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Mecozzi M.,European Commission - Joint Research Center Ispra | Pietroletti M.,European Commission - Joint Research Center Ispra | Monakhova Y.B.,Spectral Service AG | Monakhova Y.B.,Chernyshevsky Saratov State University
Marine Pollution Bulletin | Year: 2016

We inserted 190 FTIR spectra of plastic samples in a digital database and submitted it to Independent Component Analysis (ICA) to extract the "pure" plastic polymers present. These identified plastics were polypropylene (PP), high density polyethylene (HDPE), low density polyethylene (LDPE), high density polyethylene terephthalate (HDPET), low density polyethylene terephthalate (LDPET), polystyrene (PS), Nylon (NL), polyethylene oxide (OPE), and Teflon (TEF) and they were used to establish the similarity with unknown plastics using the correlation coefficient (r), and the crosscorrelation function (CC). For samples with r <. 0.8 we determined the Mahalanobis Distance (MD) as additional tool of identification. For instance, for the four plastic fragments found in the Carretta carretta, one plastic sample was assigned to OPE due to its r = 0.87; for all the other three plastic samples, due to the r values ranging between 0.83 and0.70, the support of MD suggested LDPET and OPE as co-polymer constituents. © 2016 Elsevier Ltd.


Lu F.S.H.,Technical University of Denmark | Nielsen N.S.,Technical University of Denmark | Baron C.P.,Technical University of Denmark | Diehl B.W.K.,Spectral Service AG | Jacobsen C.,Technical University of Denmark
Journal of Agricultural and Food Chemistry | Year: 2012

The objective of this study was to investigate the oxidative stability of dispersions prepared from different levels of purified marine phospholipid (PL) obtained by acetone precipitation, with particular focus on the interaction between α-tocopherol and PL in dispersions. This also included the investigation of nonenzymatic browning in purified marine PL dispersions. Dispersions were prepared by high-pressure homogenizer. The oxidative and hydrolytic stabilities of dispersions were investigated by determination of hydroperoxides, secondary volatile oxidation products, and free fatty acids, respectively, during 32 days of storage at 2 °C. Nonenzymatic browning was investigated through measurement of Strecker aldehydes, color changes, and pyrrole content. Dispersions containing α-tocopherol or higher levels of purified marine PL showed a lower increment of volatiles after 32 days storage. The results suggested that tocopherol is an efficient antioxidant in PL dispersions or that the presence of α-tocopherol and pyrroles may be the main reason for the high oxidative stability of purified marine PL dispersions. © 2012 American Chemical Society.


Lu F.S.H.,Technical University of Denmark | Nielsen N.S.,Technical University of Denmark | Baron C.P.,Technical University of Denmark | Diehl B.W.K.,Spectral Service AG | Jacobsen C.,Technical University of Denmark
Food Chemistry | Year: 2013

The main objective of this study was to investigate the oxidative stability and non-enzymatic browning reactions of marine PL in the presence or in the absence of primary amine group from aminophosphol-ipids and amino acids. Marine phospholipids liposomal dispersions were prepared from two authentic standards (phosphatidylcholine and phosphatidylethanolamine) and two purified PL from marine sources with and without addition of amino acids (leucine, methionine and lysine). Samples were incubated at 60°C for 0, 2,4 and 6 days. Non-enzymatic browning reactions were investigated through measurement of (i) Strecker derived volatiles, (ii) yellowness index (YI), (iii) hydrophobic and (iv) hydrophilic pyrroles content. The oxidative stability of the samples was assessed through measurement of secondary lipid derived volatile oxidation products. The result showed that the presence of PE and amino acids caused the formation of pyrroles, generated Strecker derived volatiles, decreased the YI development and lowered lipid oxidation. The lower degree of lipid oxidation in liposomal dispersions containing amino acids might be attributed to antioxidative properties of pyrroles or amino acids. © 2013 Elsevier Ltd. All rights reserved.


Monakhova Y.B.,Spectral Service AG | Monakhova Y.B.,Chernyshevsky Saratov State University | Diehl B.W.K.,Spectral Service AG
Journal of Pharmaceutical and Biomedical Analysis | Year: 2015

1H NMR spectroscopy was used to distinguish pure porcine heparin and porcine heparin blended with bovine species and to quantify the degree of such adulteration. For multivariate modelling several statistical methods such as partial least squares regression (PLS), ridge regression (RR), stepwise regression with variable selection (SR), stepwise principal component regression (SPCR) were utilized for modeling NMR data of in-house prepared blends (n=80). The models were exhaustively validated using independent test and prediction sets. PLS and RR showed the best performance for estimating heparin falsification regarding its animal origin with the limit of detection (LOD) and root mean square error of validation (RMSEV) below 2% w/w and 1% w/w, respectively. Reproducibility expressed in coefficients of variation was estimated to be below 10% starting from approximately 5% w/w of bovine adulteration. Acceptable calibration model was obtained by SPCR, by its application range was limited, whereas SR is least recommended for heparin matrix. The developed method was found to be applicable also to heparinoid matrix (not purified heparin). In this case root mean square of prediction (RMSEP) and LOD were approximately 7% w/w and 8% w/w, respectively. The simple and cheap NMR method is recommended for screening of heparin animal origin in parallel with official NMR test of heparin authenticity and purity. © 2015 Elsevier B.V..


Monakhova Y.B.,Spectral Service AG | Monakhova Y.B.,Chernyshevsky Saratov State University | Diehl B.W.K.,Spectral Service AG
JAOCS, Journal of the American Oil Chemists' Society | Year: 2016

NMR spectroscopy was used to distinguish pure sunflower lecithin from that blended with soy species, and to quantify the degree of such adulteration. Sample preparation included liquid extraction of lecithin blends and measurement of polar and non-polar fractions using 31P and 1H NMR spectrometry. Several phospholipid species, linolenic acid and stachyose were found to be characteristic for sunflower lecithin authentication. For quantitative analysis, partial least squares regression (PLS) was utilized for modeling NMR data of authentic lecithin samples and in-house prepared blends (n = 80). The models based on phospholipid, fatty acid and saccharide distributions were validated using independent test sets. PLS based on saccharide composition is able to estimate lecithin falsification regarding its vegetable origin with the sensitivity and root mean square error of validation below 1 % w/w and 3.5 % w/w, respectively. Prediction error was improved by modeling the whole lecithin profile (phospholipids, fatty acids, and saccharides). Repeatability and precision expressed in coefficients of variations was estimated to be below 8 %. The developed approach allowed the evaluation of the composition of lecithin blends of unknown soy and sunflower content on the basis of multiple chemical components. © 2015 AOCS.


Monakhova Y.B.,Spectral Service AG | Monakhova Y.B.,Chernyshevsky Saratov State University | Diehl B.W.K.,Spectral Service AG
Analytical Methods | Year: 2016

A methodology utilizing 1H NMR spectroscopy has been developed to measure the concentration of hydrogen peroxide in hair sprays, nail treatments, hydrogen peroxide solutions for disinfection and chemical reagents. For sample preparation, only a dilution with DMSO-d6 to prevent coalescence of OH peaks and addition of an internal standard are required. The peroxide content is quantified by a distinct peak at δ 10.2 ppm against the signal of the methyl group of dimethylformamide (δ 2.9 ppm). The limit of detection of the developed methodology varied between 10-4% w/w for chemical reagent and disinfection products and 10-2% w/w for hair sprays and is sufficient to determine concentrations of hydrogen peroxide up to the maximum allowed limit. The coefficients of variation for intraday reproducibility do not exceed 0.9%. The 1H NMR spectra showed linearity for 10-100 μL sample volume (R2 = 0.9958). Recovery values varied in the range of 103-111% (106% on average). The stability of the analytical system was proved for seven days. The methodology was successfully applied to the analysis of nine authentic products. Furthermore, the analysis of signal positions and diffusion constants with varying peroxide concentrations (up to 30 w/w%) indicated the presence of H2O2-(H2O)6 and DMF-(H2O)3 intermolecular complexes in the analytical system. © 2016 The Royal Society of Chemistry.


Formes A.,Spectral Service AG | Diehl B.,Spectral Service AG
Journal of Pharmaceutical and Biomedical Analysis | Year: 2014

Against the background of the scandal about low-grade silicone breast implants of the French manufacturer Poly Implant Prothese (PIP), several types of implants were examined using 1H NMR spectroscopy. The intention was to classify an implant according to its silicone structure. Therefore, the certificated raw material of the American silicone producer Nusil Technology was analyzed and used as a reference. The list of tested implants consists of implants by PFM medical, PIP, Silimed, Rofil, Eurosilicone, Mentor, Perouse Plastie, Polytech, Nagor, CUI, and McGhan. In the 1H NMR spectrum the signal of the vinyl group, which is used to cross link silicone rubbers, is visible. It is possible to differentiate between silicones which have a vinyl terminated end group and silicones whose vinyl group is located within the chain of the polymer. The two different types of the vinyl group are one mean to classify the implants. Other categories besides the type of vinyl include the relative amount of the remaining vinyl in the implant and the chemical structure of the material used for the production of the envelope. With these characteristics the examined implants could be grouped into four types. © 2013 Elsevier B.V.


Zailer E.,Spectral Service AG | Diehl B.W.K.,Spectral Service AG
Journal of Pharmaceutical and Biomedical Analysis | Year: 2016

A rapid, accurate and specific proton nuclear magnetic resonance (1H NMR) spectroscopic method is developed to determine ethanol in blood, known as the blood alcohol concentration (BAC). The limits of detection and quantification are 0.02g/L and 0.07g/L, respectively. The 1H NMR spectra show linearity for whole blood and serum samples of a concentration range of 0.00-3.00g/L (R2>0.9995). The 1H NMR method is applied and validated for whole blood as the sample media. Real driving under influence case samples are analyzed with the reference enzyme-based alcohol dehydrogenase and headspace gas chromatography techniques by the Forensic Medicine in Bonn. The reference results are compared with the 1H NMR spectroscopic results. The validation and comparison indicate that 1H NMR is suitable for the quantification of BAC in whole blood. This technique has the advantages of automated analysis with good measurement precision and fast sample throughput. A drop of blood (V=20μL) is adequate for an analysis leading to a possible simplification of the sample collection. Due to the non-destructive method, follow-up examinations by 1H NMR spectroscopy or DNA determinations by different techniques (PCR, in situ hybridization) are possible in resolving legal disputes. © 2015 Elsevier B.V.


PubMed | Spectral Service AG
Type: Journal Article | Journal: Journal of the science of food and agriculture | Year: 2016

Due to possible falsification of sugar cane products with cheaper alternative (sugar beet) on the market, a simple analytical methodology needs to be developed to control the authenticity of sugar products.A direct (13) C nuclear magnetic resonance (NMR) method has been validated to differentiate between sucrose-based sugar products produced from sugar beet (C3 plant) and sugar cane (C4 plant). The method is based on calculating relative (13) C content of the C1, C2, C5, and the C1, C4, C5, C6 positions of the glycosyl and fructosyl moieties of the sucrose molecule, respectively. NMR acquisition parameters and data processing have been optimized to reach a high level of intraday and interday precision (<0.2%). Good linearity (R(2) =0.93) was obtained for the beet sugar-cane sugar blends containing from 0 to 100wt% of beet sugar. The method was applied to ten commercial sucrose-based sugar products of different botanical origin. Principal component analysis (PCA) was applied to the relative peak areas for replicate measurements to visualize the difference between studied products.The (13) C NMR method is a good alternative to complex isotope ratio mass spectrometry measurements for routine detection and semi-quantification of adulteration of commercial cane sugar (C4 plant) with less expensive beet sugar (C3 plant). 2015 Society of Chemical Industry.


PubMed | Spectral Service AG
Type: Journal Article | Journal: Journal of AOAC International | Year: 2016

Recent classification of Aloe vera whole-leaf extract by the International Agency for Research and Cancer as a possible carcinogen to humans as well as the continuous adulteration of A. veras authentic material have generated renewed interest in controlling A. vera. The existing NMR spectroscopic method for the analysis of A. vera, which is based on a routine developed at Spectral Service, was extended. Apart from aloverose, glucose, malic acid, lactic acid, citric acid, whole-leaf material (WLM), acetic acid, fumaric acid, sodium benzoate, and potassium sorbate, the quantification of Mg(2+), Ca(2+), and fructose is possible with the addition of a Cs-EDTA solution to sample. The proposed methodology was automated, which includes phasing, baseline-correction, deconvolution (based on the Lorentzian function), integration, quantification, and reporting. The NMR method was applied to 41 A. vera preparations in the form of liquid A. vera juice and solid A. vera powder. The advantages of the new NMR methodology over the previous method were discussed. Correlation between the new and standard NMR methodologies was significant for aloverose, glucose, malic acid, lactic acid, citric acid, and WLM (P < 0.0001, R(2) = 0.99). NMR was found to be suitable for the automated simultaneous quantitative determination of 13 parameters in A. vera.

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