Filter-based infrared detectors for high temperature size exclusion chromatography analysis of polyolefins: Calibration with a small number of standards and error analysis

Characterization of Chemical Composition along the Molar Mass Distribution in Polyolefin Copolymers by GPC Using a Modern Filter‐Based IR Detector

“…the methyl sensitive channel over the total concentration channel). Different correlations to chemical composition are found for different analytical signals, and it is possible to compare their performance by using statistical parameters based on the confidence interval of the calibration lines …”

“…The approach used to obtain the error bars along the chromatogram was proposed by the authors, and makes use of the noise level of the absorbance chromatograms measured along the analyses, and the calibration straight‐line slope. Given that the noise level may vary for different experiments due to solvent quality or other external factors, the fact that this method is based on noise determination close in time to the actually measured data makes the estimated uncertainty more realistic.…”

“…The high SNR associated to modern filter‐based IR detectors, and also the simplicity in data processing, allows an important reduction on the requirement for relatively large sample concentration to get reliable data. In previous work, a minimal concentration of 0.009 mg/mL was estimated to be required at the detector cell with filter‐based IR detectors, in order to keep the errors below one unit of CH 3 /1000TC. This limit is substantially smaller than the quantification limit reported for an on‐line GPC‐FTIR method based on full spectrum data processing, established as 0.065 mg/mL .…”

“…Linearity and sensitivity as mass detector is assessed, as well as the minor influence of the chemical nature of the analyzed PO in the detector response factor. A calibration procedure for quantifying chemical composition using a small set of reference materials is described in some detail for both homogeneous and heterogeneous polymer references . The error in the SCB determination, estimated with an equation based on the background noise in the absorbance signals and the slope of the calibration straight‐line, is compared to the error obtained from replicate analysis, proving to be reliable.…”

Analysis of Propylene‐1‐Butene Copolymer Composition by GPC with Online Detectors

“…This calibration approach is based on using a limited set of reference samples, in line with previously published work. [23] A triple detector GPC system, which consists of the combination of the sizebased separation by GPC with a light scattering detector (LS), a capillary viscometer and a concentration detector, allows the accurate determination of MMD, and also the study of the polymer molecular architecture. [24][25][26][27] Variation in the Mark-Houwink (MH) plot (log-log plot of intrinsic viscosity against molar mass), and in the related conformation plot (log-log plot of radius of gyration against molar mass), in correlation with SCB or comonomer content in polyethylene (PE) have been described in literature, [28,29] basically as a decrease in the intercept value with increasing SCB level.…”