The Untargeted Capability of NMR Recognizes Adulterated Natural Products

Curcuma longa (turmeric) has a long ethnomedical background for common ailments, and Dietary Supplements (DS) labelled as “Curcumin” (CDS) are a highly visible portion of today’s selfmedication market. Due to cost pressure, these CDS products are affected by economically motivated adulteration with synthetic curcumin and are associated with unexpected toxicological issues due to “residual” impurities. Using a combination of targeted and untargeted (phyto)chemical analysis, this study investigated the botanical integrity of two commercial “turmeric” CDS with vitamin and other additives that were associated with reported clinical cases of hepatotoxicity. Analyzing multi-solvent extracts of the CDS by 100% quantitative 1H NMR (qHNMR), alone and in combination with countercurrent separation (CCS), provided chemical fingerprints that allowed both the targeted identification and quantification of declared components and the untargeted recognition of adulteration. While confirming the presence of curcumin as a major constituent, the universal detection capability of NMR identified significant residual impurities. While the loss free nature of CCS captured a wide polarity range of declared and unwanted chemical components and increased dynamic range, (q)HNMR determined their mass proportions and chemical constitutions. The results demonstrate that NMR can recognize undeclared constituents even if they represent a relatively minor gap in the mass balance of a DS product. The chemical information associated with the missing 4.8% and 7.4% (m/m) in the two commercial samples, exhibiting an otherwise adequate curcumin content of 95.2% and 92.6%, pointed to a product integrity issue and adulteration with undeclared synthetic curcumin. Impurities from synthesis are most plausibly the cause of the observed adverse clinical effects. The study exemplifies how the simultaneously targeted and untargeted analytical principle of 100% qHNMR method, performed with entry-level instrumentation (400 MHz), can enhance the safety of DS by identifying adulterated, non-natural “natural” products<br>

The Untargeted Capability of NMR Recognizes Adulterated Natural Products

Curcuma longa (turmeric) has a long ethnomedical background for common ailments, and Dietary Supplements (DS) labelled as “Curcumin” (CDS) are a highly visible portion of today’s selfmedication market. Due to cost pressure, these CDS products are affected by economically motivated adulteration with synthetic curcumin and are associated with unexpected toxicological issues due to “residual” impurities. Using a combination of targeted and untargeted (phyto)chemical analysis, this study investigated the botanical integrity of two commercial “turmeric” CDS with vitamin and other additives that were associated with reported clinical cases of hepatotoxicity. Analyzing multi-solvent extracts of the CDS by 100% quantitative 1H NMR (qHNMR), alone and in combination with countercurrent separation (CCS), provided chemical fingerprints that allowed both the targeted identification and quantification of declared components and the untargeted recognition of adulteration. While confirming the presence of curcumin as a major constituent, the universal detection capability of NMR identified significant residual impurities. While the loss free nature of CCS captured a wide polarity range of declared and unwanted chemical components and increased dynamic range, (q)HNMR determined their mass proportions and chemical constitutions. The results demonstrate that NMR can recognize undeclared constituents even if they represent a relatively minor gap in the mass balance of a DS product. The chemical information associated with the missing 4.8% and 7.4% (m/m) in the two commercial samples, exhibiting an otherwise adequate curcumin content of 95.2% and 92.6%, pointed to a product integrity issue and adulteration with undeclared synthetic curcumin. Impurities from synthesis are most plausibly the cause of the observed adverse clinical effects. The study exemplifies how the simultaneously targeted and untargeted analytical principle of 100% qHNMR method, performed with entry-level instrumentation (400 MHz), can enhance the safety of DS by identifying adulterated, non-natural “natural” products<br>

Влияние неконтролируемых примесей на спектр поглощения лазерного кристалла NaGd(WO-=SUB=-4-=/SUB=-)-=SUB=-2-=/SUB=-

Three NaGd(WO4)2 single crystals have been grown by Czochralski technique using the initial chemicals with different purity. Impurity concentrations were determined by the inductively coupled plasma mass-spectrometry. The optical absorption spectra of the crystals were measured and the influence of residual impurities' contents on optical properties and coloration of the crystals was determined. It was demonstrated that the green coloration which is sometimes observed for NaGd(WO4)2 crystals results from the presence of residual impurities of d-elements, for which the cromium impurity is the most important

CHANGES IN PHYSICAL PROPERTIES OF SUPER LONG CARBON NANOTUBES AFTER DIFFERENT METHODS OF PURIFICATION

The results of carbon nanotubes purification with various methods are presented. Methods providing residual impurities content less than 1% were revealed. Carbon nanotubes were investigated by Raman spectroscopy, TEM, SEM and TGA. Their electrical conductivity was measured as well.

Free charge localization and effective dielectric permittivity in oxides

This review will deal with several types of free charge localization in oxides and their consequences on the effective dielectric spectra of such materials. The first one is the polaronic localization at the unit cell scale on residual impurities in ferroelectric networks. The second one is the collective localization of free charge at macroscopic interfaces like surfaces, electrodes and grain boundaries in ceramics. Polarons have been observed in many oxide perovskites mostly when cations having several stable electronic configurations are present. In manganites, the density of such polarons is so high as to drive a net lattice of interacting polarons. On the other hand, in ferroelectric materials like BaTiO3 and LiNbO3, the density of polarons is usually very small but they can influence strongly the macroscopic conductivity. The contribution of such polarons to the dielectric spectra of ferroelectric materials is described. Even residual impurities as for example Iron can induce well-defined anomalies at very low temperatures. This is mostly resulting from the interaction between localized polarons and the highly polarizable ferroelectric network in which they are embedded. The case of such residual polarons in SrTiO3 will be described in more detail, emphasizing the quantum polaron state at liquid helium temperatures. Recently, several nonferroelectric oxides have been shown to display giant effective dielectric permittivity. It is first shown that the frequency/temperature behavior of such parameters is very similar in very different compounds (donor-doped BaTiO3, CaCu3Ti4O12, LuFe2O4, Li-doped NiO, etc.). This similarity calls for a common origin of the giant dielectric permittivity in these compounds. A space charge localization at macroscopic interfaces can be the key for such extremely high dielectric permittivity.