Selective Electrode Research Articles

A comparative study of green solid contact ion selective electrodes for the potentiometric determination of Letrozole in dosage form and human plasma

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 × 10–5–1.00 × 10–2, 1.00 × 10–6–1.00 × 10–2 and 1.00 × 10–8–1.00 × 10–3 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.

Evaluation of fluoride levels in areca nut, tobacco, and commercial smokeless tobacco products: a pilot study

Oral submucous fibrosis (OSMF) is a premalignant condition associated with chewing areca nut and tobacco products. We observed increased fluoride levels in some OSMF-endemic regions,and the observation suggested that fluoride exposure may contribute to its pathogenesis. This study aimed to assess the fluoride content of various smokeless tobacco items as a potential influencing source. Fluoride concentration was analysed in commercial areca nut products, including gutkha, pan masala, and raw areca nut, along with tobacco, slaked lime, and catechu samples from Karnataka, India. Fluoride was measured using alkali fusion and the ion selective electrode method. All products showed high fluoride, with catechu having the highest mean concentration at 51.20 mg/kg, followed by tobacco, gutkha, pan masala, processed areca nut, and raw areca nut. Fluoride was also elevated in soil, but not in water. The findings demonstrate substantial fluoride levels in popular types of smokeless tobacco, and highlight an overlooked source of exposure among consumers of gutkha, pan masala and similar oral tobacco-products. The fluoride content warrants an investigation of potential links with the occurrence and severity of OSMF.

Fluoridated orthodontic adhesives: Implications of release and recharge and their impact on shear bond strength in demineralized tooth surfaces.

This study measured fluoride release from a light-cured orthodontic adhesive resin (Vega type) at three time intervals (one day, one week, and one month), investigated the rechargeability of the resin, and assessed its impact on shear bond strength in demineralized tooth surfaces. This study used 30 recently extracted upper premolar teeth to explore the effects of fluoride release over specific time intervals. The teeth underwent demineralization and were categorized into groups based on time intervals: one day, one week, and one month. Subgroups within each interval underwent fluoride recharging through fluoride varnish application. Fluoride release and shear bond strength were assessed after etching with phosphoric acid gel, applying the orthodontic adhesive, and curing. The samples were stored in deionized water. Fluoride quantification used a selective electrode, while shear bond strength assessment employed a universal testing machine. Finally, statistical analysis of the data was performed using SPSS 22. The study found that after one month, the adhesive had the highest fluoride release and shear bond strength mean values. There were significant differences in fluoride release and shear bond strength between the various groups studied. The application of fluoride varnish around the orthodontic bracket resulted in a positive effect on the shear bond strength of the bracket.

A low-cost portable system for on-site detection of soil pH and potassium levels using 3D printed sensors

Accurate data on the nutrient content of soil is essential for optimum fertiliser application in agriculture. Frequent and regular soil tests hold the key to mitigate difficulties that arise from lack of accurate information for soil and crop management, such as increased costs for fertilisers, and environmental degradation. Traditionally soil nutrient contents levels are measured from laborious methods which involves collecting field samples and returning to the laboratory for analysis. Laboratory analysis often requires sample pre-treatment, chemical extractants and expensive instrumentation. A low-cost on-site detection method for soil nutrients can increase data necessary for smart fertiliser application that can in turn increase farm profit and ensure environmental protection. Here we present a low-cost miniaturised multi-ion sensing system for on-site detection of pH and potassium. The sensing system consists of a PSoC4 microcontroller and novel 3D printed miniaturised ion selective electrodes for the simultaneous determination of potassium and pH. The 3D printed electrode's pH sensing capability and potassium ion sensing was validated using known pH and potassium ion concentrations, exhibiting high selectivity and excellent Nernstian sensitivities for pH (−61.05 mV/pH) and potassium (49.50 mV/decade). Soil pore water samples from various locations and depths were extracted using a MacroRhizon sampler and tested using the novel portable detection system. On-site pH and potassium determinations were acquired in extremely small volumes samples without the requirement of sample preparation.

Differences in Parathyroid Hormone-Related Peptide and Serum Electrolytes in Acute Leukemia Patients

Acute leukemia is a clonal malignancy of myeloid or lymphoid precursor cells. Parathyroid hormone-related protein (PTHrp) is an 84 amino acid protein released by the parathyroid glands. Serum electrolyte disturbances are common in acute leukemia patients. This study aimed to determine the difference in the levels of PTHrp and serum electrolytes (sodium, potassium, calcium ion) in acute leukemia patients. An observational analytic research, cross-sectional approach was performed at the Dr. Moewardi Hospital in Surakarta between June and August 2019 with 43 subjects. Acute leukemia, based on the FAB classification, is divided into two groups (myeloid and lymphoid lineage). The serum was used for measurement of PTHrp levels with enzyme immunoassay (ELISA) principle (the Rayto RT-2100C) and serum electrolyte with the Ion Selective Electrode (ISE) method (AVL analyzer). The data were tested by comparison test and ROC curve, p was significant if <0.05, and the confidence interval was 95%. Acute leukemia subjects comprised 24 lymphoid lineages (55.8%) and 19 (44.2%) myeloid lineages subjects. The mean age was 25 (7-47) years, with 18 (41.9%) male subjects and 25 (58.1%) female subjects. The mean sodium level was 136 (132-140) mmol/L, with a mean level of 134.38±4.75 mmol/L and 137.00 (121-143) mmol/L in the lymphoid and myeloid lineage groups, respectively. The cut-off point for serum sodium levels was 135.5 mmol/L, with an AUC of 0.679, a sensitivity of 73.7%, and a specificity of 67.7%. There was a significant difference in serum sodium electrolyte levels in acute leukemia patients (p=0.046) but not in acute leukemia patients' serum potassium, calcium ion, and PTHrp levels (p=0.415; p=0.912 and p=0.293, respectively). Further research was needed in the chronic leukemia population and other research variables related to electrolyte balance.

Fabrication of an efficient hierarchical mesoporous 2D-MoS2/CNT/polypyrrole based composite electrodes for competitive and selective U6+ removal using capacitive deionization: Mechanistic evaluation through cyclic voltammetry

In this work, efficient and selective carbonaceous electrode materials based on hierarchical mesoporous functionalized carbon nanotubes, 2D-MoS2 nanosheets electrodeposited with variable content of polypyrrole (PPy) were prepared. The simple etching reaction between HNO3 and carbon nanotubes did not only modify the surface but also improved its hydrophilicity. The annealing of carbon nanotubes and electrodeposition of PPy increased the mesopore volume to total volume ratio (Vmeso/Vt) from 0.42 to 0.86. The composite materials were characterized wisely using different characterization techniques and employed for efficient U6+ electro-assisted sorption through capacitive deionization. Electrode material with PPy content (0.3 M) exhibited good specific capacitance Csp (100.2 F/g), improved Vmeso (0.61 cm3/g), superb Vmeso/Vt ratio (0.86) and large specific surface area SBET (149.7 m2/g). The stated electrode showed fast sorption kinetics (teq=30 min), admirable selectivity and exhibited the experimental sorption capacity of 274.50 mg/g at − 0.90 V. Electrochemical impendence spectroscopic study revealed that the resulting material exhibited relatively small charge transfer resistance (1.19 Ωcm2), minute electrolytic resistance (0.91 Ωcm2) and large double layer constant phase element (0.0368 S sn/ cm2). These significant characteristics promoted U6+ ions diffusion inside the hierarchical porous electrode surface for better performance of electrosorption process. This new class of hierarchical mesoporous composite electrodes may be used as potential supercapacitor materials not only for removal of uranium but also for other potent desalination applications.

A Mission Simulating the Search for Life on Mars with Automated Drilling, Sample Handling, and Life Detection Instruments Performed in the Hyperarid Core of the Atacama Desert, Chile.

We report on a field demonstration of a rover-based drilling mission to search for biomolecular evidence of life in the arid core of the Atacama Desert, Chile. The KREX2 rover carried the Honeybee Robotics 1 m depth The Regolith and Ice Drill for Exploration of New Terrains (TRIDENT) drill and a robotic arm with scoop that delivered subsurface fines to three flight prototype instruments: (1) The Signs of Life Detector (SOLID), a protein and biomolecule analyzer based on fluorescence sandwich microarray immunoassay; (2) the Planetary In Situ Capillary Electrophoresis System (PISCES), an amino acid analyzer based on subcritical water extraction coupled to microchip electrophoresis analysis; and (3) a Wet Chemistry Laboratory cell to measure soluble ions using ion selective electrodes and chronopotentiometry. A California-based science team selected and directed drilling and sampling of three sites separated by hundreds of meters that included a light-toned basin area showing evidence of aqueous activity surrounded by a rocky desert pavement. Biosignatures were detected in basin samples collected at depths ranging from 20 to 80 cm but were not detected in the surrounding area. Subsurface stratigraphy of the units drilled was interpreted from drill sensor data as fine-scale layers of sand/clay sediments interspersed with layers of harder material in the basins and a uniform subsurface composed of course-to-fine sand in the surroundings. The mission timeline and number of commands sent to accomplish each activity were tracked. The deepest sample collected (80 cm) required 55 commands, including drilling and delivery to three instruments. Elapsed time required for drilling and sample handling was less than 3 hours to collect sample from 72 cm depth, including time devoted to recovery from a jammed drill. The experiment demonstrated drilling, sample transfer technologies, and instruments that accomplished successful detection of biomolecular evidence of life in one of the most biologically sparse environments on Earth.

Nitrogen-doped carbon aerogel framework with in situ encapsulated ZrO2 nanoparticles as pseudocapacitive anode for phosphorus uptake

Phosphorus reduction is crucial for controlling eutrophication and protecting the aquatic environment. Nonetheless, traditional methods suffer from secondary pollution and high costs. Capacitive deionization (CDI) is a novel electrochemical approach for phosphorus removal, which is low-cost and environmentally friendly. Its performance is highly correlated with the electrode material. Herein, a novel nitrogen-doped carbon aerogel framework encapsulated with ZrO2 nanoparticles (ZrNC) was rationally fabricated and employed as an anode for phosphorus removal. The experimental results revealed that the N site and ZrO2 could enhance the physicochemical properties, electrochemical activity, and additional pseudocapacitive contribution, thus raising the phosphorus removal capacity. The optimal ZrNC-3 electrode demonstrated superior phosphorus capture (18.26 mg P/g), low energy consumption at 1.2 V (0.0256 kWh/m3 and 4.159 kWh/kg), outstanding phosphorus selectivity, and excellent stability. Mechanism investigation suggested phosphorus can form mono- or bi-dentate inner-sphere complexes (Zr–O–P) by ligand exchange with ZrO2 sites under an electric field and combined with unsaturated Zr sites and N species by electrostatic attraction. This study presents a promising conception for designing and applying metal oxide/carbon complexes in selective phosphorus uptake electrodes.

Fate of fluorine in stratified samples from BGL gasifier at Hailar Chemical Plant, Inner Mongolia: An intermediate process perspective

This study investigated the fate of Fluorine (F) during the super high temperature (2000 °C) gasification process by analyzing 23 stratified samples inside the British Gas Lurgi (BGL) gasifier in production. Through sequential chemical extraction (SCEP), ion selective electrode (ISE), scanning electron microscope with energy dispersive spectrometer (SEM-EDS), high-resolution transmission electron microscope with energy dispersive spectrometer (HRTEM-EDS) and X-ray diffraction (XRD), this article complements the intermediate forms of transformation of F, in addition to the methods of deduction of the fate of F through input and output.Overall, the concentration of fluorine gradually decreases with increasing temperature and ≈1200 °C (14th layer) is the key temperature for its volatilisation. This may be related not only to the volatility of organic matter, but also to the significant contribution from the melting of a large amount of silicate and aluminosilicate minerals in the sample.In addition, the fluorine concentration remained stable from layer 14 to layer 27 (≈2000 °C), rather than continuing to evaporate, due to the formation of a new, stable mode of fluorine occurrence: Ca-P-F-Si minerals have been identified. The free and active SiO2, possibly derived from the melting of quartz and kaolinite, played a key role in preventing the melting of fluorapatite. The mechanism of formation of the new refractory materials (Ca-P-F-Si minerals) needs to be further validated by laboratory and computer simulations.

Determination of Some Organic and Inorganic Nutritional Constituents in Beta Vulgaris Roots Prepared in Different Methods

The nutritional value of the roots of Iraqi Beta vulgaris plant that have been prepared using several conventional techniques will be evaluated in the current research. One of the best and most important nutritional sources of iron, nitrate of nitrogen, magnesium, potassium, ascorbic acid, and folic acid is the juice of beta vulgaris roots.
 Spectrophotometric techniques like UV-Visible, HPLC, and AAS have been used to estimate the levels of some organic and inorganic nutritional constituents and determine the level of the nitrate ion using an ion selective electrode technique in the prepared beta vulgaris root juice. The concentration of these organic and inorganic components varies depending on how the Beta vulgaris juice is prepared. The roots of Beta vulgaris have been processed in four different ways.
 Ascorbic acid content is greatest in the prepared sample with sodium chloride (4.124 mg in 200 mL), while the sample treated with acetic acid has a high concentration of Betalains (10.96 mg in 200 mL) and folic acid (5.736 mg in 200 mL).
 The potassium (552 mg in 200 mL) and magnesium (54 mg in 200 mL) concentrations in juice from the acetic acid-treated sample were relatively higher than those obtained from other methods, whereas the prepared sample with NaCl has a high concentration of NO3- (616 mg in 200 mL) and the prepared sample with cool water has a high concentration of iron (0.75 mg in 200 mL).

Application of superhydrophobic Ti3C2 Mxene-based screen-printed ion-selective electrode for determination of Ca2+ concentration

Ti3C2 Mxene is a remarkable electrochemical material owing to its high conductivity, large specific surface area, and high electrical capacity. It can be applied in all-solid-state ion-selective electrodes to improve the ion-electron conversion efficiency and reduce the resistance. However, Ti3C2 Mxene is hydrophilic, which will form a water layer between the ion-selective membrane and the substrate, resulting in response potential drift. In this study, Ti3C2 Mxene functionalized with octadecyltrichlorosilane was developed as the ion-electron conversion layer (solid contact layer), and a polymer membrane containing N, N, N', N' -Tetracyclohexyl-3-oxapentanediamide was used as the Ca2+ selective membrane on a screen-printed electrode substrate. An all-solid Ca2+-selective electrode (SPE/SH-Ti3C2/Ca-ISM) was prepared. The results from cyclic voltammetry and electrochemical impedance spectroscopy proved the high capacitance and fast charge transfer ability of the Ti3C2 Mxene modified electrode. In addition, it shows good performance in the water layer test and anti-interference test and improves the response speed and stability of potential. The linear response range of this disposable screen-printed electrode to Ca2+ is 10−6∼10−1 M, the detection limit is 10−6.2 M, and the response time is about 15 s. The electrode can accurately and quickly determine the level of Ca2+ in serum samples of dairy cows.

Fluoride Levels in Borehole Water: The Case of Chiradzulu District in Malawi

Aims: The objective of this study was to determine the levels of fluoride in borehole water samples.
 Study Design: The total of eight samples were collected from five villages in Chiradzulu and transported in cooler ice-bath to the laboratory for the analysis.
 Place and Duration of Study: The study was conducted in the Department of Chemistry and Chemical Engineering Laboratories, at University of Malawi in the month of June.
 Methodology: The ion selective electrode technique was used to assess fluoride levels. Physicochemical water parameters were measured with multi-meters. 
 Results: The results obtained ranged from 2.26 to 3.08 mg/L, 136 to 561 mg/L, 261-1212 μs/cm and 6.27 to 6.97, for Fluorides, TDS, conductivity and pH, respectively. Levels of fluorides exceeded permissible limits for borehole water established by WHO and were below the standards for MBS
 Conclusion: The results attained in the scope of the study support coloration of teeth observed amongst individuals in study communities, helping to understand that groundwater is not suitable for consumption. Therefore, the study provides recommendation for urgent implementation of defluoridation measures to provide clean and safe water for the existing community members.

Development of a Concentration Cell Potentiometric Method for Fe2+ and Fe3+ Speciation

The speciation of Fe2+ and Fe3+ iron ions using the concentration cell potentiometric method has been developed. The determination and speciation of metals that have been used include potentiometry using comparison electrodes, selective ion electrodes, and voltammetry. The concentration cell potentiometric method has the advantages of simple equipment, the use of common metal electrodes, high selectivity, and relatively low detection limits. The method validation results for Fe2+ and Fe3+ ion speciation was LOD: Fe2+ 0.22 mg/L and Fe3+ 0.29, LOQ: Fe2+ 0.92 mg/L and Fe3+ 0.01 mg/L; precision (1.17%; 1.2%) and accuracy (95.57%; 93.15%) based on CV Horwtz. This method has been well applied for Fe2+ and Fe3+ speciation in natural water samples. The concentrations of Fe2+ and Fe3+ species in Sekanak river water were (1.88 mg/L; 2.07 mg/L). Concentration of Fe2+ and Fe3+ species in well water samples (0.5 mg/L; 1.32 mg/L).

POTENTIOMETRY IN DETERMINING THE CONDITIONS FOR THE FORMATION OF TETRAFLUORBORATE AS AN ANALYTICAL FORM OF BORON

The present paper deals with the research on the optimal conditions for the formation of fluoroborate as an analytical form of boron. Despite numerous scientific publications related to the determination of boron using various methods involving [BF4]ˉ ions as an analytical form, the conditions for obtaining the latter differ significantly. This difference is likely due to the complexity of the H3BO3-F--H3O+ system, where polymolecular forms of hydrofluoric acid can exist. Factors such as the inability to measure pH using a glass electrode, the velocity of the complexation process, and the requirement for specialized labware and equipment resistant to aggressive environments contribute to this complexity. In this study, potentiometry with PVC plasticized [BF4]ˉ - sensors, known for their metrological and operational characteristics, was used as a convenient tool to investigate such systems. The [BF4]ˉ - selective electrode based on the electroactive substance ion pair 2-(N-ethylcarbazole-3)-ethenyl-1,3,3-trimethyl-3H-indole tetrafluoroborate, which retains its metrological characteristics in acidic and strongly acidic environments and exhibits selectivity up to F-(= -4. 0), was employed as a sensor.
 The sensor allowed for the study of [BF4]ˉ - complex formation under different reaction conditions by recording kinetic curves in EMF-time coordinates. The yield of the analytical form was estimated at different concentrations of acid, fluoride ions, and temperature. The obtained data were used to construct the yield surface of tetrafluoroborate, revealing that the optimal conditions for the formation and stability of tetrafluoroborate at room temperature are a medium of 1 M sulfuric acid and 0. 25 M NH4F. Under these conditions, the yield of [BF4]ˉ reaches 99% within 10 minutes. Although the use of phosphoric acid does not allow for the attainment of an appropriate yield of the analytical form under equilibrium conditions, its low process velocity makes it suitable for kinetic - potentiometric determination of boron. This characteristic was utilized to develop a method for the determination of boron in phosphoric acid using the fixed-time method.
 Keywords: tetrafluoroborate ion; potentiometric sensor; kinetic determination of boron.

B-026 Evaluation of Colorimetric and Electrolyte Test Assays on the Fuji Dri-Chem NX700I Clinical Chemistry Analyzer

Abstract Background The FUJI DRI-CHEM NX700i holds 28 colorimetric and 3 electrolyte test assays and analyzes up to 190 tests/hour (colorimetry + electrolytes). A STAT testing position is available. The colorimetric method slide is a multilayered slide composed of dry chemical ingredients needed for the reaction quantifying enzymes and substrates by colorimetric methods. The potentiometric method slide contains ion selective film electrodes. Calibration is done with QC cards except for CRP working with a calibrator. Each test needs 10μL of sample except for CRP (5 μL) and ISE (50μL for all 3 tests). Methods In this study the Fuji Dri-Chem NX700i was evaluated using serum samples. The parameters investigated were albumin (ALB), blood urea nitrogen (BUN), creatinine (CRE), total bilirubin (TBIL), aspartate aminotransferase (AST/GOT), Alanine Aminotransferase (ALT/GPT), γ-glutamyltransferase (GGT), C-reactive protein (CRP), lipase (LIP), triglycerides (TG) and ammonia (NH3). Interferences from hemolytic, lipemic, icteric or highly elevated total protein samples were excluded according to the manufacturers method specific declarations and studied separately. Method comparison was done by measuring 50 samples for each analyte at the same time on the NX700i and the Siemens Atellica CH analyzer. For each parameter inter- (controls, n = 10) and intra-assay (patient samples, n = 10) coefficients of variation (CV) were calculated for low, medium and high concentrations. Results Inter-assay CVs (n = 10) were 1.1 to 7.7% (Low), 0.7 to 3.9% (Medium) and 0.8 to 5.5% (High). Intra-assay CVs (n = 10) were <0.01 to 9.5% (Low), <0.01 to 3.7% (Medium) and 0.7 to 3.3% (High). Method comparison (Passing-Bablok Regression) of routine samples from hospital patients revealed good agreement of the two methods with correlation coefficients of r = 0.98 and higher except for LIP (0.83), NH3 (0.87) and Alb (0.93). Conclusion The FUJI DRI-CHEM NX700i shows good intra- and inter-assay precision with low CVs and excellent correlation with the Siemens Atellica CH analyzer.

B-024 An Evaluation of the Analytical Performance of the New Beckman Coulter DxC 500 AU Clinical Chemistry System

Abstract Background The Beckman Coulter DxC 500 AU clinical chemistry analyzer* is the latest system from Beckman Coulter. It is a fully automated, random-access analyzer, designed for low to medium throughput laboratories, with a throughput of 800 tests/hour including ion selective electrodes. The purpose of this study was to evaluate the analytical performance of the new DxC 500 AU and to compare the performance against the current AU480 and DxC 700 AU analyzers. Methods To assess the performance of the DxC 500 AU, Beckman Coulter assays were selected for evaluation that covered a range of sample types and assay methodologies. Precision was assessed using pooled human samples over 20 days following CLSI guideline EP05-A3. The linear range was assessed following CLSI EP06-A. The DxC 500 AU was compared to the AU480 and DxC 700 AU analyzers using a minimum of 100 samples spanning the dynamic range based on CLSI guideline EP09c-ED3. Results IgG Serum: OSR6x172 Estimates of repeatability and within laboratory precision were assessed following EP05-A3 at multiple critical analyte concentrations. The IgG serum assay exhibits total imprecision of < 6 % with a within run imprecision of ≤ 3.5 %. The IgG serum assay demonstrated acceptable linearity throughout the analytical measuring range of 75 to 3000 mg/dL following CLSI EP06-A. A method comparison study following CLSI EP09c-ED3 compared the IgG serum assay on the DxC 500 AU against the AU480 and DxC 700 AU. Serum patient samples (n > 100) measured across the analytical range were analyzed using Weighted Deming regression and yielded a slope of 1.046, an intercept of −20.2884 mg/dL and correlation coefficient R = 0.9979 against the DxC 700 AU and yielded a slope of 1.005, an intercept of −3.6578 mg/dL and correlation coefficient R = 0.9973 against the AU480. CRP Serum (Highly Sensitive): OSR6x99 Estimates of repeatability and within laboratory precision were assessed following EP05-A3 at multiple critical analyte concentrations. The CRP serum assay exhibits total imprecision of ≤10 %CV or ≤0.02 SD with a within run imprecision of ≤5 %CV or ≤0.02 SD. The CRP serum assay demonstrated acceptable linearity throughout the analytical measuring range of 0.2 to 80 mg/L following CLSI EP06-A. A method comparison study following CLSI EP09c-ED3 compared the CRP serum assay on the DxC 500 AU against the AU480 and DxC 700 AU. Serum patient samples (n > 100) measured across the analytical range were analyzed using Weighted Deming regression and yielded a slope of 0.990, an intercept of 0.0421 mg/dL and correlation coefficient R = 0.9997 against the DxC 700 AU and yielded a slope of 0.995, an intercept of −0.0008 mg/dL and correlation coefficient R = 0.9998 against the AU480. Conclusion The results of the study demonstrated excellent analytical performance of the new Beckman Coulter DxC 500 AU analyzer and confirms comparable performance to the AU480 and DxC 700 AU analyzers. *Product In development. Pending clearance by the United States Food and Drug Administration and achievement of CE compliance. Not currently available for in vitro diagnostic use.

Vancomycin selective electrode based on molecularly imprinted polymer

Vancomycin selective electrode based on molecularly imprinted polymer

Sensing the impact of diet composition on protein fermentation by direct electrochemical NH4+ sensing in gastrointestinal digesta

The correlation between nutritional habits and gut health directly impacts the gut-brain axis via a complex and not yet fully disclosed communication network. Establishing a link between our food intake and specific physiological responses as well as a better knowledge of diseases and the gut microbiota involves solving a challenging puzzle of biochemical pathways. Our understanding is limited by the inaccessibility of the gastrointestinal region to routine non-invasive chemical analysis. Here, we move a step further toward the direct assessment of a protein fermentation product, i.e., ammonium ions, via Ion Selective Electrodes (ISEs) in gastrointestinal digesta samples. By modulating the digestible protein content of the diet regimes of two groups of pigs, we discriminate the level of protein fermentation with a straightforward quasi-invivo detection method which does not require any sample preparation. Our results show more than a 2-fold increase in ammonium ion concentration (from 180 ppm to 400 ppm) in the proximal colon for a diet based on poorly digestible proteins compared with a diet based on easily digestible proteins. Our approach shows good correlation with a standard laboratory technique for the determination of NH4+, i.e., the Indophenol Blue Method. Our results show the direct sensing of a protein fermentation product in a real matrix and demonstrate the great potential of potentiometric sensors to assess ammonium concentration profiles along the gastrointestinal tract for diets varying in protein digestibility and fermentation.

Fluoride content of common legume beans consumed in Ethiopia

ABSTRACT. The most widely used legume beans food in Ethiopia are fava beans (Vicia faba), green gram (Vigna radiata), white lupin (Lupinus albus), and three types of kidney beans (Phaseolus vulgaris). These legume crops are grown in various regions of Ethiopia and can absorb significant amounts of fluoride from air, water, and soil. This study examined the fluoride content of legume beans collected from four different regions of Ethiopia by ion selective electrode potentiometry. Fluoride concentrations in this study were found to range from 1.9 to 22.8 mg/kg. Fava bean sample from Asella was found to contain higher fluoride (22.8 mg/kg) than in the fava beans from other sites and other beans from any site. Fluoride levels (13.0 mg/kg) in kidney bean from Migira was in the middle of the range while the fluoride levels (2.5 mg/kg) in the white lupin and green gram (1.9 mg/kg) were found in the lower end of the range. This study indicates that daily consumption of 100 g of fava and kidney beans may results in health problem while that of green gram and white lupin are safe for human health (will not exceed 3 mg/day set by Food and Nutrition Board of USA).
 KEY WORDS: Fava bean, Green gram, Kidney beans, White lupin, Food, Fluoride
 Bull. Chem. Soc. Ethiop. 2023, 37(6), 1325-1336. DOI: https://dx.doi.org/10.4314/bcse.v37i6.3

Determination of forced convection effects on the response of membrane-based ion-selective electrodes via numerical solution to the Navier-Stokes-Nernst-Plank-Poisson equations

Ion selective electrodes (ISEs) enable measurements via the build-up of a phase boundary potential at the surface of a sensing membrane. While a framework exists to understand the performance of ISEs in stagnant samples, the influences of fluid flow on ISEs are less studied. We model the transport of ions in solution occurring near interfaces between ISE membranes and aqueous samples when subject to an external flow. We developed a numerical model extending the Pressure-Implicit with Splitting of Operators (PISO) algorithm to incorporate the Navier-Stokes-Nernst-Plank-Poisson system of equations. We find that external flow distorts the aqueous side of the formed double layer at the ISE membrane and aqueous sample interface, leading to an increase in the phase boundary potential. The change in potential is shown to be a function of a novel set of dimensionless numbers, most notably the Debye Length Reynolds number, i.e., the Reynolds number with the Debye Length as the system dimension.