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Molecules (Basel, Switzerland) Nov 2023Gemcitabine is a chemotherapeutic agent used to treat various malignancies, including breast and bladder cancer. In the current study, three innovative selective...
Gemcitabine is a chemotherapeutic agent used to treat various malignancies, including breast and bladder cancer. In the current study, three innovative selective gemcitabine hydrochloride sensors are developed using 4-tert-butylcalix-[8]-arene (sensor 1), β-cyclodextrin (sensor 2), and γ-cyclodextrin (sensor 3) as ionophores. The three sensors were prepared by incorporating the ionophores with -nitrophenyl octyl ether as plasticizer and potassium tetrakis(4-chlorophenyl) borate as ionic additive into a polyvinyl chloride polymer matrix. These sensors are considered environmentally friendly systems in the analytical research. The linear responses of gemcitabine hydrochloride were in the concentration range of 6.0 × 10 to 1.0 × 10 mol L and 9.0 × 10 to 1.0 × 10 mol L and 8.0 × 10 to 1.0 × 10 mol L for sensors 1, 2, and 3, respectively. Over the pH range of 6-9, fast-Nernst slopes of 52 ± 0.6, 56 ± 0.3, and 55 ± 0.8 mV/decade were found in the same order with correlation regressions of 0.998, 0.999, and 0.998, respectively. The lower limits of detection for the prepared sensors were 2.5 × 10, 2.2 × 10, and 2.7 × 10 mol L. The sensors showed high selectivity and sensitivity for gemcitabine. Validation of the sensors was carried out in accordance with the requirements established by the IUPAC, while being inexpensive and easy to use in drug formulation. A statistical analysis of the methods in comparison with the official method showed that there was no significant difference in accuracy or precision between them. It was shown that the new sensors could selectively and accurately find gemcitabine hydrochloride in bulk powder, pharmaceutical formulations, and quality control tests. The ionophore-based sensor shows several advantages over conventional PVC membrane sensor sensors regrading the lower limit of detection, and higher selectivity towards the target ion.
Topics: Drug Compounding; Gemcitabine; Ionophores; Antineoplastic Agents; Polymers; Potentiometry; Polyvinyl Chloride
PubMed: 38005274
DOI: 10.3390/molecules28227552 -
Rigorous pH measurement in non-aqueous solution: measurement method and reference values in ethanol.Analytical and Bioanalytical Chemistry Jan 2024The recently introduced unified pH ([Formula: see text]) concept enables rigorous pH measurements in non-aqueous and mixed media while at the same time maintaining...
The recently introduced unified pH ([Formula: see text]) concept enables rigorous pH measurements in non-aqueous and mixed media while at the same time maintaining comparability to the conventional aqueous pH scale. However, its practical application is hindered by a shortage of reference [Formula: see text] values. In order to improve this situation, the European Metrology Research Project (EMPIR) UnipHied ("Realisation of a UnipHied pH scale") launched an interlaboratory comparison among highly experienced electrochemistry expert laboratories to assign the first such reference [Formula: see text] values by adopting an extensive statistical treatment of the reported measurement data: to phosphate buffer in water-ethanol mixture (50 wt% of ethanol) and ammonium formate buffer in pure ethanol. Two different measurement setups - one capable of being easily adopted in industrial applications - have been used to demonstrate the robustness of [Formula: see text] measurement. This is an important step towards wider adoption of the [Formula: see text] concept in practice, like liquid chromatography, biofuels analysis and electrocatalysis.
PubMed: 38001374
DOI: 10.1007/s00216-023-05043-5 -
Membranes Nov 2023Recently, there has been rapid development of electrochemical sensors, and there have been numerous reports in the literature that describe new constructions with... (Review)
Review
Recently, there has been rapid development of electrochemical sensors, and there have been numerous reports in the literature that describe new constructions with improved performance parameters. Undoubtedly, this is due to the fact that those sensors are characterized by very good analytical parameters, and at the same time, they are cheap and easy to use, which distinguishes them from other analytical tools. One of the trends observed in their development is the search for new functional materials. This review focuses on potentiometric sensors designed with the use of various metal oxides. Metal oxides, because of their remarkable properties including high electrical capacity and mixed ion-electron conductivity, have found applications as both sensing layers (e.g., of screen-printing pH sensors) or solid-contact layers and paste components in solid-contact and paste-ion-selective electrodes. All the mentioned applications of metal oxides are described in the scope of the paper. This paper presents a survey on the use of metal oxides in the field of the potentiometry method as both single-component layers and as a component of hybrid materials. Metal oxides are allowed to obtain potentiometric sensors of all-solid-state construction characterized by remarkable analytical parameters. These new types of sensors exhibit properties that are competitive with those of the commonly used conventional electrodes. Different construction solutions and various metal oxides were compared in the scope of this review based on their analytical parameters.
PubMed: 37999362
DOI: 10.3390/membranes13110876 -
Analytica Chimica Acta Dec 2023Uranium is a toxic, heavy metal that can pose elevated health risks if leached into the environment. Uranium mobility is dependent on many factors, including speciation,...
Uranium is a toxic, heavy metal that can pose elevated health risks if leached into the environment. Uranium mobility is dependent on many factors, including speciation, solution pH, ligands in solution, and presence of surfaces. Surface adsorption is one phenomenon that inhibits uranium mobility in the environment and is studied as a naturally occurring phenomenon as well an intentional tool for environmental remediation. This work presents and validates a potentiometric, electrochemical technique for sensing uranium adsorption on and desorption from an electrochemically active surface solely through changes of the electrode potential. This novel electrochemical technique presents a new lens to study adsorption that complements external techniques (e.g., spectroscopy). Indication of adsorption and desorption via the electrochemical technique are gravimetrically validated using an electrochemical quartz crystal microbalance. This work contributes a unique, complementary technique that corroborates the adsorption of uranium on an electrode surface.
PubMed: 37996162
DOI: 10.1016/j.aca.2023.342003 -
Scientific Reports Nov 2023Analysis of drugs clinically and their identification in biological samples are of utmost importance in the process of therapeutic drug monitoring, also in...
Analysis of drugs clinically and their identification in biological samples are of utmost importance in the process of therapeutic drug monitoring, also in pharmacokinetic investigations and tracking of illicit medications. These investigations are carried out using a variety of analytical methods, including potentiometric electrodes. Potentiometric electrodes are a wonderful solution for researchers because they outperform other methods in terms of sustainability, greenness, and cost effectiveness. In the current study, ion-selective potentiometric sensors were assembled for the aim of quantification of the anticancer drug Letrozole (LTZ). The first step was fabrication of a conventional sensor based on the formation of stable host-guest inclusion complex between the cationic drug and 4-tert-butylcalix-8-arene (TBCAX-8). Two additional sensors were prepared through membrane modification with graphene nanocomposite (GNC) and polyaniline (PANI) nanoparticles. Linear responses of 1.00 × 10-1.00 × 10, 1.00 × 10-1.00 × 10 and 1.00 × 10-1.00 × 10 with sub-Nernstian slopes of 19.90, 20.10 and 20.30 mV/decade were obtained for TBCAX-8, GNC, and PANI sensors; respectively. The developed sensors were successful in determining the drug LTZ in bulk powder and dosage form. PANI modified sensor was used to determine LTZ in human plasma with recoveries ranging from 88.00 to 96.30%. IUPAC recommendations were followed during the evaluation of the electrical performance of the developed sensors. Experimental conditions as temperature and pH were studied and optimized. Analytical Eco-scale and Analytical GREEness metric were adopted as the method greenness assessment tools.
Topics: Humans; Ion-Selective Electrodes; Letrozole; Electrodes; Potentiometry; Graphite
PubMed: 37980444
DOI: 10.1038/s41598-023-47240-3 -
Inorganic Chemistry Nov 2023The most effective approach to mitigate the toxic effects of internal exposure of radiometals to humans is metal-ligand (ML) chelation therapy. Thorium (Th)-induced...
The most effective approach to mitigate the toxic effects of internal exposure of radiometals to humans is metal-ligand (ML) chelation therapy. Thorium (Th)-induced carcinogenesis as well as other health hazards to humans as a result of chronic internal exposure necessitates the development of efficient Th-decorporating agents. In this regard, chemical and biological studies were carried out to evaluate -(2-Acetamido)iminodiacetic acid (ADA), a comparatively cost-effective, readily available, and biologically safe complexing agent for Th decorporation. In the present work, detailed thermodynamic studies for complexation of ADA with Th(IV) have been carried out to understand Th-ADA interaction, using potentiometry, calorimetry, electrospray ionization mass spectrometry, and theoretical studies, followed by its biological assessment for Th decorporation. Thermodynamic studies revealed the formation of strong Th-ADA complexes, which are enthalpically as well as entropically favored. Interestingly, density functional theory calculations, to obtain a thermodynamically favored mode of coordination, showed the uncommon trend of lower denticity of ADA in ML than in ML, which has been explained on the basis of stabilization of ML by hydrogen bonding. The same was also reflected in the unusual trend of enthalpy for Th-ADA complexes. Biological experiments using human erythrocytes, whole human blood, and lung cells showed good cytocompatibility and ability of ADA to significantly prevent Th-induced hemolysis. Th removal of ADA from erythrocytes, human blood, and normal lung cells was found to be comparable with that of diethylenetriamine pentaacetate (DTPA), an FDA approved decorporating agent. The present study contributed significant data about Th complexation chemistry of ADA and its Th decorporation efficacy from human erythrocytes, blood, and lung cells.
Topics: Humans; Thorium; Erythrocytes; Calorimetry; Cell Death
PubMed: 37922372
DOI: 10.1021/acs.inorgchem.3c02296 -
Biological Trace Element Research Aug 2024High fluoride exposures can lead to adverse effects such as dental and bone fluorosis, as well as endocrine and cognitive developmental problems. Water is the main...
High fluoride exposures can lead to adverse effects such as dental and bone fluorosis, as well as endocrine and cognitive developmental problems. Water is the main dietary source of this ion, although significant concentrations have also been detected in other beverages widely consumed by the population such as soft drinks. A total of 200 soft drink samples (60 flavoured, 70 extracts, 60 fruit juice and 10 soft drinks) were analysed by fluoride ion selective potentiometry. A consumption of 330 mL was estimated for exposure assessment and subsequent F-risk assessment by soft drink consumption. The highest average concentration was found in extract soft drinks (2.45 ± 1.15 mg/L), followed by flavoured (1.71 ± 2.29 mg/L) and carbonated soft drinks (1.38 ± 0.40 mg/L), while the lowest was found in fruit juice soft drinks (1.09 ± 0.62 mg/L). The flavours with the highest concentration were tea-melon and tea-passion fruit with 3.66 ± 0.40 and 3.17 ± 0.56 mg/L respectively and the lowest was lemon flavour with 0.69 mg/L. The contribution of these beverages, considering the UL (Upper level) reference values set by EFSA (European Food Safety Authority) are between 3.28-41.78%, depending on age group and sex.
Topics: Fluorides; Humans; Carbonated Beverages; Dietary Exposure; Fruit and Vegetable Juices; Female
PubMed: 37922070
DOI: 10.1007/s12011-023-03937-0 -
Materials (Basel, Switzerland) Oct 2023Thin cross-linked films containing sulfonated poly(ether etherketone), SPEEK, and poly(vinyl alcohol), PVA, served as efficient photocatalysts for the reduction of CHCl...
Thin cross-linked films containing sulfonated poly(ether etherketone), SPEEK, and poly(vinyl alcohol), PVA, served as efficient photocatalysts for the reduction of CHCl when swollen in air-saturated solutions of formate buffers were photolyzed with 350 nm photons. The phototransformation generated CHCl, CO and Cl as products. The utilization of the continuous extraction method coupled with in situ potentiometry enabled kinetic determinations of the reaction progress. Quantum yields of halide ion formation, ϕ(Cl), larger than 1 were obtained in the presence of air. These findings, together with the occurrence of a post-irradiation Cl formation, indicated that the photoreduction took place via a chain process. Reductions photoinitiated by swollen films exhibited ϕ(Cl) values between 3 and 20 times higher than the reactions induced in solutions containing the two polymers. Also, the dependencies of ϕ(Cl) on CHCl or HCO concentration diverged significantly from the trends observed using solutions. Most findings are consistent with the occurrence of a reaction mechanism involving SPEEK radicals, •CO and •CHCl as chain carriers.
PubMed: 37895611
DOI: 10.3390/ma16206629 -
PloS One 2023Relying on freezer stored biospecimens is preferred in epidemiolocal studies exploring environmental pregnancy exposures and later offspring health. Storage duration may...
BACKGROUND
Relying on freezer stored biospecimens is preferred in epidemiolocal studies exploring environmental pregnancy exposures and later offspring health. Storage duration may increase the pre-analytical variability, potentially adding measurement uncertainty. We investigated evaporation of maternal serum after long-term biobank storage using ions (sodium, Na+; chloride, Cl-) recognized for stability and relatively narrow normal biological reference ranges in human serum.
METHODS
A chemical analysis study of 275 biobanked second trimester maternal serum from a large Danish pregnancy screening registry. Serum samples were collected between 1985-1995 and stored at -20°C. Ion concentrations were quantified with indirect potentiometry using a Roche Cobas 6000 analyzer and compared according to storage time and normal biological ranges in second trimester. Ion concentrations were also compared with normal biological variation assessed by baseline Na+ and Cl- serum concentrations from a separate cohort of 24,199 non-pregnant women measured before freezing with the same instrument.
RESULTS
The overall mean ion concentrations in biobanked serum were 147.5 mmol/L for Na+ and 109.7 for Cl-. No marked linear storage effects were observed according to storage time. Ion concentrations were consistently high across sampling years, especially for specific sampling years, and a relatively large proportion were outside respective normal ranges in second trimester: 38.9% for Na+ and 43.6% for Cl-. Some variation in concentrations was also evident in baseline serum used as quality controls.
CONCLUSIONS
Elevated ion concentrations suggest evaporation, but independent of storage duration in the present study (27-37 years). Any evaporation may have occurred prior to freezer storage or during the first 27 years. Other pre-analytical factors such as low serum volume have likely influenced the concentrations, particularly given the high within year variability. Overall, we consider the biobanked serum samples internally comparable to enable their use in epidemiological studies.
Topics: Pregnancy; Female; Humans; Biological Specimen Banks; Freezing; Sodium; Pregnancy Trimester, Second; Denmark
PubMed: 37883412
DOI: 10.1371/journal.pone.0293527 -
Scientific Reports Oct 2023The main limitation to the use of antimicrobial peptides (AMPs) as regular drugs, against antibiotic and antifungal resistance, mainly relates to their rapid degradation...
The main limitation to the use of antimicrobial peptides (AMPs) as regular drugs, against antibiotic and antifungal resistance, mainly relates to their rapid degradation by proteolytic enzymes. The introduction of suitable structural changes in the peptide chain can make the peptide less susceptible to the action of proteases, thus overcoming this problem. To improve the plasma stability of calcitermin, a metal-chelating AMP present in the human respiratory tract and investigated in the present study, C- and/or N- terminal modifications have been introduced in the native sequence. Evaluation of peptide stability has been performed to determine the half-life times in human plasma of both native calcitermin and its derivatives. However, the protection of the peptide termini can also affect its metal coordination behaviour. Thus, the characterization of Zn and Cu complexes has been performed by means of several techniques, including potentiometry, high-resolution mass spectrometry, UV-Vis, circular dichroism and EPR. On the basis of the obtained results, it was possible to compare the biological activity of the studied systems, taking into account both the metal-binding ability and the peptide stability to search for a link among them. A significant result of this study is that the N-terminal protection increases the calcitermin half-life over seven times and the formation of metal complexes confers resistance towards degradation almost doubling its half-life.
Topics: Humans; Anti-Bacterial Agents; Anti-Infective Agents; Chelating Agents; Circular Dichroism; Copper; Mass Spectrometry; Peptides
PubMed: 37880318
DOI: 10.1038/s41598-023-45437-0