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Journal ArticleDOI

Synthetic fentanyls evaluation and characterization by infrared spectroscopy employing in silico methods

TL;DR: In this article, the authors applied factorial design to decide the best conditions to perform quantum calculations to obtain the infrared spectra of 46 seized nonpharmaceutical fentanyls (NPFs) and used multivariate classification to establish the main spectral characteristics of these substances.
About: This article is published in Computational and Theoretical Chemistry.The article was published on 2021-10-01. It has received 2 citations till now.
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Journal ArticleDOI
TL;DR: In this article, the Pearson correlation coefficient was used to compare the agreement of the experimental infrared spectra from the NIST Chemistry Web book with the calculated spectra using standard harmonic frequency analysis and spectra extracted from ab initio molecular dynamics simulations at different levels of theory.
Abstract: Experimentally measured infrared spectra are often compared to their computed equivalents. However, the accordance is typically characterized by visual inspection, which is prone to subjective judgment. The primary challenge for a similarity-based analysis is that the artifacts introduced by each approach are very different and, therefore, may require preprocessing steps to determine and correct impeding irregularities. To allow for automated objective assessment, we propose a practical and comprehensive workflow involving scaling factors, a novel baseline correction scheme, and peak smoothing. The resulting spectra can then easily be compared quantitatively using similarity measures, for which we found the Pearson correlation coefficient to be the most suitable. The proposed procedure is then applied to compare the agreement of the experimental infrared spectra from the NIST Chemistry Web book with the calculated spectra using standard harmonic frequency analysis and spectra extracted from ab initio molecular dynamics simulations at different levels of theory. We conclude that the direct, quantitative comparison of calculated and measured IR spectra might become a novel, sophisticated approach to benchmark quantum-chemical methods. In the present benchmark, simulated spectra based on ab initio molecular dynamics show in general better agreement with the experiment than static calculations.

7 citations

Book ChapterDOI
01 Feb 2008

7 citations

Book ChapterDOI
16 Apr 2006

6 citations

Journal ArticleDOI
TL;DR: In this article, the role of the Grimme's D3 correction for the dispersion forces was additionally considered for each medium, and the correction appeared to influence more the gas phase than water dissolved structures.

6 citations

Book ChapterDOI
11 Mar 2016

5 citations