Abstract

In terahertz (THz) and far-infrared (FIR) spectroscopic measurements, weak absorption spectral features due to small quantities of test sample can be masked by undesirable etalon fringe artifacts caused by multiple reflections within a pellet or a rigid sample holder. A double-layered nitrocellulose (NC) membrane structure is proposed in this paper as an alternative holder for small quantities of either dry or wet pure (no added polyethylene powder) samples with significantly reduced etalon artifacts. Utilizing a THz time-domain spectroscopy system and a synchrotron source, we demonstrate the performance of the NC structure across the THz/FIR spectrum, benchmarking against pellets holding similarly small quantities of α-lactose powder either with or without different grades of polyethylene powder. With only pure samples to consider, scattering can be mitigated effectively in NC-derived spectra to reduce their baselines.

© 2015 Optical Society of America

Full Article  |  PDF Article
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References

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    [Crossref]
  3. M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by granular composite materials: An effective medium theory,” Appl. Phys. Lett. 100(1), 011107 (2012).
    [Crossref]
  4. M. W. Nicholas and K. Nelson, “North, South, or East? Blotting Techniques,” J. of Investigative Dermatology 133(7), E1–E3 (2013).
    [Crossref]
  5. M. N. Costa, B. Veigas, J. M. Jacob, D. S. Santos, J. Gomes, P. V. Baptista, R. Martins, J. Inacio, and E. Fortunato, “A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper,” Nanotechnology 25(9), 094006 (2014).
    [Crossref] [PubMed]
  6. Y. H. Tan, M. Liu, B. Nolting, J. G. Go, J. Gervay-Hague, and G. Liu, “A nanoengineering approach for investigation and regulation of protein immobilization,” ACS Nano 2(11), 2374–2384 (2008).
    [Crossref]
  7. E. R. Tovey and B. A. Baldo, “Protein binding to nitrocellulose, nylon and PVDF membranes in immunoassays and electroblotting,” J. Biochem. Biophys. Methods 19(2–3), 169–183 (1989).
    [Crossref] [PubMed]
  8. D. Grischkowsky, S. R. Keiding, M. van Exter, and C. Fattinger, “Far-infrared time-domain spectroscopy with terahertz beams of dielectrics and semiconductors,” J. Opt. Soc. Am. 7(10), 2006–2015 (1990).
    [Crossref]
  9. M. van Exter, C. Fattinger, and D. Grischkowsky, “Terahertz time-domain spectroscopy of water vapor,” Opt. Lett. 14(20), 1128–1130 (1989).
    [Crossref]
  10. X. Xin, H. Altan, A. Saint, D. Matten, and R. R. Alfano, “Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature,” J. Appl. Phys. 100(9), 094905 (2006).
    [Crossref]
  11. G. D. Dean and D. H. Martin, “Inter-molecular vibrations of crystalline polyethylene and long-chain paraffins,” Chem. Phys. Lett. 1(9), 415–416 (1967).
    [Crossref]
  12. J. W. Fleming, G. W. Chantry, P. A. Turner, E. A. Nicol, H. A. Willis, and M. E. A. Cudby, “Temperature effects and observation of B2u lattice mode in far infrared absorption spectrum of polyethylene,” Chem. Phys. Lett. 17(1), 84–85 (1972).
    [Crossref]
  13. J. R. Birch, “The far infrared optical constants of polyethylene,” Infrared Phys. 30(2), 195–197 (1990).
    [Crossref]
  14. P. F. Fox and P. L. H. McSweeney, Dairy Chemistry and Biochemistry (Blackie Academic & Professional, 1998).
  15. J. L. Crisp, S. E. Dann, M. Edgar, and C. G. Blatchford, “The effect of particle size on the dehydration/rehydration behaviour of lactose,” International J. Pharmaceutics 391(1–2), 38–47 (2010).
    [Crossref]
  16. B. T. Kurien and R. H. Scofield, “Protein blotting: A review,” J. Immunological Methods 274(1–2), 1–15 (2003).
    [Crossref]
  17. G. M. Png, R. J. Falconer, B. M. Fischer, H. A. Zakaria, S. P. Mickan, A. P. J. Middelberg, and D. Abbott, “Terahertz spectroscopic differentiation of microstructures in protein gels,” Opt. Express 17(15), 13102–13115 (2009).
    [Crossref] [PubMed]
  18. H. A. Zakaria, B. M. Fischer, A. P. Bradley, I. Jones, D. Abbott, A. P. J. Middelberg, and R. J. Falconer, “Low-frequency spectroscopic analysis of monomeric and fibrillar lysozyme,” Appl. Spectrosc. 65(3), 260–264 (2011).
    [Crossref] [PubMed]
  19. K. Shiraga, Y. Ogawa, N. Kondo, A. Irisawa, and M. Imamura, “Evaluation of the hydration state of saccharides using terahertz time-domain attenuated total reflection spectroscopy,” Food Chemistry 140(1–2), 315–320 (2013).
    [Crossref] [PubMed]
  20. Y. Listiohadi, J. A. Hourigan, R. W. Sleigh, and R. J. Steele, “Moisture sorption, compressibility and caking of lactose polymorphs,” International J. Pharmaceutics 359(1–2), 123–134 (2008).
    [Crossref]
  21. J. H. Kirk, S. E. Dann, and C. G. Blatchford, “Lactose: A definitive guide to polymorph determination,” International J. Pharmaceutics 334(1–2), 103–114 (2007).
    [Crossref]
  22. R. Lefort, V. Caron, J.-F. Willart, and M. Descamps, “Mutarotational kinetics and glass transition of lactose,” Solid State Communications 140(7–8), 329–334 (2006).
    [Crossref]
  23. M. Hineno and H. Yoshinaga, “Far-infrared spectra of galactose and lactose at liquid He temperature,” Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy A29(2), 301–305 (1973).
    [Crossref]
  24. C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles, (John Wiley & Sons, 1983).
  25. H. Vromans, A. H. De Boer, G. K. Bolhuis, C. F. Lerk, K. D. Kussendrager, and H. Bosch, “Studies on tableting properties of lactose. Part 2: Consolidation and compaction of different types of crystalline lactose,” Pharmaceutisch Weekblad-Scientific Edition 7(5), 186–193 (1985).
    [Crossref] [PubMed]
  26. V. Busignies, P. Tchoreloff, B. Leclerc, M. Besnard, and G. Couarraze, “Compaction of crystallographic forms of pharmaceutical granular lactoses. I. Compressibility,” Eur. J. Pharm. Biopharm. 58(3), 569–576 (2004).
    [Crossref] [PubMed]
  27. M. Franz, B. M. Fischer, and M. Walther, “The Christiansen effect in terahertz time-domain spectra of coarse-grained powders,” Appl. Phys. Lett. 92(2), 021107 (2008).
    [Crossref]

2014 (1)

M. N. Costa, B. Veigas, J. M. Jacob, D. S. Santos, J. Gomes, P. V. Baptista, R. Martins, J. Inacio, and E. Fortunato, “A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper,” Nanotechnology 25(9), 094006 (2014).
[Crossref] [PubMed]

2013 (2)

M. W. Nicholas and K. Nelson, “North, South, or East? Blotting Techniques,” J. of Investigative Dermatology 133(7), E1–E3 (2013).
[Crossref]

K. Shiraga, Y. Ogawa, N. Kondo, A. Irisawa, and M. Imamura, “Evaluation of the hydration state of saccharides using terahertz time-domain attenuated total reflection spectroscopy,” Food Chemistry 140(1–2), 315–320 (2013).
[Crossref] [PubMed]

2012 (2)

M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by two phased media with optically soft scatterers,” J. of Appl. Phys. 112(11), 113112 (2012).
[Crossref]

M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by granular composite materials: An effective medium theory,” Appl. Phys. Lett. 100(1), 011107 (2012).
[Crossref]

2011 (1)

2010 (1)

J. L. Crisp, S. E. Dann, M. Edgar, and C. G. Blatchford, “The effect of particle size on the dehydration/rehydration behaviour of lactose,” International J. Pharmaceutics 391(1–2), 38–47 (2010).
[Crossref]

2009 (1)

2008 (3)

M. Franz, B. M. Fischer, and M. Walther, “The Christiansen effect in terahertz time-domain spectra of coarse-grained powders,” Appl. Phys. Lett. 92(2), 021107 (2008).
[Crossref]

Y. Listiohadi, J. A. Hourigan, R. W. Sleigh, and R. J. Steele, “Moisture sorption, compressibility and caking of lactose polymorphs,” International J. Pharmaceutics 359(1–2), 123–134 (2008).
[Crossref]

Y. H. Tan, M. Liu, B. Nolting, J. G. Go, J. Gervay-Hague, and G. Liu, “A nanoengineering approach for investigation and regulation of protein immobilization,” ACS Nano 2(11), 2374–2384 (2008).
[Crossref]

2007 (1)

J. H. Kirk, S. E. Dann, and C. G. Blatchford, “Lactose: A definitive guide to polymorph determination,” International J. Pharmaceutics 334(1–2), 103–114 (2007).
[Crossref]

2006 (2)

R. Lefort, V. Caron, J.-F. Willart, and M. Descamps, “Mutarotational kinetics and glass transition of lactose,” Solid State Communications 140(7–8), 329–334 (2006).
[Crossref]

X. Xin, H. Altan, A. Saint, D. Matten, and R. R. Alfano, “Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature,” J. Appl. Phys. 100(9), 094905 (2006).
[Crossref]

2004 (1)

V. Busignies, P. Tchoreloff, B. Leclerc, M. Besnard, and G. Couarraze, “Compaction of crystallographic forms of pharmaceutical granular lactoses. I. Compressibility,” Eur. J. Pharm. Biopharm. 58(3), 569–576 (2004).
[Crossref] [PubMed]

2003 (1)

B. T. Kurien and R. H. Scofield, “Protein blotting: A review,” J. Immunological Methods 274(1–2), 1–15 (2003).
[Crossref]

2001 (1)

1990 (2)

J. R. Birch, “The far infrared optical constants of polyethylene,” Infrared Phys. 30(2), 195–197 (1990).
[Crossref]

D. Grischkowsky, S. R. Keiding, M. van Exter, and C. Fattinger, “Far-infrared time-domain spectroscopy with terahertz beams of dielectrics and semiconductors,” J. Opt. Soc. Am. 7(10), 2006–2015 (1990).
[Crossref]

1989 (2)

E. R. Tovey and B. A. Baldo, “Protein binding to nitrocellulose, nylon and PVDF membranes in immunoassays and electroblotting,” J. Biochem. Biophys. Methods 19(2–3), 169–183 (1989).
[Crossref] [PubMed]

M. van Exter, C. Fattinger, and D. Grischkowsky, “Terahertz time-domain spectroscopy of water vapor,” Opt. Lett. 14(20), 1128–1130 (1989).
[Crossref]

1985 (1)

H. Vromans, A. H. De Boer, G. K. Bolhuis, C. F. Lerk, K. D. Kussendrager, and H. Bosch, “Studies on tableting properties of lactose. Part 2: Consolidation and compaction of different types of crystalline lactose,” Pharmaceutisch Weekblad-Scientific Edition 7(5), 186–193 (1985).
[Crossref] [PubMed]

1973 (1)

M. Hineno and H. Yoshinaga, “Far-infrared spectra of galactose and lactose at liquid He temperature,” Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy A29(2), 301–305 (1973).
[Crossref]

1972 (1)

J. W. Fleming, G. W. Chantry, P. A. Turner, E. A. Nicol, H. A. Willis, and M. E. A. Cudby, “Temperature effects and observation of B2u lattice mode in far infrared absorption spectrum of polyethylene,” Chem. Phys. Lett. 17(1), 84–85 (1972).
[Crossref]

1967 (1)

G. D. Dean and D. H. Martin, “Inter-molecular vibrations of crystalline polyethylene and long-chain paraffins,” Chem. Phys. Lett. 1(9), 415–416 (1967).
[Crossref]

Abbott, D.

M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by two phased media with optically soft scatterers,” J. of Appl. Phys. 112(11), 113112 (2012).
[Crossref]

M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by granular composite materials: An effective medium theory,” Appl. Phys. Lett. 100(1), 011107 (2012).
[Crossref]

H. A. Zakaria, B. M. Fischer, A. P. Bradley, I. Jones, D. Abbott, A. P. J. Middelberg, and R. J. Falconer, “Low-frequency spectroscopic analysis of monomeric and fibrillar lysozyme,” Appl. Spectrosc. 65(3), 260–264 (2011).
[Crossref] [PubMed]

G. M. Png, R. J. Falconer, B. M. Fischer, H. A. Zakaria, S. P. Mickan, A. P. J. Middelberg, and D. Abbott, “Terahertz spectroscopic differentiation of microstructures in protein gels,” Opt. Express 17(15), 13102–13115 (2009).
[Crossref] [PubMed]

Alfano, R. R.

X. Xin, H. Altan, A. Saint, D. Matten, and R. R. Alfano, “Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature,” J. Appl. Phys. 100(9), 094905 (2006).
[Crossref]

Altan, H.

X. Xin, H. Altan, A. Saint, D. Matten, and R. R. Alfano, “Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature,” J. Appl. Phys. 100(9), 094905 (2006).
[Crossref]

Baldo, B. A.

E. R. Tovey and B. A. Baldo, “Protein binding to nitrocellulose, nylon and PVDF membranes in immunoassays and electroblotting,” J. Biochem. Biophys. Methods 19(2–3), 169–183 (1989).
[Crossref] [PubMed]

Baptista, P. V.

M. N. Costa, B. Veigas, J. M. Jacob, D. S. Santos, J. Gomes, P. V. Baptista, R. Martins, J. Inacio, and E. Fortunato, “A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper,” Nanotechnology 25(9), 094006 (2014).
[Crossref] [PubMed]

Baraniuk, R. G.

Besnard, M.

V. Busignies, P. Tchoreloff, B. Leclerc, M. Besnard, and G. Couarraze, “Compaction of crystallographic forms of pharmaceutical granular lactoses. I. Compressibility,” Eur. J. Pharm. Biopharm. 58(3), 569–576 (2004).
[Crossref] [PubMed]

Birch, J. R.

J. R. Birch, “The far infrared optical constants of polyethylene,” Infrared Phys. 30(2), 195–197 (1990).
[Crossref]

Blatchford, C. G.

J. L. Crisp, S. E. Dann, M. Edgar, and C. G. Blatchford, “The effect of particle size on the dehydration/rehydration behaviour of lactose,” International J. Pharmaceutics 391(1–2), 38–47 (2010).
[Crossref]

J. H. Kirk, S. E. Dann, and C. G. Blatchford, “Lactose: A definitive guide to polymorph determination,” International J. Pharmaceutics 334(1–2), 103–114 (2007).
[Crossref]

Bohren, C. F.

C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles, (John Wiley & Sons, 1983).

Bolhuis, G. K.

H. Vromans, A. H. De Boer, G. K. Bolhuis, C. F. Lerk, K. D. Kussendrager, and H. Bosch, “Studies on tableting properties of lactose. Part 2: Consolidation and compaction of different types of crystalline lactose,” Pharmaceutisch Weekblad-Scientific Edition 7(5), 186–193 (1985).
[Crossref] [PubMed]

Bosch, H.

H. Vromans, A. H. De Boer, G. K. Bolhuis, C. F. Lerk, K. D. Kussendrager, and H. Bosch, “Studies on tableting properties of lactose. Part 2: Consolidation and compaction of different types of crystalline lactose,” Pharmaceutisch Weekblad-Scientific Edition 7(5), 186–193 (1985).
[Crossref] [PubMed]

Bradley, A. P.

Busignies, V.

V. Busignies, P. Tchoreloff, B. Leclerc, M. Besnard, and G. Couarraze, “Compaction of crystallographic forms of pharmaceutical granular lactoses. I. Compressibility,” Eur. J. Pharm. Biopharm. 58(3), 569–576 (2004).
[Crossref] [PubMed]

Caron, V.

R. Lefort, V. Caron, J.-F. Willart, and M. Descamps, “Mutarotational kinetics and glass transition of lactose,” Solid State Communications 140(7–8), 329–334 (2006).
[Crossref]

Chantry, G. W.

J. W. Fleming, G. W. Chantry, P. A. Turner, E. A. Nicol, H. A. Willis, and M. E. A. Cudby, “Temperature effects and observation of B2u lattice mode in far infrared absorption spectrum of polyethylene,” Chem. Phys. Lett. 17(1), 84–85 (1972).
[Crossref]

Costa, M. N.

M. N. Costa, B. Veigas, J. M. Jacob, D. S. Santos, J. Gomes, P. V. Baptista, R. Martins, J. Inacio, and E. Fortunato, “A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper,” Nanotechnology 25(9), 094006 (2014).
[Crossref] [PubMed]

Couarraze, G.

V. Busignies, P. Tchoreloff, B. Leclerc, M. Besnard, and G. Couarraze, “Compaction of crystallographic forms of pharmaceutical granular lactoses. I. Compressibility,” Eur. J. Pharm. Biopharm. 58(3), 569–576 (2004).
[Crossref] [PubMed]

Crisp, J. L.

J. L. Crisp, S. E. Dann, M. Edgar, and C. G. Blatchford, “The effect of particle size on the dehydration/rehydration behaviour of lactose,” International J. Pharmaceutics 391(1–2), 38–47 (2010).
[Crossref]

Cudby, M. E. A.

J. W. Fleming, G. W. Chantry, P. A. Turner, E. A. Nicol, H. A. Willis, and M. E. A. Cudby, “Temperature effects and observation of B2u lattice mode in far infrared absorption spectrum of polyethylene,” Chem. Phys. Lett. 17(1), 84–85 (1972).
[Crossref]

Dann, S. E.

J. L. Crisp, S. E. Dann, M. Edgar, and C. G. Blatchford, “The effect of particle size on the dehydration/rehydration behaviour of lactose,” International J. Pharmaceutics 391(1–2), 38–47 (2010).
[Crossref]

J. H. Kirk, S. E. Dann, and C. G. Blatchford, “Lactose: A definitive guide to polymorph determination,” International J. Pharmaceutics 334(1–2), 103–114 (2007).
[Crossref]

De Boer, A. H.

H. Vromans, A. H. De Boer, G. K. Bolhuis, C. F. Lerk, K. D. Kussendrager, and H. Bosch, “Studies on tableting properties of lactose. Part 2: Consolidation and compaction of different types of crystalline lactose,” Pharmaceutisch Weekblad-Scientific Edition 7(5), 186–193 (1985).
[Crossref] [PubMed]

Dean, G. D.

G. D. Dean and D. H. Martin, “Inter-molecular vibrations of crystalline polyethylene and long-chain paraffins,” Chem. Phys. Lett. 1(9), 415–416 (1967).
[Crossref]

Descamps, M.

R. Lefort, V. Caron, J.-F. Willart, and M. Descamps, “Mutarotational kinetics and glass transition of lactose,” Solid State Communications 140(7–8), 329–334 (2006).
[Crossref]

Dorney, T. D.

Edgar, M.

J. L. Crisp, S. E. Dann, M. Edgar, and C. G. Blatchford, “The effect of particle size on the dehydration/rehydration behaviour of lactose,” International J. Pharmaceutics 391(1–2), 38–47 (2010).
[Crossref]

Falconer, R. J.

Fattinger, C.

D. Grischkowsky, S. R. Keiding, M. van Exter, and C. Fattinger, “Far-infrared time-domain spectroscopy with terahertz beams of dielectrics and semiconductors,” J. Opt. Soc. Am. 7(10), 2006–2015 (1990).
[Crossref]

M. van Exter, C. Fattinger, and D. Grischkowsky, “Terahertz time-domain spectroscopy of water vapor,” Opt. Lett. 14(20), 1128–1130 (1989).
[Crossref]

Fischer, B. M.

M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by two phased media with optically soft scatterers,” J. of Appl. Phys. 112(11), 113112 (2012).
[Crossref]

M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by granular composite materials: An effective medium theory,” Appl. Phys. Lett. 100(1), 011107 (2012).
[Crossref]

H. A. Zakaria, B. M. Fischer, A. P. Bradley, I. Jones, D. Abbott, A. P. J. Middelberg, and R. J. Falconer, “Low-frequency spectroscopic analysis of monomeric and fibrillar lysozyme,” Appl. Spectrosc. 65(3), 260–264 (2011).
[Crossref] [PubMed]

G. M. Png, R. J. Falconer, B. M. Fischer, H. A. Zakaria, S. P. Mickan, A. P. J. Middelberg, and D. Abbott, “Terahertz spectroscopic differentiation of microstructures in protein gels,” Opt. Express 17(15), 13102–13115 (2009).
[Crossref] [PubMed]

M. Franz, B. M. Fischer, and M. Walther, “The Christiansen effect in terahertz time-domain spectra of coarse-grained powders,” Appl. Phys. Lett. 92(2), 021107 (2008).
[Crossref]

Fleming, J. W.

J. W. Fleming, G. W. Chantry, P. A. Turner, E. A. Nicol, H. A. Willis, and M. E. A. Cudby, “Temperature effects and observation of B2u lattice mode in far infrared absorption spectrum of polyethylene,” Chem. Phys. Lett. 17(1), 84–85 (1972).
[Crossref]

Fortunato, E.

M. N. Costa, B. Veigas, J. M. Jacob, D. S. Santos, J. Gomes, P. V. Baptista, R. Martins, J. Inacio, and E. Fortunato, “A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper,” Nanotechnology 25(9), 094006 (2014).
[Crossref] [PubMed]

Fox, P. F.

P. F. Fox and P. L. H. McSweeney, Dairy Chemistry and Biochemistry (Blackie Academic & Professional, 1998).

Franz, M.

M. Franz, B. M. Fischer, and M. Walther, “The Christiansen effect in terahertz time-domain spectra of coarse-grained powders,” Appl. Phys. Lett. 92(2), 021107 (2008).
[Crossref]

Gervay-Hague, J.

Y. H. Tan, M. Liu, B. Nolting, J. G. Go, J. Gervay-Hague, and G. Liu, “A nanoengineering approach for investigation and regulation of protein immobilization,” ACS Nano 2(11), 2374–2384 (2008).
[Crossref]

Go, J. G.

Y. H. Tan, M. Liu, B. Nolting, J. G. Go, J. Gervay-Hague, and G. Liu, “A nanoengineering approach for investigation and regulation of protein immobilization,” ACS Nano 2(11), 2374–2384 (2008).
[Crossref]

Gomes, J.

M. N. Costa, B. Veigas, J. M. Jacob, D. S. Santos, J. Gomes, P. V. Baptista, R. Martins, J. Inacio, and E. Fortunato, “A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper,” Nanotechnology 25(9), 094006 (2014).
[Crossref] [PubMed]

Grischkowsky, D.

D. Grischkowsky, S. R. Keiding, M. van Exter, and C. Fattinger, “Far-infrared time-domain spectroscopy with terahertz beams of dielectrics and semiconductors,” J. Opt. Soc. Am. 7(10), 2006–2015 (1990).
[Crossref]

M. van Exter, C. Fattinger, and D. Grischkowsky, “Terahertz time-domain spectroscopy of water vapor,” Opt. Lett. 14(20), 1128–1130 (1989).
[Crossref]

Hineno, M.

M. Hineno and H. Yoshinaga, “Far-infrared spectra of galactose and lactose at liquid He temperature,” Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy A29(2), 301–305 (1973).
[Crossref]

Hourigan, J. A.

Y. Listiohadi, J. A. Hourigan, R. W. Sleigh, and R. J. Steele, “Moisture sorption, compressibility and caking of lactose polymorphs,” International J. Pharmaceutics 359(1–2), 123–134 (2008).
[Crossref]

Huffman, D. R.

C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles, (John Wiley & Sons, 1983).

Imamura, M.

K. Shiraga, Y. Ogawa, N. Kondo, A. Irisawa, and M. Imamura, “Evaluation of the hydration state of saccharides using terahertz time-domain attenuated total reflection spectroscopy,” Food Chemistry 140(1–2), 315–320 (2013).
[Crossref] [PubMed]

Inacio, J.

M. N. Costa, B. Veigas, J. M. Jacob, D. S. Santos, J. Gomes, P. V. Baptista, R. Martins, J. Inacio, and E. Fortunato, “A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper,” Nanotechnology 25(9), 094006 (2014).
[Crossref] [PubMed]

Irisawa, A.

K. Shiraga, Y. Ogawa, N. Kondo, A. Irisawa, and M. Imamura, “Evaluation of the hydration state of saccharides using terahertz time-domain attenuated total reflection spectroscopy,” Food Chemistry 140(1–2), 315–320 (2013).
[Crossref] [PubMed]

Jacob, J. M.

M. N. Costa, B. Veigas, J. M. Jacob, D. S. Santos, J. Gomes, P. V. Baptista, R. Martins, J. Inacio, and E. Fortunato, “A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper,” Nanotechnology 25(9), 094006 (2014).
[Crossref] [PubMed]

Jones, I.

Kaushik, M.

M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by granular composite materials: An effective medium theory,” Appl. Phys. Lett. 100(1), 011107 (2012).
[Crossref]

M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by two phased media with optically soft scatterers,” J. of Appl. Phys. 112(11), 113112 (2012).
[Crossref]

Keiding, S. R.

D. Grischkowsky, S. R. Keiding, M. van Exter, and C. Fattinger, “Far-infrared time-domain spectroscopy with terahertz beams of dielectrics and semiconductors,” J. Opt. Soc. Am. 7(10), 2006–2015 (1990).
[Crossref]

Kirk, J. H.

J. H. Kirk, S. E. Dann, and C. G. Blatchford, “Lactose: A definitive guide to polymorph determination,” International J. Pharmaceutics 334(1–2), 103–114 (2007).
[Crossref]

Kondo, N.

K. Shiraga, Y. Ogawa, N. Kondo, A. Irisawa, and M. Imamura, “Evaluation of the hydration state of saccharides using terahertz time-domain attenuated total reflection spectroscopy,” Food Chemistry 140(1–2), 315–320 (2013).
[Crossref] [PubMed]

Kurien, B. T.

B. T. Kurien and R. H. Scofield, “Protein blotting: A review,” J. Immunological Methods 274(1–2), 1–15 (2003).
[Crossref]

Kussendrager, K. D.

H. Vromans, A. H. De Boer, G. K. Bolhuis, C. F. Lerk, K. D. Kussendrager, and H. Bosch, “Studies on tableting properties of lactose. Part 2: Consolidation and compaction of different types of crystalline lactose,” Pharmaceutisch Weekblad-Scientific Edition 7(5), 186–193 (1985).
[Crossref] [PubMed]

Leclerc, B.

V. Busignies, P. Tchoreloff, B. Leclerc, M. Besnard, and G. Couarraze, “Compaction of crystallographic forms of pharmaceutical granular lactoses. I. Compressibility,” Eur. J. Pharm. Biopharm. 58(3), 569–576 (2004).
[Crossref] [PubMed]

Lefort, R.

R. Lefort, V. Caron, J.-F. Willart, and M. Descamps, “Mutarotational kinetics and glass transition of lactose,” Solid State Communications 140(7–8), 329–334 (2006).
[Crossref]

Lerk, C. F.

H. Vromans, A. H. De Boer, G. K. Bolhuis, C. F. Lerk, K. D. Kussendrager, and H. Bosch, “Studies on tableting properties of lactose. Part 2: Consolidation and compaction of different types of crystalline lactose,” Pharmaceutisch Weekblad-Scientific Edition 7(5), 186–193 (1985).
[Crossref] [PubMed]

Listiohadi, Y.

Y. Listiohadi, J. A. Hourigan, R. W. Sleigh, and R. J. Steele, “Moisture sorption, compressibility and caking of lactose polymorphs,” International J. Pharmaceutics 359(1–2), 123–134 (2008).
[Crossref]

Liu, G.

Y. H. Tan, M. Liu, B. Nolting, J. G. Go, J. Gervay-Hague, and G. Liu, “A nanoengineering approach for investigation and regulation of protein immobilization,” ACS Nano 2(11), 2374–2384 (2008).
[Crossref]

Liu, M.

Y. H. Tan, M. Liu, B. Nolting, J. G. Go, J. Gervay-Hague, and G. Liu, “A nanoengineering approach for investigation and regulation of protein immobilization,” ACS Nano 2(11), 2374–2384 (2008).
[Crossref]

Martin, D. H.

G. D. Dean and D. H. Martin, “Inter-molecular vibrations of crystalline polyethylene and long-chain paraffins,” Chem. Phys. Lett. 1(9), 415–416 (1967).
[Crossref]

Martins, R.

M. N. Costa, B. Veigas, J. M. Jacob, D. S. Santos, J. Gomes, P. V. Baptista, R. Martins, J. Inacio, and E. Fortunato, “A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper,” Nanotechnology 25(9), 094006 (2014).
[Crossref] [PubMed]

Matten, D.

X. Xin, H. Altan, A. Saint, D. Matten, and R. R. Alfano, “Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature,” J. Appl. Phys. 100(9), 094905 (2006).
[Crossref]

McSweeney, P. L. H.

P. F. Fox and P. L. H. McSweeney, Dairy Chemistry and Biochemistry (Blackie Academic & Professional, 1998).

Mickan, S. P.

Middelberg, A. P. J.

Mittleman, D. M.

Nelson, K.

M. W. Nicholas and K. Nelson, “North, South, or East? Blotting Techniques,” J. of Investigative Dermatology 133(7), E1–E3 (2013).
[Crossref]

Ng, B. W.-H.

M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by two phased media with optically soft scatterers,” J. of Appl. Phys. 112(11), 113112 (2012).
[Crossref]

M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by granular composite materials: An effective medium theory,” Appl. Phys. Lett. 100(1), 011107 (2012).
[Crossref]

Nicholas, M. W.

M. W. Nicholas and K. Nelson, “North, South, or East? Blotting Techniques,” J. of Investigative Dermatology 133(7), E1–E3 (2013).
[Crossref]

Nicol, E. A.

J. W. Fleming, G. W. Chantry, P. A. Turner, E. A. Nicol, H. A. Willis, and M. E. A. Cudby, “Temperature effects and observation of B2u lattice mode in far infrared absorption spectrum of polyethylene,” Chem. Phys. Lett. 17(1), 84–85 (1972).
[Crossref]

Nolting, B.

Y. H. Tan, M. Liu, B. Nolting, J. G. Go, J. Gervay-Hague, and G. Liu, “A nanoengineering approach for investigation and regulation of protein immobilization,” ACS Nano 2(11), 2374–2384 (2008).
[Crossref]

Ogawa, Y.

K. Shiraga, Y. Ogawa, N. Kondo, A. Irisawa, and M. Imamura, “Evaluation of the hydration state of saccharides using terahertz time-domain attenuated total reflection spectroscopy,” Food Chemistry 140(1–2), 315–320 (2013).
[Crossref] [PubMed]

Png, G. M.

Saint, A.

X. Xin, H. Altan, A. Saint, D. Matten, and R. R. Alfano, “Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature,” J. Appl. Phys. 100(9), 094905 (2006).
[Crossref]

Santos, D. S.

M. N. Costa, B. Veigas, J. M. Jacob, D. S. Santos, J. Gomes, P. V. Baptista, R. Martins, J. Inacio, and E. Fortunato, “A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper,” Nanotechnology 25(9), 094006 (2014).
[Crossref] [PubMed]

Scofield, R. H.

B. T. Kurien and R. H. Scofield, “Protein blotting: A review,” J. Immunological Methods 274(1–2), 1–15 (2003).
[Crossref]

Shiraga, K.

K. Shiraga, Y. Ogawa, N. Kondo, A. Irisawa, and M. Imamura, “Evaluation of the hydration state of saccharides using terahertz time-domain attenuated total reflection spectroscopy,” Food Chemistry 140(1–2), 315–320 (2013).
[Crossref] [PubMed]

Sleigh, R. W.

Y. Listiohadi, J. A. Hourigan, R. W. Sleigh, and R. J. Steele, “Moisture sorption, compressibility and caking of lactose polymorphs,” International J. Pharmaceutics 359(1–2), 123–134 (2008).
[Crossref]

Steele, R. J.

Y. Listiohadi, J. A. Hourigan, R. W. Sleigh, and R. J. Steele, “Moisture sorption, compressibility and caking of lactose polymorphs,” International J. Pharmaceutics 359(1–2), 123–134 (2008).
[Crossref]

Tan, Y. H.

Y. H. Tan, M. Liu, B. Nolting, J. G. Go, J. Gervay-Hague, and G. Liu, “A nanoengineering approach for investigation and regulation of protein immobilization,” ACS Nano 2(11), 2374–2384 (2008).
[Crossref]

Tchoreloff, P.

V. Busignies, P. Tchoreloff, B. Leclerc, M. Besnard, and G. Couarraze, “Compaction of crystallographic forms of pharmaceutical granular lactoses. I. Compressibility,” Eur. J. Pharm. Biopharm. 58(3), 569–576 (2004).
[Crossref] [PubMed]

Tovey, E. R.

E. R. Tovey and B. A. Baldo, “Protein binding to nitrocellulose, nylon and PVDF membranes in immunoassays and electroblotting,” J. Biochem. Biophys. Methods 19(2–3), 169–183 (1989).
[Crossref] [PubMed]

Turner, P. A.

J. W. Fleming, G. W. Chantry, P. A. Turner, E. A. Nicol, H. A. Willis, and M. E. A. Cudby, “Temperature effects and observation of B2u lattice mode in far infrared absorption spectrum of polyethylene,” Chem. Phys. Lett. 17(1), 84–85 (1972).
[Crossref]

van Exter, M.

D. Grischkowsky, S. R. Keiding, M. van Exter, and C. Fattinger, “Far-infrared time-domain spectroscopy with terahertz beams of dielectrics and semiconductors,” J. Opt. Soc. Am. 7(10), 2006–2015 (1990).
[Crossref]

M. van Exter, C. Fattinger, and D. Grischkowsky, “Terahertz time-domain spectroscopy of water vapor,” Opt. Lett. 14(20), 1128–1130 (1989).
[Crossref]

Veigas, B.

M. N. Costa, B. Veigas, J. M. Jacob, D. S. Santos, J. Gomes, P. V. Baptista, R. Martins, J. Inacio, and E. Fortunato, “A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper,” Nanotechnology 25(9), 094006 (2014).
[Crossref] [PubMed]

Vromans, H.

H. Vromans, A. H. De Boer, G. K. Bolhuis, C. F. Lerk, K. D. Kussendrager, and H. Bosch, “Studies on tableting properties of lactose. Part 2: Consolidation and compaction of different types of crystalline lactose,” Pharmaceutisch Weekblad-Scientific Edition 7(5), 186–193 (1985).
[Crossref] [PubMed]

Walther, M.

M. Franz, B. M. Fischer, and M. Walther, “The Christiansen effect in terahertz time-domain spectra of coarse-grained powders,” Appl. Phys. Lett. 92(2), 021107 (2008).
[Crossref]

Willart, J.-F.

R. Lefort, V. Caron, J.-F. Willart, and M. Descamps, “Mutarotational kinetics and glass transition of lactose,” Solid State Communications 140(7–8), 329–334 (2006).
[Crossref]

Willis, H. A.

J. W. Fleming, G. W. Chantry, P. A. Turner, E. A. Nicol, H. A. Willis, and M. E. A. Cudby, “Temperature effects and observation of B2u lattice mode in far infrared absorption spectrum of polyethylene,” Chem. Phys. Lett. 17(1), 84–85 (1972).
[Crossref]

Xin, X.

X. Xin, H. Altan, A. Saint, D. Matten, and R. R. Alfano, “Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature,” J. Appl. Phys. 100(9), 094905 (2006).
[Crossref]

Yoshinaga, H.

M. Hineno and H. Yoshinaga, “Far-infrared spectra of galactose and lactose at liquid He temperature,” Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy A29(2), 301–305 (1973).
[Crossref]

Zakaria, H. A.

ACS Nano (1)

Y. H. Tan, M. Liu, B. Nolting, J. G. Go, J. Gervay-Hague, and G. Liu, “A nanoengineering approach for investigation and regulation of protein immobilization,” ACS Nano 2(11), 2374–2384 (2008).
[Crossref]

Appl. Phys. Lett. (2)

M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by granular composite materials: An effective medium theory,” Appl. Phys. Lett. 100(1), 011107 (2012).
[Crossref]

M. Franz, B. M. Fischer, and M. Walther, “The Christiansen effect in terahertz time-domain spectra of coarse-grained powders,” Appl. Phys. Lett. 92(2), 021107 (2008).
[Crossref]

Appl. Spectrosc. (1)

Chem. Phys. Lett. (2)

G. D. Dean and D. H. Martin, “Inter-molecular vibrations of crystalline polyethylene and long-chain paraffins,” Chem. Phys. Lett. 1(9), 415–416 (1967).
[Crossref]

J. W. Fleming, G. W. Chantry, P. A. Turner, E. A. Nicol, H. A. Willis, and M. E. A. Cudby, “Temperature effects and observation of B2u lattice mode in far infrared absorption spectrum of polyethylene,” Chem. Phys. Lett. 17(1), 84–85 (1972).
[Crossref]

Eur. J. Pharm. Biopharm. (1)

V. Busignies, P. Tchoreloff, B. Leclerc, M. Besnard, and G. Couarraze, “Compaction of crystallographic forms of pharmaceutical granular lactoses. I. Compressibility,” Eur. J. Pharm. Biopharm. 58(3), 569–576 (2004).
[Crossref] [PubMed]

Food Chemistry (1)

K. Shiraga, Y. Ogawa, N. Kondo, A. Irisawa, and M. Imamura, “Evaluation of the hydration state of saccharides using terahertz time-domain attenuated total reflection spectroscopy,” Food Chemistry 140(1–2), 315–320 (2013).
[Crossref] [PubMed]

Infrared Phys. (1)

J. R. Birch, “The far infrared optical constants of polyethylene,” Infrared Phys. 30(2), 195–197 (1990).
[Crossref]

International J. Pharmaceutics (3)

Y. Listiohadi, J. A. Hourigan, R. W. Sleigh, and R. J. Steele, “Moisture sorption, compressibility and caking of lactose polymorphs,” International J. Pharmaceutics 359(1–2), 123–134 (2008).
[Crossref]

J. H. Kirk, S. E. Dann, and C. G. Blatchford, “Lactose: A definitive guide to polymorph determination,” International J. Pharmaceutics 334(1–2), 103–114 (2007).
[Crossref]

J. L. Crisp, S. E. Dann, M. Edgar, and C. G. Blatchford, “The effect of particle size on the dehydration/rehydration behaviour of lactose,” International J. Pharmaceutics 391(1–2), 38–47 (2010).
[Crossref]

J. Appl. Phys. (1)

X. Xin, H. Altan, A. Saint, D. Matten, and R. R. Alfano, “Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature,” J. Appl. Phys. 100(9), 094905 (2006).
[Crossref]

J. Biochem. Biophys. Methods (1)

E. R. Tovey and B. A. Baldo, “Protein binding to nitrocellulose, nylon and PVDF membranes in immunoassays and electroblotting,” J. Biochem. Biophys. Methods 19(2–3), 169–183 (1989).
[Crossref] [PubMed]

J. Immunological Methods (1)

B. T. Kurien and R. H. Scofield, “Protein blotting: A review,” J. Immunological Methods 274(1–2), 1–15 (2003).
[Crossref]

J. of Appl. Phys. (1)

M. Kaushik, B. W.-H. Ng, B. M. Fischer, and D. Abbott, “Terahertz scattering by two phased media with optically soft scatterers,” J. of Appl. Phys. 112(11), 113112 (2012).
[Crossref]

J. of Investigative Dermatology (1)

M. W. Nicholas and K. Nelson, “North, South, or East? Blotting Techniques,” J. of Investigative Dermatology 133(7), E1–E3 (2013).
[Crossref]

J. Opt. Soc. Am. (1)

D. Grischkowsky, S. R. Keiding, M. van Exter, and C. Fattinger, “Far-infrared time-domain spectroscopy with terahertz beams of dielectrics and semiconductors,” J. Opt. Soc. Am. 7(10), 2006–2015 (1990).
[Crossref]

J. Opt. Soc. Am. A (1)

Nanotechnology (1)

M. N. Costa, B. Veigas, J. M. Jacob, D. S. Santos, J. Gomes, P. V. Baptista, R. Martins, J. Inacio, and E. Fortunato, “A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper,” Nanotechnology 25(9), 094006 (2014).
[Crossref] [PubMed]

Opt. Express (1)

Opt. Lett. (1)

Pharmaceutisch Weekblad-Scientific Edition (1)

H. Vromans, A. H. De Boer, G. K. Bolhuis, C. F. Lerk, K. D. Kussendrager, and H. Bosch, “Studies on tableting properties of lactose. Part 2: Consolidation and compaction of different types of crystalline lactose,” Pharmaceutisch Weekblad-Scientific Edition 7(5), 186–193 (1985).
[Crossref] [PubMed]

Solid State Communications (1)

R. Lefort, V. Caron, J.-F. Willart, and M. Descamps, “Mutarotational kinetics and glass transition of lactose,” Solid State Communications 140(7–8), 329–334 (2006).
[Crossref]

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy (1)

M. Hineno and H. Yoshinaga, “Far-infrared spectra of galactose and lactose at liquid He temperature,” Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy A29(2), 301–305 (1973).
[Crossref]

Other (2)

C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles, (John Wiley & Sons, 1983).

P. F. Fox and P. L. H. McSweeney, Dairy Chemistry and Biochemistry (Blackie Academic & Professional, 1998).

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Figures (13)

Fig. 1
Fig. 1 Transmission-mode measurements using a Menlo Tera K15 THz time-domain spectroscopy (TDS) system, utilizing photoconductive antennas to generate and detect THz radiation. More details of the Menlo Tera K15 system are provided in Section 3.1. (a) Keeping the beam waist of the incident radiation constant, the measured signal amplitude falls as the diameter of the focal point reduces, resulting in a poorer SNR. The maximum signal amplitude (no aperture present) is normalized to one. The noise measurement is made by blocking off the THz radiation; (b) Normalized frequency responses of the plots in Fig. 1(a) show the decreasing dynamic range with decreasing aperture size.
Fig. 2
Fig. 2 A comparison of the room temperature absorption coefficients of small quantities of α-lactose monohydrate mixed with 50 mg of PE and pressed into 13 mm pellets, measured with a Menlo THz-TDS system. The spectral peaks in this frequency range are at 0.54 THz, 1.2 THz, 1.38 THz and 1.83 THz (18 cm−1, 40 cm−1, 46 cm−1 and 61 cm−1 wavenumbers respectively). The oscillatory artifact from the Fabry-Pérot etalon effect strongly masks the spectral signature for the 2 mg scenario. No useful data is obtained for a 1 mg scenario.
Fig. 3
Fig. 3 (a) A comparison of the room temperature absorption coefficients (measured with a Menlo THz-TDS system) of 100 mg α-lactose powder when pressed into a pellet consisting of (i) pure α-lactose (thick red line), (ii) mixed with 50 mg Inducos 13/1 PE with average granular diameter of 50–70 μm (blue line), and (iii) mixed with 50 mg Aldrich PE with average granular diameter of 72 μm (dashed black line); (b) When a very small quantity of sample is present in a pellet, the use of PE with smaller granular size (Inducos 13/1, 50–70 μm average diameter) as a bulking material does not enhance the spectral features of the sample.
Fig. 4
Fig. 4 Scanning electron microscope (SEM) micrograph of a layer of nitrocellulose membrane with 0.2 μm pore size, showing the network of fibers that creates the NC’s micropore structure. The white scale bar represents 2 μm.
Fig. 5
Fig. 5 Three views of the copper sample holder designed to facilitate the loading of samples and sandwiching to create the double-layered NC structure. (Top) empty holder; (middle) loaded with NC; (bottom) sandwich structure. This sample holder is used for measurements made at the Australian Synchrotron at 77 K under vacuum.
Fig. 6
Fig. 6 (a) Absorption coefficients α of various double-layered NC structures and PE from 0.2–1.8 THz at 298 K, measured with a THz-TDS system. The peaks in αNC are due to residual water vapor lines. The overall αNC profiles are smooth as shown by the fitted curves. Although αNC is not as flat and low as αPE, it still possesses good THz transmissivity with no etalon artifacts; (b) Refractive indices n of various double-layered NC structures and PE from 0.2–1.8 THz at 298 K. Like nPE, the nNC profiles are flat across the frequency of interest. The peaks along nNC correspond to water vapor lines.
Fig. 7
Fig. 7 Absorption coefficients α of various NC and PE samples from 1.5–19 THz at 77 K, measured with a synchrotron THz source. Here, αPE of both types of PE are lower than αNC at lower frequencies but rise significantly at higher frequencies, with αPE of the Aldrich PE surpassing αNC from 7 THz onwards. The spectral peaks of PE at 3.2 THz and 7.2 THz are consistent with that in literature [1113].
Fig. 8
Fig. 8 SEM micrograph of dry α-lactose powder on a layer of NC with 0.2 μm pore size. The white scale bar represents 50 μm.
Fig. 9
Fig. 9 SEM micrograph of damp α-lactose crystal on a layer of NC with 0.2 μm pore size. This crystal has caked as a result of hydration. The white scale bar represents 2 μm.
Fig. 10
Fig. 10 Compared to the pure pellet, there is significantly less masking by etalon artifacts in the NC-held samples, resulting in the clear revelation of the smaller spectral peak at 1.2 THz, particularly for the 2 mg NC-held sample. No signal processing has been applied to enhance these plots.
Fig. 11
Fig. 11 (a) Absorption coefficients from 0.6–8.1 THz at 77 K and 298 K, measured with a synchrotron THz source. The circle highlights the weak peak at 2.21 THz that is most visible for the pure pellet; (b) There is excellent overlap of the troughs from the 77 K NC-held sample and the 3 mm pure pellet, with similar rising baselines that is likely due to scattering by the α-lactose crystals. The peaks of the 298 K NC-held sample are red shifted; (c) The etalon artifacts are most prominent at low frequencies for both mixed pellets. The rise in baseline for the pellet containing Aldrich PE is very distinct from that of the other two samples.
Fig. 12
Fig. 12 Plots from Fig 11(a) after scattering mitigation using Mie theory with α-lactose parameters. The rising baselines seen in Fig 11(a) are reduced in this figure, allowing for more accurate representations of the samples’ optical properties.
Fig. 13
Fig. 13 Scattering profiles used to reduce the rising baselines of the two 7 mm pellet-held samples. The factor N = 1/20 is needed to scale the scattering profiles within the limits of α. Modeling scattering with PE as a dominant scatterer yields improved mitigation over that attained in Fig. 12 where α-lactose is assumed to be the dominant scatterer.

Tables (1)

Tables Icon

Table 1 Wavenumbers of the spectral peaks of anhydrous lactose at 4 K and 298 K [23], and α-lactose monohydrate at 77 K and 298 K (this work with a synchrotron THz source). The letter symbols in parentheses indicate the relative absorption intensity: s = strong, m = medium, w = weak, w? = very weak/doubtful. The X symbol indicates band not reported or not observed; the — symbol indicates no data available (signal exceeds either minimum or maximum detection limits). Ald. = Aldrich, Ind. = Inducos 13/1. The peaks shift toward lower wavenumbers (red shift) at higher measurement temperatures. Anhydrous lactose contains both α-lactose and β -lactose anomers thus may contain more bands (e.g. 83.5 cm−1 and 215 cm−1 wavenumbers) than those obtained in this study where ≥96% α-lactose anomers are present. On line 17 (209 cm−1 wavenumbers) for the samples tested in this work, the cluster of peaks are likely to be from one strong, broad peak that has exceeded the maximum detection limit, splintering into several smaller but distinct peaks.

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