Portable combination of Fourier transform infrared spectroscopy and differential mobility spectrometry for advanced vapor phase analysis

Abstract

Designing mobile devices for the analysis of complex sample mixtures containing a variety of analytes at different concentrations across a large dynamic range remains a challenging task in many analytical scenarios. To meet this challenge, a compact hybrid analytical platform has been developed combining Fourier transform infrared spectroscopy based on substrate-integrated hollow waveguides (iHWG-FTIR) with gas chromatography coupled differential mobility spectrometry (GC-DMS). Due to the complementarity of these techniques regarding analyte type and concentration, their combination provides a promising tool for the detection of complex samples containing a broad range of molecules at different concentrations. To date, the combination of infrared spectroscopy and ion mobility techniques remains expensive and bound to a laboratory utilizing e.g. IMS as prefilter or IR as ionization source. In the present study, a cost-efficient and portable solution has been developed and characterized representing the first truly hyphenated IR-DMS system. As a model analyte mixture, 5 ppm isopropylmercaptan (IPM) in methane (CH4) were diluted, and the concentration-dependent DMS signal of IPM along with the concentration-dependent IR signal of CH4 were recorded for all three hybrid IR-DMS systems. While guiding the sample through the iHWG-FTIR or the GC-DMS first did not affect the obtained signals, optimizing the IR data acquisition parameters did benefit the analytical results.

Hybrid Analytical Platform Based on Field-Asymmetric Ion Mobility Spectrometry, Infrared Sensing, and Luminescence-Based Oxygen Sensing for Exhaled Breath Analysis

“…CO 2 concentrations were recorded via iHWG coupled FTIR spectroscopy. The setup and gas cell are described in detail elsewhere [53]. Light from an ALPHA FTIR spectrometer (Bruker Optik GmbH, Ettlingen, Germany) was coupled into an iHWG (aluminum, 7.5 cm optical path length, 4 mm × 4 mm internal cross-section, produced by fine mechanical workshop West, Ulm University, Ulm, Germany), and then onto the internal detector of the spectrometer via two gold-coated off-axis parabolic mirrors (Thorlabs, MPD254254-90-M01, 2″ RFL).…”

Analisis Molekular dan Transpor Ion Natrium Silikat

“…Jika dua buah elektroda yang terpisah dengan jarak l berada pada selisih potensial (133) (   ), maka ion dalam larutan diantara kedua elektroda tersebut akan mengalami medan listrik (E) sebesar : = ∆∅ …………………………………………………………(1) (134; 135) Untuk ion (muatan ion) mengalami gaya sebesar : = = ∆∅ …………………………………………………..(2) (135)(136)(137)(138) Kation menuju elektroda negative, dan anion menuju elektroda positif. Namun saat ion bergerak melalui pelarut maka ion akan mengalami gaya gesekan yang akan memperlambat muatannya yang sebanding dengan kecepatan (139)(140)(141)(142). Maka dapat disimpulkan gaya perlambatan ini sebagai: = = 6 ………………………………..(3) (143) Kedua gaya ini bekerja dalam arah yang berlawanan dan ion mencapai kecepatan akhir, yaitu kecepatan hanyut ion (s), jika gaya mempercepat F diimbangi oleh gaya perlambatan F (139; 141; 143-145)'.…”

Combination of FTIR Spectroscopy and Chemometric Method on Quantitative Approach - A Review

“…MIR region is mainly utilized for numerous applications by employing IR spectroscopy, however, NIR and farinfrared regions were too offer significant data concerning materials [8]. In MIR spectroscopy, absorption of photons takes place and molecular vibrations get excited in the spectral regime of 2-20 µm which results in achieving an unambiguous absorption pattern that may aid as molecular fingerprints for the detection and quantification of analytes [9]. Chemical and biochemical reactions can be identified by this technique from IR spectrum on the basis of appearance or disappearance of specific band of functional group or by observing the shift in band if structure involve change in structure of end product [10].…”