| Fiber Optic Coupled Grazing Angle/Fourier Transform Reflection Absorption Infrared Spectroscopy (FT-RAIRS) has been investigated as a potential technique to develop a new methodology for detection of explosive and pharmaceutical residues on surfaces. The methodology is remote sensed, in situ and can detect nanograms of the compounds. It is solvent free and requires no sample preparation. Smearing technique and thermal inkjet (TIJ) technology were used for transferring the target analyte on the substrates to be used as standards. The sample transfer methods gave good sample distribution, reduced sample loss on transfer and were easy to manipulate giving good reproducible distributions. Samples with surface concentrations ranging from micrograms/cm2 to nanograms/cm2 of explosives: 2,6-dinitrotuelene (DNT), 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), nitroglycerine (NG) and triacetone triperoxide (TATP) and of the active pharmaceutical ingredient (API) ibuprofen were deposited on stainless steel metal surface. Methanol, acetone, dichloromethane, tetrahydrofuran and acetonitrile were used as transfer solvents for smearing. Mixtures of Acetonitrile, methanol and 2-propanol were used for thermal inkjet mass transfers. TATP sublimation properties were analyzed at various temperatures. The data were analyzed using Chemometrics routines. In particular, Partial Least Squares (PLS) multivariate analysis was used. The results of the experiments gave intense absorption bands in the fingerprint region of the infrared spectrum that were used to quantify and calculate the detection limit for each compound. |
