The present work presents the systematic study of Nile Blue A (NB) dye, a cationic textile dye, through electronic and vibrational spectroscopies (Raman, resonant Raman scatter and infrared absorption) in the presence of distinct anions (chloride, bromide, perchlorate and sulfate) and protic and aprotic solvents of different polarities (water, ethanol, acetone, acetonitrile, chloroform and ethyl acetate). There were vibrational changes resulting from the formation and destruction of aggregates according to the chemical environment, besides the formation of a molecular conformation with higher energy in apolar aprotic solvents.
This paper reports the use of Raman and infrared techniques for the qualitative and quantitative analysis of plasticizers in polyvinylchloride (PVC) commercial films. FT-Raman marker bands were indentified for di-2-ethyl-hexyl adipate (DEHA) and di-2-ethyl-hexyl phthalate (DEHP), allowing for the rapid identification of these species in the commercial film. Quantitative analysis by FT-IR resulted in plasticizers concentrations ranging from 11 to 27% (w/w). Considering the little sample preparation and the low cost of the techniques, FT-IR and FT-Raman are viable techniques for a first assessment of plasticizers in commercial samples.