Publications by authors named "Bernd Diehl"

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.

View Article and Find Full Text PDF

Edible insects with high fat and phosphorus content are a potential novel source of lecithin, however, studies on their minor lipids are limited. In this study, lecithin was extracted from black soldier fly larvae and yellow mealworm. Herein, the effects of lecithin extraction method, matrix and ultrasound pretreatment were explored based on the fatty acid composition and phospholipid profile with soy lecithin as a reference.

View Article and Find Full Text PDF

With the prevalence of glucosamine- and chondroitin-containing dietary supplements for people with osteoarthritis in the marketplace, it is important to have an accurate and reproducible analytical method for the quantitation of these compounds in finished products. NMR spectroscopic method based both on low- (80 MHz) and high- (500-600 MHz) field NMR instrumentation was established, compared and validated for the determination of chondroitin sulfate and glucosamine in dietary supplements. The proposed method was applied for analysis of 20 different dietary supplements.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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).

View Article and Find Full Text PDF

The goal of the qNMR Summit is to take stock of the status quo and the recent developments in qNMR research and applications in a timely and accurate manner. It provides a platform for both advanced and novice qNMR practitioners to receive a well-rounded update and discuss potential qNMR-related applications and collaborations. For over a decade, scientists from academia, industry, nonprofit institutions, and governmental bodies have focused on the standardization of qNMR methodology, as well as its metrological and pharmacopeial utility.

View Article and Find Full Text PDF

As a low-input crop, offers numerous advantages that, in addition to agricultural applications, permits its exploitation for energy, fuel, and material production. Depending on the genotype, season, and harvest time as well as plant component (leaf versus stem), correlations between structure and properties of the corresponding isolated lignins differ. Here, a comparative study is presented between lignins isolated from , , and using a catalyst-free organosolv pulping process.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF
Article Synopsis
  • NMR spectroscopy is being used to precisely measure organic molecules, with Hydrogen nucleus quantification (H qNMR) emerging as the primary method for assessing chemical purity.
  • A collaborative study involving 13 labs was conducted to validate the H qNMR method, measuring the purity of three samples certified by conventional methods.
  • Results showed that H qNMR measurements matched reference values closely, demonstrating its reliability and accuracy comparable to traditional measurement techniques.
View Article and Find Full Text PDF

Nuclear Magnetic Resonance (NMR) is an analytical technique extensively used in almost every chemical laboratory for structural identification. This technique provides statistically equivalent signals in spite of using spectrometer with different hardware features and is successfully used for the traceability and quantification of analytes in food samples. Nevertheless, to date only a few internationally agreed guidelines have been reported on the use of NMR for quantitative analysis.

View Article and Find Full Text PDF

Herein we describe for the first time a practical analytical method for determining the enantio-purity of L-α-glycerophosphocholine (L-α-GPC) by chiral derivatization. The use of a suitable chiral boronic acid allowed the formation of a mixture of two diastereomeric boronate esters whose ratio, carefully analyzed by HNMR spectroscopy, reflects L-α-GPC enantiomeric excesses. The determination of the enantiopurity of L-α-GPC furnishes convincing correlations with its manufacturing process.

View Article and Find Full Text PDF

This paper introduces an H NMR method to identify individual divalent metal cations Be , Mg , Ca , Sr , Zn , Cd , Hg , Sn , and Pb in aqueous salt solutions through their unique signal shift and coupling after complexation with the salt of ethylenediaminetetraacetic acid (EDTA). Furthermore, quantitative determination applied for the divalent metal cations Ca , Mg , Hg , Sn , Pb , and Zn (limit of quantification: 5-22 μg/ml) can be achieved using an excess of EDTA with aqueous model salt solutions. An internal standard is not required because a known excess of EDTA is added and the remaining free EDTA can be used to recalculate the quantity of chelated metal cations.

View Article and Find Full Text PDF

The aim of this research was to investigate the effect of herring roe phospholipids (PLs) on the oxidative stability of cod liver oil during storage. The effect of PLs on the oxidative stability of cod liver oil was assessed in terms of peroxide value, free fatty acids, secondary oxidation products and pyrrolisation. The results show that the PV was lower in cod liver oil containing PLs (P < 0.

View Article and Find Full Text PDF

The quantification of a drug, its impurities, and e.g. components of a mixture has become routine in NMR laboratories and many applications have been described in the literature.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

l-ascorbic acid 2-phosphate magnesium (APMg) salt is a vitamin C derivative frequently used in cell culture media for research purposes. It is also used as a raw material in the GMP-manufacturing of gene-, cell- and tissue advanced therapy medicinal products (ATMPs). However, quality methods are currently lacking.

View Article and Find Full Text PDF

Fatty acid conjugates of hydroxy-metabolites of tetrahydrocannabinol (THC) or cannabinol have already been reported as metabolites in rats. In the herein presented investigation, palmitic acid esters of THC and its primary metabolite 11-hydroxy-delta9-tetrahydrocannabinol (11-OH-THC) were synthesized using esterification with palmitic acid chloride. Structural elucidation of the products was conducted using nuclear magnetic resonance spectroscopy (NMR) and liquid chromatography coupled to quadrupole time of flight mass spectrometry (LC-QToF-MS).

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

Human milk oligosaccharides (HMO) are the third most abundant solid component of human milk. It is likely that they are responsible for at least some of the benefits experienced by breast-fed infants. Until recently HMO were absent from infant formula, but 2'-fucosyllactose (2'-FL) and lacto-N-neoteraose (LNnT) have recently become available as ingredients.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF