dissolution, spray and deposition technique--a novel infrared sampling method

The dissolution, spray and deposition (DSD) technique, a novel infrared (IR) sampling technique, gives very sharp spectra for amino acids and peptides. The mechanism of this unique technique has been established by scanning electron microscopy (SEM) studies and found to be due to the formation of several layers of fairly large KBr crystals in situ on an IR transparent window. The zwitterions of the amino acids and dipeptides are adsorbed on the surface of these large KBr crystals, which ensures the isolation of monomers of the amino acid or dipeptide zwitterions in the KBr matrix, thereby leading to sharp and well-resolved IR spectra. This methodology provides a powerful IR sampling technique, akin to matrix isolation, with the added advantage of being extremely cost effective as it does not require low-temperatures or a sophisticated experimental set up.