While the pure silver sol has an absorption max. at 390 nm, the addition of phenylmercaptotetrazole (PMT) or mercaptobenzothiazole (MBT) to silver sol caused the color of the sol to turn orange, a new absorption peak appeared at 510-550 nm. The adsorption of halide ions competes with PMT and MBT. However, halide ions have shown a completely different influence on the spectral absorption of silver sol as compared to PMT and MBT. The different effects between PMT/MBT and halide ions due to adsorbed on silver surface on the spectral absorption resulted from the different interaction between silver and adsorbates.

Key words: ABSORPTION SPECTROMETRY, SILVER, MERCAPTO GROUP, TETRAZOLE P, SOL, BENZOTHIAZOLE, HALOGEN, SURFACES ADSORPTION