PMID- 29019249
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20191120
IS  - 1520-6882 (Electronic)
IS  - 0003-2700 (Linking)
VI  - 89
IP  - 21
DP  - 2017 Nov 7
TI  - Electrochemical ATR-SEIRAS Using Low-Cost, Micromachined Si Wafers.
PG  - 11818-11824
LID - 10.1021/acs.analchem.7b03509 [doi]
AB  - Thin, micromachined Si wafers, designed as internal reflection elements (IREs) 
      for attenuated total reflectance infrared spectroscopy, are adapted to serve as 
      substrates for electrochemical ATR surface enhanced infrared absorption 
      spectroscopy (ATR-SEIRAS). The 500 mum thick wafer IREs with groove angles of 35 degrees  
      are significantly more transparent at long mid-IR wavelengths as compared to 
      conventional large Si hemisphere IREs. The appeal of greater transparency is 
      mitigated by smaller optical throughput at larger grazing angles and steeper 
      angles of incidence at the reflecting plane that reduce the enhancement factor. 
      Through use of the potential dependent adsorption of 4-methoxypyridine (MOP) as a 
      test system, the microgroove IRE is shown to provide relatively strong 
      electrochemical ATR-SEIRAS responses when the angle of incident radiation is 
      between 50 and 55 degrees , corresponding to refracted angles through the crystal of 
       approximately 40 degrees . The higher than expected enhancement is attributed to attenuation of the 
      reflection loss of p-polarized light and multiple reflections within the 
      wafer-based IRE. The micromachined IREs are shown to outperform a 25 mm radius 
      hemisphere in terms of S/N at wavenumbers less than ca. 1400 cm(-1) despite the 
      weaker signal enhancement derived from the steeper angle incident on the 
      IRE/sample interface. The high optical transparency of the new IREs allows the 
      spectral observation of displaced water libration bands at ca. 730 cm(-1) upon 
      solvent replacement by adsorbed MOP. The results are highly encouraging for the 
      further development of low-cost, Si wafer-based IREs for electrochemical 
      ATR-SEIRAS applications.
FAU - Morhart, Tyler A
AU  - Morhart TA
AD  - Department of Chemistry, University of Saskatchewan , Saskatoon, Saskatchewan S7N 
      5C9, Canada.
FAU - Unni, Bipinlal
AU  - Unni B
AD  - Department of Chemistry, University of Saskatchewan , Saskatoon, Saskatchewan S7N 
      5C9, Canada.
FAU - Lardner, Michael J
AU  - Lardner MJ
AD  - Department of Chemistry, University of Saskatchewan , Saskatoon, Saskatchewan S7N 
      5C9, Canada.
FAU - Burgess, Ian J
AU  - Burgess IJ
AUID- ORCID: 0000-0001-9611-1431
AD  - Department of Chemistry, University of Saskatchewan , Saskatoon, Saskatchewan S7N 
      5C9, Canada.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20171025
PL  - United States
TA  - Anal Chem
JT  - Analytical chemistry
JID - 0370536
EDAT- 2017/10/12 06:00
MHDA- 2017/10/12 06:01
CRDT- 2017/10/12 06:00
PHST- 2017/10/12 06:00 [pubmed]
PHST- 2017/10/12 06:01 [medline]
PHST- 2017/10/12 06:00 [entrez]
AID - 10.1021/acs.analchem.7b03509 [doi]
PST - ppublish
SO  - Anal Chem. 2017 Nov 7;89(21):11818-11824. doi: 10.1021/acs.analchem.7b03509. Epub 
      2017 Oct 25.