TY - JOUR A1 - Adels, Klaudia A1 - Elbers, Gereon A1 - Diehl, Bernd A1 - Monakhova, Yulia T1 - Multicomponent analysis of dietary supplements containing glucosamine and chondroitin: comparative low- and high-field NMR spectroscopic study JF - Analytical Sciences N2 - 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. In the majority of cases, quantification results obtained on the low-field NMR spectrometer are similar to those obtained with high-field 500–600 MHz NMR devices. Validation results in terms of accuracy, precision, reproducibility, limit of detection and recovery demonstrated that the developed method is fit for purpose for the marketed products. The NMR method was extended to the analysis of methylsulfonylmethane, adulterant maltodextrin, acetate and inorganic ions. Low-field NMR can be a quicker and cheaper alternative to more expensive high-field NMR measurements for quality control of the investigated dietary supplements. High-field NMR instrumentation can be more favorable for samples with complex composition due to better resolution, simultaneously giving the possibility of analysis of inorganic species such as potassium and chloride. KW - Glucosamine KW - Chondroitin sulfate KW - Polysaccharides KW - Dietary supplements KW - High-field NMR Y1 - 2023 U6 - http://dx.doi.org/10.1007/s44211-023-00433-2 SN - 1348-2246 (Online) SN - 0910-6340 (Print) N1 - Corresponding author: Yulia Monakhova VL - 2023 PB - Springer Verlag CY - Cham ER - TY - JOUR A1 - Block, Franziska A1 - May, Alexander A1 - Wetzel, Katharina A1 - Adels, Klaudia A1 - Elbers, Gereon A1 - Schulze, Margit A1 - Monakhova, Yulia T1 - What is the best spectroscopic method for simultaneous analysis of organic acids and (poly)saccharides in biological matrices: Example of Aloe vera extracts? JF - Talanta Open N2 - Several species of (poly)saccharides and organic acids can be found often simultaneously in various biological matrices, e.g., fruits, plant materials, and biological fluids. The analysis of such matrices sometimes represents a challenging task. Using Aloe vera (A. vera) plant materials as an example, the performance of several spectro-scopic methods (80 MHz benchtop NMR, NIR, ATR-FTIR and UV–vis) for the simultaneous analysis of quality parameters of this plant material was compared. The determined parameters include (poly)saccharides such as aloverose, fructose and glucose as well as organic acids (malic, lactic, citric, isocitric, acetic, fumaric, benzoic and sorbic acids). 500 MHz NMR and high-performance liquid chromatography (HPLC) were used as the reference methods. UV–vis data can be used only for identification of added preservatives (benzoic and sorbic acids) and drying agent (maltodextrin) and semiquantitative analysis of malic acid. NIR and MIR spectroscopies combined with multivariate regression can deliver more informative overview of A. vera extracts being able to additionally quantify glucose, aloverose, citric, isocitric, malic, lactic acids and fructose. Low-field NMR measurements can be used for the quantification of aloverose, glucose, malic, lactic, acetic, and benzoic acids. The benchtop NMR method was successfully validated in terms of robustness, stability, precision, reproducibility and limit of detection (LOD) and quantification (LOQ), respectively. All spectroscopic techniques are useful for the screening of (poly)saccharides and organic acids in plant extracts and should be applied according to its availability as well as information and confidence required for the specific analytical goal. Benchtop NMR spectroscopy seems to be the most feasible solution for quality control of A. vera products. KW - Spectroscopy KW - (Poly)saccharides KW - Organic acids KW - Aloe vera KW - qNMR Y1 - 2023 U6 - http://dx.doi.org/10.1016/j.talo.2023.100220 SN - 2666-8319 VL - 7 IS - Art. No. 100220 SP - 1 EP - 9 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Druckenmüller, Katharina A1 - Günther, Klaus A1 - Elbers, Gereon T1 - Near-infrared spectroscopy (NIRS) as a tool to monitor exhaust air from poultry operations JF - Science of the Total Environment N2 - Intensive poultry operation systems emit a considerable volume of inorganic and organic matter in the surrounding environment. Monitoring cleaning properties of exhaust air cleaning systems and to detect small but significant changes in emission characteristics during a fattening cycle is important for both emission and fattening process control. In the present study, we evaluated the potential of near-infrared spectroscopy (NIRS) combined with chemometric techniques as a monitoring tool of exhaust air from poultry operation systems. To generate a high-quality data set for evaluation, the exhaust air of two poultry houses was sampled by applying state-of-the-art filter sampling protocols. The two stables were identical except for one crucial difference, the presence or absence of an exhaust air cleaning system. In total, twenty-one exhaust air samples were collected at the two sites to monitor spectral differences caused by the cleaning device, and to follow changes in exhaust air characteristics during a fattening period. The total dust load was analyzed by gravimetric determination and included as a response variable in multivariate data analysis. The filter samples were directly measured with NIR spectroscopy. Principal component analysis (PCA), linear discriminant analysis (LDA), and factor analysis (FA) were effective in classifying the NIR exhaust air spectra according to fattening day and origin. The results indicate that the dust load and the composition of exhaust air (inorganic or organic matter) substantially influence the NIR spectral patterns. In conclusion, NIR spectroscopy as a tool is a promising and very rapid way to detect differences between exhaust air samples based on still not clearly defined circumstances triggered during a fattening period and the availability of an exhaust air cleaning system. Y1 - 2018 U6 - http://dx.doi.org/10.1016/j.scitotenv.2018.02.072 SN - 0048-9697 VL - 630 SP - 536 EP - 543 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Elbers, Gereon T1 - Messung von Ruß in der Außenluft - Praktische Erfahrungen und Meßergebnisse aus NRW JF - Aktuelle Aufgaben der Messtechnik in der Luftreinhaltung : Kolloquium Heidelberg, 2. bis 4. Juni 1993 / Kommission Reinhaltung der Luft im VDI und DIN Y1 - 1993 SN - 3-18-091059-3 N1 - VDI-Berichte ; 1059 SP - 337 PB - VDI-Verl. CY - Düsseldorf ER - TY - BOOK A1 - Elbers, Gereon T1 - Entwicklung eines Schnellmessverfahrens zur Charakterisierung der Wirkung von Umweltschadstoffen auf Pflanzen mit der Nahinfrarot-Spektroskopie : Schlussbericht zum Forschungsvorhaben ; Vorhabensbezeichnung: Schnellmessverfahren zur Charakterisierung der Wirkung von Umweltschadstoffen ; Laufzeit des Vorhabens: 01.09.2002 bis 29.02.2004 ; Verlängerung der Laufzeit: 01.03.2004 bis 30.04.04 ; Berichtszeitraum: 01.09.2002 bis 30.04.2004 / Zuwendungsempfänger: FH-Aachen, Abt. Jülich, FB Chemie und Biotechnik. Gereon Elbers Y1 - 2004 N1 - Förderkennzeichen BMBF 1704502 ; weitere elektr. Ausgabe der TIB Hannover : http://edok01.tib.uni-hannover.de/edoks/e01fb05/485188317.pdf PB - Fachhochschule Aachen CY - Jülich ER - TY - JOUR A1 - Elbers, Gereon T1 - Identification of marker peptides in hair for discrimination with regard to species and breed / Koerner, Andrea ; Ring, Maike ; Fabry, Marlies ; Elbers, Gereon ; Moeller, Martin JF - Proceedings of the Aachen-Dresden International Textile Conference, 3rd, Aachen, Germany, Nov. 26-27, 2009 Y1 - 2009 N1 - Aachen-Dresden International Textile Conference ; (3 : ; 2009.11.26-27 : ; Aachen) PB - DWI CY - Aachen ER - TY - JOUR A1 - Elbers, Gereon A1 - Bauer, H. D. A1 - Buck, Manfred A1 - Dahmann, D. T1 - Rußmessungen am Arbeitsplatz und in der Außenluft - Vergleich zweier Meßmethoden / H.D. Bauer, M. Buck, D. Dahmann, G. Elbers, H.-H. Fricke JF - Staub, Reinhaltung der Luft : air quality control. 54 (1994) Y1 - 1994 SN - 0039-0771 SP - 55 ER - TY - JOUR A1 - Elbers, Gereon A1 - Behner, T. A1 - Remme, S. A1 - Prissok, F. T1 - Interstitial Metal Impurities as a Possible Cause of Enhanced Reactivities / T. Behner, G. Elbers, S. Remme, F. Prissok, P. Stegger, and G. Lehmann JF - Berichte der Bunsen-Gesellschaft : physical chemistry, chemical physics. 90 (1986) Y1 - 1986 SN - 0005-9021 SP - 698 ER - TY - JOUR A1 - Elbers, Gereon A1 - Buck, Manfred T1 - Soot Concentration in Ambient Air / M. Buck, G. Elbers JF - Erdöl & Kohle, Erdgas, Petrochemie : EKEP. 45 (1992) Y1 - 1992 SN - 0014-0058 SP - 219 ER - TY - JOUR A1 - Elbers, Gereon A1 - Gäb, Martina A1 - Hoffmann, Katharina A1 - Lobe, Melanie T1 - NIR-spectroscopic investigation of foliage of ozone-stressed Fagus sylvatica trees / Gäb, Martina ; Hoffmann, Katharina ; Lobe, Melanie ; Metzger, Rut ; Ooyen, Sven van ; Elbers, Gereon ; Köllner, Barbara JF - Journal of Forest Research. 11 (2006), H. 2 Y1 - 2006 SN - 1341-6979 SP - 69 EP - 75 ER -