A Study on the Qualitative and Quantitative Analysis of Nanogram Samples by Transmission Infrared Spectroscopy with the Use of Silver Island Films

Abstract

Qualitative and quantitative analysis of nanogram amounts of substances by transmission infrared spectroscopy with the use of silver island films was carried out. The effect of silver thickness, the comparison of several plates (Ge, BaF2, and ZnSe), the dynamic range of intensity enhancement vs. sample amount, and the enhancement stability after sample deposition were investigated extensively to determine the optimum conditions. The limits of detection (LOD) of several substances were also described. LOD values ranging from 5 ng/cm2 for polydimethylsiloxane to 10 ng/cm2 for diethylphthalate were obtained, and these values show a remarkable improvement in LOD in comparison with results from normal transmission spectroscopy. A quantitative study was also undertaken. A good linear relationship with respect to the amount of triphenyl phosphate, ranging from 25 to 250 ng/cm2, was obtained. The data were reproducible with a coefficient of variation of 15%, and this variation was comparable to that obtained with several surface-enhanced Raman scattering methods.

p‐Nitrobenzoic Acid Adsorption on Nanostructured Gold Surfaces Investigated by Combined Experimental and Computational Approaches

“…[1][2][3][4][5][6][7][8][9] It was reported for the first time in 1980, [2] and is usually connected with surfaces of copper, silver, gold, [3][4][5] and transition metals including Pt and Pt-group metals, [6,7] as opposed to neutral substrates such as calcium fluoride. The IR absorption enhancement offered by SEIRA was quickly seen as a new route for improving chemical sensors [8] and analyzing nanogram samples.…”

“…The IR absorption enhancement offered by SEIRA was quickly seen as a new route for improving chemical sensors [8] and analyzing nanogram samples. [9] Nowadays, the SEIRA effect has become a popular approach in nanoscience. The SEIRA approach was used, for example, in IR studies of nucleic acid interactions with carbon nanotubes [10] and structural peculiarities of DNA from cancer cells.…”

Surface-Enhanced Infrared Absorption

“…Enhanced spectra can be observed in the transmission [9,10], attenuatedtotal-reflection (ATR) [5,6,7], external-reflection [11], and diffuse-reflection modes [12]. In ATR and external-reflection measurements, the observed band intensities depend on the polarization and angle of incidence of the infrared radiation [11,13,14].…”

“…Therefore, SEIRAS techniques that lower the detection limit of infrared spectroscopy are of great interest. Trace amount of molecules, ranging from picograms to nanograms [9,39,40], and very thin organic and bioorganic films, including Langmuir-Blodgett films and self-assembled monolayers (SAMs) [22,41,42,43,44,45] have been analyzed. SEIRAS can also be used for chemical sensing [18,45,46,47,48].…”

Post-annealing temperature dependence of infrared absorption enhancement of polymer on evaporated silver films

“…Silver films that are evaporated onto dielectric substrates enhance infrared absorption of surface molecules [1][2][3][4][5][6][7][8][9][10][11][12]. Most investigations have concluded that physical effect of the absorption enhancement can be caused by surface electromagnetic field enhancements associated with collective electron resonance in metal islands.…”