Plant-Derived and Synthetic Nicotine in E-Cigarettes: Is Differentiation with NMR Spectroscopy Possible?

To circumvent regulatory frameworks, many producers start to substitute plant-derived nicotine (tobacco-derived nicotine, TDN) by synthetic nicotine (tobacco-free nicotine, TFN) in e-cigarette products. Due to the higher costs of enantiomeric synthesis and purification of TFN, there is a need to develop an analytical method that clearly distinguishes between the two sources. To trace nicotine's origin, its enantiomeric purity can be postulated by H NMR spectroscopy using ()-(-)-1,1'-binaphthyl-2,2'-diyl hydrogen phosphate (BNPPA) as a chiral complexing agent.

Nuclear magnetic resonance spectroscopy as an elegant tool for a complete quality control of crude heparin material.

Nuclear magnetic resonance (NMR) spectrometric methods for the quantitative analysis of pure heparin in crude heparin is proposed. For quantification, a two-step routine was developed using a USP heparin reference sample for calibration and benzoic acid as an internal standard. The method was successfully validated for its accuracy, reproducibility, and precision.

Is the Calibration Transfer of Multivariate Calibration Models between High- and Low-Field NMR Instruments Possible? A Case Study of Lignin Molecular Weight.

Although several successful applications of benchtop nuclear magnetic resonance (NMR) spectroscopy in quantitative mixture analysis exist, the possibility of calibration transfer remains mostly unexplored, especially between high- and low-field NMR. This study investigates for the first time the calibration transfer of partial least squares regressions [weight average molecular weight () of lignin] between high-field (600 MHz) NMR and benchtop NMR devices (43 and 60 MHz). For the transfer, piecewise direct standardization, calibration transfer based on canonical correlation analysis, and transfer via the extreme learning machine auto-encoder method are employed.

Benchtop versus high field NMR: Comparable performance found for the molecular weight determination of lignin.

Lignin is a promising renewable biopolymer being investigated worldwide as an environmentally benign substitute of fossil-based aromatic compounds, e.g. for the use as an excipient with antioxidant and antimicrobial properties in drug delivery or even as active compound.

Multinuclear NMR screening of pharmaceuticals using standardization by H integral of a deuterated solvent.

NMR standardization approach that uses the H integral of deuterated solvent for quantitative multinuclear analysis of pharmaceuticals is described. As a proof of principle, the existing NMR procedure for the analysis of heparin products according to US Pharmacopeia monograph is extended to the determination of Na and Cl content in this matrix. Quantification is performed based on the ratio of a Na (Cl) NMR integral and H NMR signal of deuterated solvent, DO, acquired using the specific spectrometer hardware.

Is NMR Combined with Multivariate Regression Applicable for the Molecular Weight Determination of Randomly Cross-Linked Polymers Such as Lignin?

The molecular weight properties of lignins are one of the key elements that need to be analyzed for a successful industrial application of these promising biopolymers. In this study, the use of H NMR as well as diffusion-ordered spectroscopy (DOSY NMR), combined with multivariate regression methods, was investigated for the determination of the molecular weight ( and ) and the polydispersity of organosolv lignins ( = 53, , , and ). The suitability of the models was demonstrated by cross validation (CV) as well as by an independent validation set of samples from different biomass origins (beech wood and wheat straw).

Is infrared spectroscopy combined with multivariate analysis a promising tool for heparin authentication?

The investigation of the possibility to determine various characteristics of powder heparin (n = 115) was carried out with infrared spectroscopy. The evaluation of heparin samples included several parameters such as purity grade, distributing company, animal source as well as heparin species (i.e.

Novel approach of qNMR workflow by standardization using 2H integral: Application to any intrinsic calibration standard.

Quantitative nuclear magnetic resonance (qNMR) is routinely performed by the internal or external standardization. The manuscript describes a simple alternative to these common workflows by using NMR signal of another active nuclei of calibration compound. For example, for any arbitrary compound quantification by NMR can be based on the use of an indirect concentration referencing that relies on a solvent having both 1H and 2H signals.

Quality Control of Heparin Injections: Comparison of Four Established Methods.

Heparin is an anticoagulant medication that is usually injected subcutaneously. The quality of a set of commercial heparin injections from different producers was examined by NMR, IR, UV-Vis spectroscopies and potentiometric multisensor system. The type of raw material regarding heparin animal origin and producer, heparin molecular weight and activity values were derived based on the non-targeted analysis of H NMR fingerprints.

Distinguishing paracetamol formulations: Comparison of potentiometric "Electronic Tongue" with established analytical techniques.

Fast and inexpensive analytical tools for identification of the origin of pharmaceutical formulations are important to ensure consumers safety. This study explores the potential of potentiometric multisensor systems ("electronic tongues") in this type of application. 72 paracetamol samples purchased in different countries and produced by various companies were studied via infrared spectroscopy (IR), near infrared spectroscopy (NIR), nuclear magnetic resonance spectroscopy (NMR) and multisensor system (ET).

Extraction of High-Purity Lignins via Catalyst-free Organosolv Pulping from Low-Input Crops.

A catalyst-free organosolv pulping process was applied to cup plant (, S), Miscanthus grass (, M), and the Paulownia tree (, P), resulting in high-purity lignins with no signals for cellulose, hemicellulose, or other impurities in two-dimensional heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectra. Different biomass particle sizes used for the organosolv pulping (1.6-2.

Independent components analysis (ICA) at the "cocktail-party" in analytical chemistry.

Independent components analysis (ICA) is a probabilistic method, whose goal is to extract underlying component signals, that are maximally independent and non-Gaussian, from mixed observed signals. Since the data acquired in many applications in analytical chemistry are mixtures of component signals, such a method is of great interest. In this article recent ICA applications for quantitative and qualitative analysis in analytical chemistry are reviewed.

Anticoagulant activity of porcine heparin: Structural-property relationship and semi-quantitative estimation by nuclear magnetic resonance (NMR) spectrometry.

Heparin is a carbohydrate polymer, which is clinically used as an anticoagulant for the treatment of thrombotic disorders. The anticoagulant process is mainly mediated by the interaction of heparin with antithrombin followed by inhibition of clotting factors IIa (FIIa) and Xa (FXa). The influence of polymer disaccharide structure, average molecular weight and impurity profiling (e.

Retrospective multivariate analysis of pharmaceutical preparations using H nuclear magnetic resonance (NMR) spectroscopy: Example of 990 heparin samples.

NMR spectroscopy has become an essential diagnostic tool for pharmaceutical preparations worldwide, with many runs performed annually on a routine basis. In this study multivariate analysis was performed on a big dataset of 990 NMR heparin spectra recorded over six years (2012-2017) in our laboratory. Several steps of statistical analysis of accumulated data were used to differentiate samples according to animal origin (bovine, porcine and ovine heparin), purity grade (crude and purified heparin), distributing company as well as to estimate their closeness to the heparin reference sample (SST) provided by US Pharmacopeia.

Automated multicomponent phospholipid analysis using P NMR spectroscopy: example of vegetable lecithin and krill oil.

Nuclear magnetic resonance (NMR) spectroscopy is widely applied in the field of metabolomics due to its quantitative nature and the reproducibility of data generated. However, one of the main challenges in routine NMR analysis is to obtain valuable information from large datasets of raw data in a high-throughput, automatic, and reproducible manner. In this study, a method to automatically annotate and quantify 12 phospholipids (PLs) in vegetable lecithin (soy, sunflower, rape) and krill oil is introduced.

Monitoring daily routine performance in quantitative NMR (qNMR) spectroscopy: Is the system suitability test necessary?

Nuclear magnetic resonance spectrometry (NMR) finds numerous applications in pharmacy, cosmetic, and food control as well as in developing tools for "big data" analysis. However, there remains a need for automated tools to assess instrument system suitability in real time for each particular routine sample. An automated procedure has been introduced to monitor a number of characteristics (resolution, symmetry, and half width) in real time after the measurement of two samples distributed by the vendor (0.

Nuclear magnetic resonance spectroscopy as a tool for the quantitative analysis of water and ions in pharmaceuticals: Example of heparin.

Heparin is a linear, highly sulfated glycosaminoglycan (GAG), which consists of repeating disaccharide units of β-d-glucuronic acid or α-l-iduronic acid and α-d-glucosamine. While robust analytical approaches exist for the characterization of organic composition of heparin preparations, there is a lack of methods for the simultaneous quantification of inorganic compounds (water, anions, cations) in this matrix. A nuclear magnetic resonance (NMR) spectrometric method for heparin characterization described in US Pharmacopeia was extended to simultaneous analysis of the inorganic ions (sodium, calcium, and chloride), acetate as well as water content.

Improving reliability of chemometric models for authentication of species origin of heparin by switching from 1D to 2D NMR experiments.

Nuclear magnetic resonance (NMR) spectroscopy is regarded as one of the most powerful and versatile analytical approaches to assure the quality of heparin preparations. In particular, it was recently demonstrated that by using H NMR coupled with chemometrics heparin and low molecular weight heparin (LMWH) samples derived from three major animal species (porcine, ovine and bovine) can be differentiated [Y.B.

Novel method for the determination of average molecular weight of natural polymers based on 2D DOSY NMR and chemometrics: Example of heparin.

Apart from the characterization of impurities, the full characterization of heparin and low molecular weight heparin (LMWH) also requires the determination of average molecular weight, which is closely related to the pharmaceutical properties of anticoagulant drugs. To determine average molecular weight of these animal-derived polymer products, partial least squares regression (PLS) was utilized for modelling of diffused-ordered spectroscopy NMR data (DOSY) of a representative set of heparin (n=32) and LMWH (n=30) samples. The same sets of samples were measured by gel permeation chromatography (GPC) to obtain reference data.

Authentication of animal origin of heparin and low molecular weight heparin including ovine, porcine and bovine species using 1D NMR spectroscopy and chemometric tools.

High resolution (600MHz) nuclear magnetic resonance (NMR) spectroscopy is used to distinguish heparin and low-molecular weight heparins (LMWHs) produced from porcine, bovine and ovine mucosal tissues as well as their blends. For multivariate analysis several statistical methods such as principal component analysis (PCA), factor discriminant analysis (FDA), partial least squares - discriminant analysis (PLS-DA), linear discriminant analysis (LDA) were utilized for the modeling of NMR data of more than 100 authentic samples. Heparin and LMWH samples from the independent test set (n=15) were 100% correctly classified according to its animal origin.

Current role and future perspectives of multivariate (chemometric) methods in NMR spectroscopic analysis of pharmaceutical products.

Nuclear magnetic resonance (NMR) is a fast and accurate analytical method. Associated with chemometrics, it gradually becomes more important tool for the pharmaceutical industry. In this review studies dealing with the applications of multivariate analysis to NMR spectroscopic profiles were grouped and discussed according to the analytical problem solved.

Practical guide for selection of H qNMR acquisition and processing parameters confirmed by automated spectra evaluation.

In our recent paper, a new technique for automated spectra integration and quality control of the acquired results in qNMR was developed and validated (Monakhova & Diehl, Magn. Res. Chem.

Multicomponent quantitative spectroscopic analysis without reference substances based on ICA modelling.

A fast and reliable spectroscopic method for multicomponent quantitative analysis of targeted compounds with overlapping signals in complex mixtures has been established. The innovative analytical approach is based on the preliminary chemometric extraction of qualitative and quantitative information from UV-vis and IR spectral profiles of a calibration system using independent component analysis (ICA). Using this quantitative model and ICA resolution results of spectral profiling of "unknown" model mixtures, the absolute analyte concentrations in multicomponent mixtures and authentic samples were then calculated without reference solutions.

Facilitating the performance of qNMR analysis using automated quantification and results verification.

Quantitative nuclear magnetic resonance (qNMR) is considered as a powerful tool for measuring the absolute amount of small molecules in complex mixtures. However, verification of the accuracy of such quantification is not a trivial task. In particular, preprocessing and integration steps are challenging and potentially erroneous.