Fourier transform infrared spectroscopy with a sample deposition interface as a quantitative detector in size-exclusion chromatography.
The use of a state-of-the-art commercial solvent-elimination interface for liquid chromatography-infrared spectroscopy is discussed from the perspective of quantitative analysis. The effect of eluent flow-rate is investigated with respect to the homogeneity of the deposit and the trace width along the deposition trace. Low flow-rates (50 microl/min or less) turn out to be favorable for obtaining a good trace and a high sensitivity. The trace width decreased from 2.20 to 1.13 mm when the flow-rate was reduced from 500 to 25 microl/min. Preservation of chromatographic detail during deposition was evaluated at different substrate moving speeds. The additional (extra-column) band broadening that is inherent to nebulizer-deposition interfaces, causes a loss in resolution in size-exclusion chromatography (SEC)-Fourier transform infrared (FTIR) spectroscopy in comparison with SEC-UV. The repeatability of the deposition is evaluated by SEC-FTIR analyses of polystyrene standards (peak molar-masses: 1250-2,950 000 g/mol) and the RSD is found to range from 3.2 to 5.8% in response and from 0.21 to 0.47% in retention time.
Kok
S J
SJ
TNO Chemistry, Packaging Research and Polymer Analysis Department, Utrechtseweg 48, 3704 HE Zeist, The Netherlands. skok@voeding.tno.nl
Arentsen
N C
NC
Cools
P J C H
PJ
Hankemeier
Th
T
Schoenmakers
P J
PJ
D002850:Chromatography, Gel / Q000379:methods*; D007202:Indicators and Reagents; D011137:Polystyrenes / Q000737:chemistry; D012015:Reference Standards; D015203:Reproducibility of Results; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
D007202:Indicators and Reagents; D011137:Polystyrenes; D012997:Solvents