At-Line Monitoring of the Extraction Process of Rosmarini Folium via Wet Chemical Assays, UHPLC Analysis, and Newly Developed Near-Infrared Spectroscopic Analysis Methods

Abstract

The present study demonstrates the applicability of at-line monitoring of the extraction process of Rosmarinus officinalis L. leaves (Rosmarini folium) and the development of near-infrared (NIR) spectroscopic analysis methods. Therefore, whole dried Rosmarini folium samples were extracted by maceration with 70% (v/v) ethanol. For the experimental design three different specimen-taking plans were chosen. At first, monitoring was carried out using three common analytical methods: (a) total hydroxycinnamic derivatives according to the European Pharmacopoeia, (b) total phenolic content according to Folin–Ciocalteu, and (c) rosmarinic acid content measured by UHPLC-UV analysis. Precision validation of the wet chemical assays revealed a repeatability of (a) 0.12% relative standard deviation (RSD), (b) 1.1% RSD, and (c) 0.28% RSD, as well as an intermediate precision of (a) 4.1% RSD, (b) 1.3% RSD, and (c) 0.55% RSD. The collected extracts were analyzed with a NIR spectrometer using a temperature-controlled liquid attachment. Samples were measured in transmission mode with an optical path length of 1 mm. The combination of the recorded spectra and the previously obtained analytical reference values in conjunction with multivariate data analysis enabled the successful establishment of partial least squares regression (PLSR) models. Coefficients of determination (R2) were: (a) 0.94, (b) 0.96, and (c) 0.93 (obtained by test-set validation). Since Pearson correlation analysis revealed that the reference analyses correlated with each other just one of the PSLR models is required. Therefore, it is suggested that PLSR model (b) be used for monitoring the extraction process of Rosmarini folium. The application of NIR spectroscopy provides a fast and non-invasive alternative analysis method, which can subsequently be implemented for on- or in-line process control.

Near-Infrared Spectroscopy in Bio-Applications

“…Delueg et al developed on-line monitoring strategy for the extraction process of Rosmarini folium based on a combination of wet chemical assays, ultra-HPLC with UV detector (UHPLC-UV) analysis, and NIR spectroscopic analysis method [78]. The combination of the measured NIR spectra and the analytical reference values (total hydroxycinnamic derivatives, total phenolic content and RA content) enabled successful construction of a PLS regression model with coefficients of determination (R 2 ) of 0.96 obtained by test-set validation.…”

Advances in Near Infrared Spectroscopy and Related Computational Methods

“…However, for sake of clarity a tentative and brief overview of these contributions may be helpful to present the Special Issue to the readership. The majority of the articles focuses on applied qualitative and quantitative analyses in a variety of fields [9,11,12,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. Roughly, half of these may be associated with pharmaceutical and medical applications [17][18][19][20][21][22][23][24].…”

“…The majority of the articles focuses on applied qualitative and quantitative analyses in a variety of fields [9,11,12,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. Roughly, half of these may be associated with pharmaceutical and medical applications [17][18][19][20][21][22][23][24]. Most of the remaining applied studies were directed at agricultural applications [25][26][27][28][29][30][31][32][33][34], well reflecting the ever-growing significance of NIR spectroscopy in this area; a good perspective of this topic is included in a focused review article published in the Special Issue [30].…”

Advances in Near-Infrared Spectroscopy and Related Computational Methods

“…The Special Issue has met a remarkably positive feedback with many contributions submitted by numerous scholars and professional spectroscopists performing their active research in academia and industry, resulting in a collection of 30 publications including two exhaustive review articles [7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36]. The diversity in the application field has been well represented by the submitted manuscripts.…”

“…However, for sake of clarity a tentative and brief overview of these contributions may be helpful to present the Special Issue to the readership. The majority of the articles focuses on applied qualitative and quantitative analyses in a variety of fields [9,11,12,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34]. Roughly, half of these may be associated with pharmaceutical and medical applications [17,18,19,20,21,22,23,24].…”