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Talanta Jun 2015To counter the growth of herbal medicines adulterated with pharmaceuticals crossing borders, rapid, inexpensive and non-destructive analytical techniques, that can...
To counter the growth of herbal medicines adulterated with pharmaceuticals crossing borders, rapid, inexpensive and non-destructive analytical techniques, that can handle complex matrices, are required. Since mid-infrared (MIR), near infrared (NIR) and Raman spectroscopic techniques meet these criteria, their performance in identifying adulterants in seized weightloss herbal medicines is definitively determined. Initially a validated high pressure liquid chromatography methodology was used for reference identification and quantification of the adulterants sibutramine H2O·HCl, fenfluramine HCl and phenolphthalein. Of 38 products, only sibutramine and phenolphthalein were detected by HPLC. The spectroscopic measurements showed Raman was ill-suited due to sample burning and emission while NIR lacked adulterant selectivity. Conversely, MIR demonstrated apt identification performance, which manifested as spectrally meaningful separation based on the presence and type of adulterant during principal component analysis (test set validated). Partial least squares regression models were constructed from the MIR training sets for sibutramine and phenolphthalein - both models fitted the training set data well. Average test set prediction errors were 0.8% for sibutramine and 2.2% for phenolphthalein over the respective concentration ranges of 1.7-11.7% and 0.9-34.4%. MIR is apposite for the screening of anorectic and laxative adulterants and is the most viable technique for wider adulterant screening in herbal medicines.
Topics: Cyclobutanes; Dietary Supplements; Drug Contamination; Herbal Medicine; Humans; Phenolphthalein; Plants, Medicinal; Principal Component Analysis; Spectrophotometry, Infrared; Spectrum Analysis, Raman; Vibration
PubMed: 25863375
DOI: 10.1016/j.talanta.2015.02.016 -
Carbohydrate Polymers Jan 2016Cellulose was cross-linked with epichlorohydrin (EP) at variable levels (CLE-0.5, CLE-2 and CLE-4), where CLE-i denotes the cellulose to EP mole ratios. The cross-linked...
Cellulose was cross-linked with epichlorohydrin (EP) at variable levels (CLE-0.5, CLE-2 and CLE-4), where CLE-i denotes the cellulose to EP mole ratios. The cross-linked products were characterized by TGA and FT-IR spectroscopy, pH at the point of zero charge (pHpzc), water swelling, and dye-adsorption methods employing two types of dyes [phenolphthalein (phth) and p-nitrophenol (PNP)]. The characterization methods provide evidence of cross-linking of cellulose in accordance with variations in surface area, PZC, available surface hydroxyl groups, and thermal stability when compared against pristine cellulose. The pHpzc of the sorbent materials was ∼ 6.5 indicating a negative surface charge occurs above pHpzc. The cross-linked polymers possess greater swelling properties relative to pristine cellulose. Detailed adsorption studies were carried out at pH 9 for cellulose and CLE-i with five types single component carboxylate anions [2-hexyldecanoic acid (S1), trans-4-pentylcyclohexanecarboxylic acid (S2), 2-dicyclohexylacetic acid (S3), adamantane carboxylic acid (S4), and cyclohexane carboxylic acid (S5)] at 295 K. The uptake properties of PNP with cellulose and CLE-i were also compared at pH 5 and 9, respectively. CLE-2 had the highest uptake of PNP (Qm=1.22 × 10(-1)mmol/g, pH 9) and S1 (Qm=4.27 mg/g) while cellulose and CLE-4 had the strongest binding affinity (1.43 L/mmol and 5.90 × 10(-2)L/mg), respectively. Uptake of PNP by CLE-0.5 at pH 5 (Q m=5.30 × 10(-2)mmol/g) was higher than uptake at pH 9 (Qm=3.11 × 10(-2)mmol/g). Sorption of CLE-4 with S1, S2 and S3 showed that relative uptake of the surrogates had the following order: S3>S2>S1, where S2 had the strongest binding affinity to CLE-i. CLE-2 had the highest sorption capacity towards Si in an equimolar mixture with evidence of molecular selective uptake. At pH 9, low uptake was mainly related to electrostatic repulsion between the negatively charged sorbent surface and the carboxylate head groups of Si.
Topics: Adsorption; Cellulose; Color; Epichlorohydrin; Models, Molecular; Molecular Conformation; Phenolphthalein; Polymers; Solutions; Surface Properties; Water
PubMed: 26572363
DOI: 10.1016/j.carbpol.2015.09.032 -
Biomedicines Sep 2023Dental composites, through their structural diversity, represent the biomaterials frequently used in dental reconstructive therapy. The aim of our study was to observe...
Dental composites, through their structural diversity, represent the biomaterials frequently used in dental reconstructive therapy. The aim of our study was to observe the influence of different beverage environment conditions on seven types of obturation dental materials with different compositions. Our research focused on the surface modification analysis of the materials after the immersion in the different beverages; in this regard, we used the EDAX technique correlated with the energy-dispersive X-ray fluorescence (XRF). The pH of the drinks and that of the simulated saliva solution were determined by the titrimetric method, a sodium hydroxide solution 0.1 mol/dm was prepared and used for the titration. An amount of 5 mL of each analyzed solution was added to 15 mL of distilled water to obtain a dilution, to which 3 drops of phenolphthalein (as a color indicator-Phenolphthalein, 3,3-Bis(4-hydroxyphenyl)-1(3H)-isobenzofuranone, CHO Mw: 318.32, purchased from Merck) were added for each analysis. For each solution, the experiment was repeated three times in order to obtain accurate results. The results of our study materialized into a real plea for modifying the patients' behavior in terms of diet and preferences for acidic drinks, so that their quality-of-life valence can be improved by keeping the composite materials in a long-term unalterable state on the one hand; on the other hand, systemic damage can be prevented as well.
PubMed: 37761013
DOI: 10.3390/biomedicines11092571 -
Membranes Jun 2021A class of phenolphthalein anilide (PA)-based poly(ether sulfone) multiblock copolymers containing pendant quaternary ammonium (QA) and imidazolium (IM) groups were...
Phenolphthalein Anilide Based Poly(Ether Sulfone) Block Copolymers Containing Quaternary Ammonium and Imidazolium Cations: Anion Exchange Membrane Materials for Microbial Fuel Cell.
A class of phenolphthalein anilide (PA)-based poly(ether sulfone) multiblock copolymers containing pendant quaternary ammonium (QA) and imidazolium (IM) groups were synthesized and evaluated as anion exchange membrane (AEM) materials. The AEMs were flexible and mechanically strong with good thermal stability. The ionomeric multiblock copolymer AEMs exhibited well-defined hydrophobic/hydrophilic phase-separated morphology in small-angle X-ray scattering and atomic force microscopy. The distinct nanophase separated membrane morphology in the AEMs resulted in higher conductivity (IECw = 1.3-1.5 mequiv./g, σ(OH) = 30-38 mS/cm at 20 °C), lower water uptake and swelling. Finally, the membranes were compared in terms of microbial fuel cell performances with the commercial cation and anion exchange membranes. The membranes showed a maximum power density of ~310 mW/m (at 0.82 A/m); 1.7 and 2.8 times higher than the Nafion 117 and FAB-PK-130 membranes, respectively. These results demonstrated that the synthesized AEMs were superior to Nafion 117 and FAB-PK-130 membranes.
PubMed: 34203084
DOI: 10.3390/membranes11060454 -
Drug Testing and Analysis Feb 2017Herbal medicines and food supplements intended as slimming aids are increasingly gaining popularity worldwide, especially for treating obesity. In this study, an...
Herbal medicines and food supplements intended as slimming aids are increasingly gaining popularity worldwide, especially for treating obesity. In this study, an ultra-performance liquid chromatography coupled to photodiode array detection (UPLC-PDA) and an ultra-performance liquid chromatography mass spectrometry (UPLC-MS) method were developed to analyze 92 slimming aids (confiscated by customs), aimed at acquiring highly informative fingerprints. Three types of fingerprints were acquired (PDA, Total Ion Chromatograms (TIC), and MS fingerprints) which were used in the chemometric data analysis. Both unsupervised (i.e., Hierarchical Cluster Analysis (HCA)) and supervised techniques (i.e., Classification and Regression Tree (CART) and Partial Least Squares - Discriminant Analysis (PLS-DA)) were applied. The aim was to perform an in-depth study of the samples, thereby exploring potential patterns present in the data. HCA was able to generate a clustering which was mainly defined by chemical compounds detected in the samples, i.e., sibutramine, phenolphthalein and amfepramone. PLS-DA generated the best diagnostic models for both PDA and TIC fingerprints, characterized by correct classification rates of external validation of 85% and 80%, respectively. For the MS fingerprints, the best model was obtained by CART (65% correct classification rate of external validation). Despite a lower correct classification rate, exploration of the concerned misclassifications revealed that the MS fingerprints proved to be superior since even very low concentrations of sibutramine could be detected. This study shows that reliable chemometric models can be obtained, based on the presence of prohibited chemical substances, which allow high-throughput data analysis of such samples. Moreover, they generate a prime notion of potential threat to a patient's health posed by these kinds of slimming aids. Copyright © 2016 John Wiley & Sons, Ltd.
Topics: Anti-Obesity Agents; Chromatography, High Pressure Liquid; Cluster Analysis; Discriminant Analysis; Least-Squares Analysis; Mass Spectrometry; Principal Component Analysis
PubMed: 27006262
DOI: 10.1002/dta.1964 -
Carbohydrate Polymers Jan 2023Nowadays, supramolecular hydrogels have gained special importance and development of versatile approaches for their preparation as well as their new facile...
Nowadays, supramolecular hydrogels have gained special importance and development of versatile approaches for their preparation as well as their new facile characterization strategies has elicited tremendous scientific interest. Herein, we demonstrate that modified cellulose nanowhisker with gallic acid pendant groups (CNW-GA) could effectively bind with CNW grafted with β-Cyclodextrin (CNW-g-β-CD) through HG interaction to form fully biocompatible and low-cost supramolecular hydrogel. Also, we reported an easy and efficient colorimetric characterization method for confirming HG complexation using naked eye. The possibility of this characterization strategy evaluated both experimentally and theoretically using DFT method. Also, phenolphthalein (PP) was used for visual detection of HG complexation. Interestingly, PP undergoes a rearrangement in its structure in presence of CNW-g-β-CD because of HG complexation that turns the purple molecule into a colorless compound in alkaline condition. Addition of CNW-GA to the resulting colorless solution turned the color to purple again which easily confirmed HG formation.
PubMed: 36876823
DOI: 10.1016/j.carbpol.2022.120222 -
Mikrochimica Acta Aug 2019A colorimetric test is described for the rapid detection of Staphylococcus aureus (SA). Gold nanorods (AuNRs) are first labeled with urease and yolk immunoglobulin...
Colorimetric detection of Staphylococcus aureus using gold nanorods labeled with yolk immunoglobulin and urease, magnetic beads, and a phenolphthalein impregnated test paper.
A colorimetric test is described for the rapid detection of Staphylococcus aureus (SA). Gold nanorods (AuNRs) are first labeled with urease and yolk immunoglobulin (IgY). This probe can specifically bind SA. In the next step, nonspecific magnetic beads and sample are added. This leads to the formation of the AuNR-IgY-SA-nMB immunocomplex which is then magnetically separated. Finally, a solution of urea is added to the supernatant. Ureases catalyzes the decomposition of urea which results in an increase in the pH value. The increase in the pH value is detected by using a phenolphthalein test paper which undergoes a color change from white to pink. The analytical process can be completed within 20 min. The method is highly specific and can detect as little as 476 cfu·mL. It was verified by analyzing contaminated Chinese cabbage and beef samples, and 1000 cfu·mL of SA were accurately detected. Graphical abstract Schematic representation of a colorimetric method for the detection of Staphylococcus aureus based on the immunocomplex formed from dual-labeled gold nanorod (AuNR) probe, bacteria and non-specific magnetic bead (nMB). This method can be completed within 20 min.
Topics: Biosensing Techniques; Colorimetry; Egg Yolk; Gold; Immunoglobulins; Magnets; Microspheres; Nanotubes; Paper; Phenolphthalein; Staphylococcus aureus; Urease
PubMed: 31396712
DOI: 10.1007/s00604-019-3722-0 -
Molecules (Basel, Switzerland) Mar 2020The recent introduction of compact or low-field (LF) NMR spectrometers that use permanent magnets, giving rise to proton (H) NMR frequencies between 40 and 80 MHz, have...
The recent introduction of compact or low-field (LF) NMR spectrometers that use permanent magnets, giving rise to proton (H) NMR frequencies between 40 and 80 MHz, have opened up new areas of application. The two main limitations of the technique are its insensitivity and poor spectral resolution. However, this study demonstrates that the chemometric treatment of LF H NMR spectral data is suitable for unveiling medicines as adulterants of slimming dietary supplements (DS). To this aim, 66 DS were analyzed with LF H NMR after quick and easy sample preparation. A first PLS-DA model built with the LF H NMR spectra from forty DS belonging to two classes of weight-loss DS (non-adulterated, and sibutramine or phenolphthalein-adulterated) led to the classification of 13 newly purchased test samples as natural, adulterated or borderline. This classification was further refined when the model was made from the same 40 DS now considered as representing three classes of DS (non-adulterated, sibutramine-adulterated, and phenolphthalein-adulterated). The adulterant (sibutramine or phenolphthalein) was correctly predicted as confirmed by the examination of the H NMR spectra. A limitation of the chemometric approach is discussed with the example of two atypical weight-loss DS containing fluoxetine or raspberry ketone.
Topics: Dietary Supplements; Drug Contamination; Proton Magnetic Resonance Spectroscopy
PubMed: 32155779
DOI: 10.3390/molecules25051193 -
Polymers May 2021Polyetheretherketone (PEEK)/polyethersulfone (PES) blends are initially not miscible, except when the blends are prepared by solvent mixing. We propose a route to...
Polyetheretherketone (PEEK)/polyethersulfone (PES) blends are initially not miscible, except when the blends are prepared by solvent mixing. We propose a route to elaborate PEEK/PES blends with partial miscibility by melt mixing at 375 °C with phenolphthalein. The miscibility of blends has been examined using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMTA). When adding phenolphthalein to PEEK/PES blends, the glass transitions are shifted inward as an indication of miscibility. We suggest that phenolphthalein acts as a compatibilizer by creating cardo side groups on PEEK and PES chains by nucleophilic substitution in the melted state, although this condensation reaction was reported only in the solvent until now. In addition, phenolphthalein acts as a plasticizer for PES by decreasing its glass transition. As a consequence, the PEEK phase is softened which favors the crystallization as the increase of crystalline rate. Due to aromatic moieties in phenolphthalein, the storage modulus of blends in the glassy region is kept identical to pure PEEK. The morphological analysis by SEM pictures displays nano- to microsized PES spherical domains in the PEEK matrix with improved PEEK/PES interfacial adhesion.
PubMed: 34062773
DOI: 10.3390/polym13091466 -
Turkish Journal of Chemistry 2021This study reports a detailed analysis of an electrode material containing poly(phenolphthalein), carbon nanotubes and gold nanoparticles which shows superior catalytic...
This study reports a detailed analysis of an electrode material containing poly(phenolphthalein), carbon nanotubes and gold nanoparticles which shows superior catalytic effect towards to hydrazine oxidation in Britton-Robinson buffer (pH 10.0). Glassy carbon electrode was modified by electropolymerization of phenolphthalein (PP) monomer (poly(PP)/GCE) and the multiwalled carbon nanotubes (MWCNTs) was dropped on the surface. This modified surface was electrodeposited with gold nanoparticles (AuNPs/CNT/poly(PP)/GCE). The fabricated electrode was analysed the determination of hydrazine using cyclic voltammetry, linear sweep voltammetry and amperometry. The peak potential of hydrazine oxidation on bare GCE, poly(PP)/GCE, CNT/GCE, CNT/poly(PP)/GCE, and AuNPs/CNT/poly(PP)/GCE were observed at 596 mV, 342 mV, 320 mV, 313 mV, and 27 mV, respectively. A shift in the overpotential to more negative direction and an enhancement in the peak current indicated that the AuNPs/CNT/poly(PP)/GC electrode presented an efficient electrocatalytic activity toward oxidation of hydrazine. Modified electrodes were characterized with High-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). Amperometric current responses in the low hydrazine concentration range of 0.25-13 µM at the AuNPs/CNT/poly(PP)/GCE. The limit of detection (LOD) value was obtained to be 0.083 µM. A modified electrode was applied to naturel samples for hydrazine determination.
PubMed: 33679162
DOI: 10.3906/kim-2009-12