Quantitative molecular analysis with molecular bands emission using laser-induced breakdown spectroscopy and chemometrics

Abstract

The present work describes the first quantitative molecular prediction using laser-induced molecular bands along with chemometrics. In addition, this spectroscopic procedure has demonstrated the first complete quantitative analysis utilizing traditionally insensitive elements for pharmaceutical formulations. Atomic LIBS requires certain sensitive elements, such as Cl, F, Br, S and P, in order to quantitate a specific organic compound in a complex matrix. Molecular LIBS has been demonstrated to be the first successful approach using atomic spectroscopy to evaluate a complex organic matrix. This procedure is also the first quantitative analysis using laser-induced molecular bands and chemometrics. We have successfully applied chemometrics to predict the formulation excipients and active pharmaceutical ingredient (API) in a complex pharmaceutical formulation. Using such an approach, we demonstrate that the accuracy for the API and a formulation lubricant, magnesium stearate, have less than 4% relative bias. The other formulation excipients such as Avicel Ò and lactose have been accurately predicted to have less than a 15% relative bias. Molecular LIBS and chemometrics have provided a novel approach for the quantitative analysis of several molecules that was not technically possible with the traditional atomic LIBS procedure, that required sensitive elements to be present in both API and formulation excipients.

Calibration-Free Laser-Induced Breakdown Spectroscopy: State of the art

“…In Baudelet et al [62] it is shown that molecular emission in femtosecond plasmas is greater than in plasma obtained by nanosecond irradiation. Doucet et al [63] combined chemometrics with intensity of molecular emission in LIBS to measure the composition of pharmaceutical formulations. The authors used standards to calibrate their method and no information was provided on the relative proportion of atoms and molecules in the plasma.…”

Comparison of univariate and multivariate calibration for the determination of micronutrients in pellets of plant materials by laser induced breakdown spectrometry

“…Quantitative methods employing multivariate calibration, such as those based on partial least squares regression (PLSR) [4][5][6][7]10,[28][29][30][31][32][33][34][35][36][37][38][39][40][41][42], principal component regression (PCR) [7,32,33,41,43,44], multi-linear regression (MLR) [32] or artificial neural networks (ANN) [30,45,46] have been found. PLSR applications were used to predict the main elemental composition [36,37] and characterization [38] of samples of the jewelry industry and its application to study the matrix effects in steel samples [40,41].…”

In-Field, In Situ, and In Vivo 3-Dimensional Elemental Mapping for Plant Tissue and Soil Analysis Using Laser-Induced Breakdown Spectroscopy

“…During the LIBS measurement process, the plasma spectrum contains spectral characteristics of atom, iron, and molecule fragments, but we only used the atomic spectral line in this study. For certain specific measurements, the spectral characteristics of molecular fragments can be observed and used to directly image the molecular distributions [41,46,47,48]. Theoretically, LIBS can measure nearly all elements, but it is a problem for elements that exist in air, e.g., C, H, and O.…”