of the surface to be determined. It is clear that the red spectrum almost overlaps the blue benzoic acid standard curve. This provides evidence that benzoic acid was coated on the MCC and was aggregated locally as shown on the confocal image.
It is apparent from the images that the MCC surface is not atomically smooth and this translates to the observed covering of the benzoic acid surface coating, which was preferentially retained in the surface troughs; this is in agreement with the results obtained from SEM analysis. This is also confirmed by scanning a point on the surface where the coating was thinner which gave a spectrum showing evidence of both active and MCC (not shown). Ferrocene, phenanthrene and vitamin K3 on MCC showed similar confocal Raman results, with the distribution of these respective actives on the MCC clearly seen.
In contrast, two actives, adamantane and stearic acid, showed no evidence of coating using confocal Raman analysis. The loading of adamantane on MCC was found to be the lowest in this work
at only 0.12 mg/g. The confocal Raman spectroscopy results were therefore inconclusive due to the low loading, though the mass balance and SEM (see below) corroborate that active was present on the MCC surface. Stearic acid has very similar standard feature peaks at wavenumbers very close to those of the MCC standard, and this therefore made it difficult to distinguish stearic acid from the MCC by confocal Raman spectroscopy. Several attempts were made but drew inconclusive results.
3.1.2.2. SEM analysis. The SEM images of coated and control MCC (for comparison) are shown in Fig. 4 In all images the scale bar is 200 nm. The images imply that for all the actives studied the coating on the MCC particles were in the nanosize range. There is evidence on the images that the visible feature size is much below the 200 nm scale bar. In some instances particularly Images 4b and 4d, the coating appeared as a continuous thin layer closely following the undulations of the MCC surface. Although the particle size
of the surface to be determined. It is clear that the red spectrum almost overlaps the blue benzoic acid standard curve. This provides evidence that benzoic acid was coated on the MCC and was aggregated locally as shown on the confocal image.It is apparent from the images that the MCC surface is not atomically smooth and this translates to the observed covering of the benzoic acid surface coating, which was preferentially retained in the surface troughs; this is in agreement with the results obtained from SEM analysis. This is also confirmed by scanning a point on the surface where the coating was thinner which gave a spectrum showing evidence of both active and MCC (not shown). Ferrocene, phenanthrene and vitamin K3 on MCC showed similar confocal Raman results, with the distribution of these respective actives on the MCC clearly seen.In contrast, two actives, adamantane and stearic acid, showed no evidence of coating using confocal Raman analysis. The loading of adamantane on MCC was found to be the lowest in this workat only 0.12 mg/g. The confocal Raman spectroscopy results were therefore inconclusive due to the low loading, though the mass balance and SEM (see below) corroborate that active was present on the MCC surface. Stearic acid has very similar standard feature peaks at wavenumbers very close to those of the MCC standard, and this therefore made it difficult to distinguish stearic acid from the MCC by confocal Raman spectroscopy. Several attempts were made but drew inconclusive results.3.1.2.2. SEM analysis. The SEM images of coated and control MCC (for comparison) are shown in Fig. 4 In all images the scale bar is 200 nm. The images imply that for all the actives studied the coating on the MCC particles were in the nanosize range. There is evidence on the images that the visible feature size is much below the 200 nm scale bar. In some instances particularly Images 4b and 4d, the coating appeared as a continuous thin layer closely following the undulations of the MCC surface. Although the particle size
การแปล กรุณารอสักครู่..
