Adsorption of purpald SAMs on silver and gold electrodes: a Raman mapping study

The adsorption modes of 4‐amino‐3‐hydrazino‐5‐mercapto‐1,2,4‐trizole (purpald) self‐assembled monolayers (SAMs) formed on SERS‐active silver and gold electrodes were comparatively studied using surface‐enhanced Raman scattering (SERS), and the self‐assembling procedures were investigated by the Raman mapping technique. Purpald SAMs adopted a titled orientation with S, N2 atoms anchoring to the silver electrode and the  N7H₂ close to the surface, whereas purpald stood up on the gold electrode through S, N5 atoms and with  N8H₂ adjacent to the surface. The density functional theory (DFT) at the level of B3LYP was performed to help explain their different adsorption behaviors on the silver and gold electrodes. Copyright © 2006 John Wiley & Sons, Ltd.     

Linear quantification calibration of crystallinity at subpercent and its evaluation based on spectral and spatial information inherited in Raman chemical images

In this paper, the author reported two methods to extract spectral or spatial information inherited in the Raman chemical images for linear quantification calibration of crystallinity. The two approaches reported quantification results according to the spectral mean score of overall pixels or the spatial percentage of the pixels with a score greater than and equal to the threshold of the chemical images, respectively. From this study, it can be concluded that, first, sampling method for data collection in mapping has to be optimized to achieve linear quantification calibration through simple univariate analysis approaches. Second, the ordinary way of evaluating/validating a linear quantification technique by best linear correlation coefficient (R²) and root‐mean‐square error of calibration is disputable and has to be reconsidered. Lastly, with further consideration of root‐mean‐square relative error of calibration and predicted crystallinity at subpercent, it was found that the spectral mean score method cannot generate reliable quantification results at subpercent crystallinity. Copyright © 2014 John Wiley & Sons, Ltd.