The Gas Chromatography/Infrared Interface: Past, Present, and Future

Gas Chromatography—Fourier Transform Infrared Spectroscopy for Unambiguous Determination of Illicit Drugs: A Proof of Concept

“…First attempts to interface a gas chromatograph to IR spectroscopy date back to four decades ago (Griffiths et al, 2008); however the real milestone came in the late 1960s, with the replacement of conventional gratings or dispersive elements with interferometers and FT mathematics (Low and Freeman, 1967). Though exploiting the clear advantage of speed of analysis, yet those hyphenated instruments used high-capacity GC columns and were operated in the stopped-flow mode (Low, 1971;Shaps and Varano, 1977).…”

Surface-Enhanced Vibrational Spectroscopy of Adsorbates on Microemulsion Synthesized Gold Nanoparticles

“…For example, colloids of varying particle size and morphology have served as templates of controlled structures for SEIRA 10 and SERS 11,12 substrates. Other techniques that have been employed to prepare metal nanoparticles and nanofilms as substrates for SEIRA and/or SERS include the use of PVD, 13,14 solution-gelation (solgel), 15 electron-beam lithography, 16,17 electrochemical deposition, 18 electrochemical roughening, 19 and galvanic displacement. 20,21 It was shown that when substrates are fabricated by galvanic displacement, the conditions necessary for optimal SEIRA enhancement are usually not necessarily the best for SERS and vice versa.…”

“…20,21 It was shown that when substrates are fabricated by galvanic displacement, the conditions necessary for optimal SEIRA enhancement are usually not necessarily the best for SERS and vice versa. 13,21 Griffiths et al reported that substrates prepared by galvanic displacement give enhancement factors for SERS that are up to ten times greater than those found for substrates on which the corresponding NPs were formed by vapor deposition. 13 There are, however, no reports of any method by which SERS or SEIRA substrates have been successful in the fabrication and characterization of monodisperse metal nanoparticles with diameters of less than 10 nm using the microemulsion method for synthesis.…”

“…13,21 Griffiths et al reported that substrates prepared by galvanic displacement give enhancement factors for SERS that are up to ten times greater than those found for substrates on which the corresponding NPs were formed by vapor deposition. 13 There are, however, no reports of any method by which SERS or SEIRA substrates have been successful in the fabrication and characterization of monodisperse metal nanoparticles with diameters of less than 10 nm using the microemulsion method for synthesis. In this paper, we report the measurement of IR and Raman spectra of adsorbates on AuNPs of particles with sizes as small as 2 to 6 nm using reverse micelles as templates for controlling the size of the AuNPs.…”

Broadband Laser-Based Infrared Detector for Gas Chromatography

“…The sample gas volume in GCs is typically in the microliter range, approximated as a volume equal to the full width at half-height (FWHH) of peaks emerging from a common capillary column. It is impossible to have a sufficient absorption path length with incoherent light sources in these small gas volumes. , The detection sensitivity of an optical absorption-based detector depends linearly on the optical path length according to the Beer–Lambert law. Typical FTIR detectors, which have been developed for coupling to GC, employ lightpipe absorption cells that are about 10 cm long and 100 μL in volume, which is insufficient for a good detection sensitivity. , Vacuum ultraviolet (VUV) detectors have recently improved the detection performance of lightpipes by utilizing the electronic transitions in the VUV that are much stronger than the vibrational ones in the infrared region.…”