BaF2 windows in FTIR

BaF2 windows are used in FTIR spectroscopy of cartilage and bone tissues. FTIR spectroscopy provides information about biochemical
composition of the tissues. BaF2 is IR transparent; and tissue sections are sliced onto these windows.

W-BF-12.7-2	BaF2 window, ø 12.7 mm x 2.0 mm	$62.00
W-BF-15-4	BaF2 window, ø 15.0 mm x 4.0 mm	$39.00
W-BF-25.4-6	BaF2 window, ø 25.4 mm x 6.0 mm	$136.00
W-BF-4-0.5	BaF2 window, ø 4" x 0.5", polished, uncoated	$1,200.00
W-BF-8-1.2	BaF2 window, ø 8.0 mm x 1.2 mm	$52.00

Examples of FTIR spectroscopy publications where BaF2 windows are used:

Candida antarctica lipase B catalyzed polymerization of lactones: Effects of immobilization matrices on polymerization kinetics & molecular weight
Industrial Biotechnology, Jun 2005, Vol. 1, No. 2 : 126 -134

Takahiko Nakaoki
NSF Center for Biocatalysis & Bioprocessing of Macromolecules, Polytechnic University, Department of Chemistry and Chemical Engineering, Six Metrotech Center, Brooklyn, New York 11201, USA.
Ying Mei
NSF Center for Biocatalysis & Bioprocessing of Macromolecules, Polytechnic University, Department of Chemistry and Chemical Engineering, Six Metrotech Center, Brooklyn, New York 11201, USA.
Lisa M. Miller
National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973. USA.
Ajay Kumar
NSF Center for Biocatalysis & Bioprocessing of Macromolecules, Polytechnic University, Department of Chemistry and Chemical Engineering, Six Metrotech Center, Brooklyn, New York 11201, USA.
Bhanu Kalra
NSF Center for Biocatalysis & Bioprocessing of Macromolecules, Polytechnic University, Department of Chemistry and Chemical Engineering, Six Metrotech Center, Brooklyn, New York 11201, USA.
M. Elizabeth Miller
Rohm and Haas Company, PO Box 904, Spring House, Pennsylvania19477, USA.
Ole Kirk
Research & Development, Novozymes A/S, Krogshoejvej 36, DK-2880 Bagsvaerd, Denmark.
Morten Christensen
Research & Development, Novozymes A/S, Krogshoejvej 36, DK-2880 Bagsvaerd, Denmark.
Richard A. Gross
NSF Center for Biocatalysis & Bioprocessing of Macromolecules, Polytechnic University, Department of Chemistry and Chemical Engineering, Six Metrotech Center, Brooklyn, New York 11201, USA.

This study investigated the effect of enzyme immobilization on its activity for the ring-opening polymerizations of lactones with differing ring sizes. Candida antarctica lipase B (CALB) was immobilized on a wide array of support materials that varied in polymer composition, relative hydrophobicity, pore diameter, and surface area. The reaction rates and polymer molecular weights were monitored by in situ NMR measurements. Synchrotron infrared microspectroscopy (SIRMS) was used to study the enzyme distribution and secondary structure within the support matrix. The fastest reaction rates resulted by immobilization of CALB on the macroporous matrices QDM 2-3-4 and Accurel. Both of these are constructed from polypropylene and had CALB distributed throughout the matrix particles. Immobilized CALB on QDM 2-3-4 gave ε-caprolactone (ε-CL) conversion that reached 50 and 95% in 12 and 60 min, respectively. In comparison, by using CALB immobilized on Deloxan HAP, a 50% CL conversion required 120 h. Other changes that were found by immobilization of CALB on different matrices are shifts in CALB selectivity and the frequency of step-condensation reactions at monomer conversions >50%. By changing the immobilization matrix, PCL molecular weight was increased from 5,000 to 15,000. All of the CALB-matrix systems investigated in this study gave polymerizations with ε-CL conversions that followed a first-order rate law. Changes in CALB catalytic activity and specificity imply variations in CALB conformation induced by the different surfaces. However, these conformational changes must be subtle since they were not found by synchrotron IR Microspectroscopy. Two common features observed that led to CALB-matrix systems with higher activity for polyester synthesis are: i) increased density of CALB molecules within the pores of matrices, and ii) distribution of CALB throughout the matrix.