KELES, Hakan, NAYLOR, Andrew, CLEGG, Francis and SAMMON, Chris (2014). The application of non-linear curve fitting routines to the analysis of mid-infrared images obtained from single polymeric microparticles. Analyst, 139 (10), p. 2355.
![]()
|
PDF (Gold open access)
c3an01879b.pdf - Published Version Creative Commons Attribution. Download (1MB) | Preview |
Abstract
For the first time, we report a series of time resolved images of a single PLGA microparticle undergoing hydrolysis at 70 °C that have been obtained using attenuated total reflectance-Fourier transform infrared spectroscopic (ATR-FTIR) imaging. A novel partially supervised non-linear curve fitting (NLCF) tool was developed to identify and fit peaks to the infrared spectrum obtained from each pixel within the 64 × 64 array. The output from the NLCF was evaluated by comparison with a traditional peak height (PH) data analysis approach and multivariate curve resolution alternating least squares (MCR-ALS) analysis for the same images, in order to understand the limitations and advantages of the NLCF methodology. The NLCF method was shown to facilitate consistent spatial resolution enhancement as defined using the step-edge approach on dry microparticle images when compared to images derived from both PH measurements and MCR-ALS. The NLCF method was shown to improve both the S/N and sharpness of images obtained during an evolving experiment, providing a better insight into the magnitude of hydration layers and particle dimension changes during hydrolysis. The NLCF approach facilitated the calculation of hydrolysis rate constants for both the glycolic (kG) and lactic (kL) acid segments of the PLGA copolymer. This represents a real advantage over MCR-ALS which could not distinguish between the two segments due to colinearity within the data. The NLCF approach made it possible to calculate the hydrolysis rate constants from a single pixel, unlike the peak height data analysis approach which suffered from poor S/N at each pixel. These findings show the potential value of applying NLCF to the study of real-time chemical processes at the micron scale, assisting in the understanding of the mechanisms of chemical processes that occur within microparticles and enhancing the value of the mid-IR ATR analysis.
Item Type: | Article |
---|---|
Additional Information: | Published as Gold open access. Paid by RSC Gold voucher |
Research Institute, Centre or Group - Does NOT include content added after October 2018: | Materials and Engineering Research Institute > Advanced Coatings and Composites Research Centre > Polymers, Composites and Spectroscopy Group |
Identification Number: | https://doi.org/10.1039/C3AN01879B |
Page Range: | p. 2355 |
Depositing User: | Ann Betterton |
Date Deposited: | 12 May 2014 12:52 |
Last Modified: | 18 Mar 2021 07:52 |
URI: | https://shura.shu.ac.uk/id/eprint/8081 |
Actions (login required)
![]() |
View Item |
Downloads
Downloads per month over past year