Ion-association Complex Research Articles

Validated Spectrofluorometric Assay for Folic Acid Determination in Pure and Pharmaceutical Forms via Basic Fuchsin Fluorescence Quenching.

A simple, specific, sensitive, rapid, and cost-effective spectrofluorometric method for quantifying folic acid has been developed using basic fuchsin as a fluorescence quenching agent. This method relies on the quenching effect of folic acid on the inherent fluorescence of basic fuchsin, facilitated by their interaction in Britton-Robinson buffer solution at pH 9, leading to the formation of an ion-associated complex. The decrease in fluorescence intensity of basic fuchsin was measured at 730 nm, with excitation at 365 nm. The method demonstrated a linear relationship (R2 = 0.9977) between the quenching fluorescence intensity (ΔF) and folic acid concentration over the range of 4-20 μg/mL, with a detection limit of 0.17 μg/mL. The method showed no significant interference from common excipients found in pharmaceutical tablets. The results obtained were in good agreement with those from high-performance liquid chromatography, with no significant differences in precision or accuracy. This spectrofluorimetric method was successfully applied to determine the folic acid content in various commercial pharmaceutical tablets.

Streamlined turn-off fluorescence sensing of Donepezil: Enhancing evaluation in pharmaceutical formulations, quality control labs, and biological fluids at nano levels

Donepezil (DPZ) is used to treat Alzheimer’s disease by increasing acetylcholine in the brain, necessitating precise analytical methods for its evaluation. This study aims to develop and validate a new turn-off fluorescence sensing method for quantifying DPZ, enhancing its evaluation in pharmaceutical formulations, quality control laboratories, and biological fluids. By leveraging the fluorescence-quenching interplay between DPZ and tetrabromofluorescein, the assay parameters were fine-tuned to enhance the development of an ion-associated complex. The developed method demonstrated a measurement range from 40 to 800 ng/mL, with detection and quantification limits of 12.6 ng/mL and 38 ng/mL, respectively. However, the successful application of the method to commercial DPZ tablets and plasma samples confirmed its effectiveness for both quality control labs and clinical research settings. It ensured accurate content uniformity and high precision, making it ideal for routine DPZ monitoring. In contrast to previous methods, this approach emphasizes environmental sustainability, evaluated using advanced tools like the Eco score scale, AGREE, RGB12, and BAGI. These tools facilitated a thorough assessment of the method’s ecological impact and sustainability, underscoring its advantage over traditional methods in terms of environmental responsibility.

Paper based analytical devices for ions determination in nasal secretions demonstrating association with olfactory function

Nasal ions environment plays a crucial role in maintaining nasal physiology and supports olfactory transmission. Addressing the limited research on nasal ion levels and their association with olfactory function, paper-based sensors were developed for determination of sodium, potassium, calcium and chloride in the nasal mucus of healthy volunteers and patients with olfactory dysfunction. Multi-walled carbon nanotubes and carbon quantum dots from beetroot were incorporated into paper substrate where sensors were designed with ion association complexes for sodium, potassium, calcium and chloride enhancing the recognition sensing capabilities. The sensors composition was optimized, including ion-exchange materials and plasticizers, to enhance sensitivity and selectivity. The performance of the sensors is evaluated based on Nernstian slope, dynamic range, detection limit and response time. Selectivity of the sensors was tested and the results demonstrated high selectivity for the target ions. The sensors were successfully determined sodium, potassium, calcium and chloride levels in nasal mucus of healthy volunteers and patients with olfactory dysfunction. The results revealed elevated calcium levels in patients with olfactory dysfunction, highlighting associated diagnostic implications. This suggests that the proposed sensors could serve as a diagnostic tool for olfactory evaluation, particularly in resource-constrained settings where access to advanced diagnostic tools is limited.

Estimation of Imatinib Mesylate by Extractive Colorimetric Methods in Bulk and Pharmaceutical Dosage Form

Simple sensitive and accurate extractive spectrophotometric methods have developed for the estimation of Imatinib mesylate in pharmaceutical dosage form. The methods are based on the formation of coloured complexes by the drug with reagents like bromophenol blue, solochrome dark blue and bromocresol green in acidic medium. The ion associated complexes were formed and quantitatively extracted under the experimental condition in chloroform. The absorbance values were measured at 420 nm, 495 nm and 430 nm respectively. The proposed methods were validated statistically. Recoveries of methods were carried out by standard addition methods. The linearity was found to be 1-8 μg/ml, 2 -16μg/ml, 1-16 μg/ ml for methods 1, 2 and 3 respectively. The low values of standard deviation and percentage RSD indicate high precision of methods. Hence these methods are useful for routine estimation of Imatinib mesylate in tablets.

Selective separation of lead (II) from foodstuffs and environmental samples by adsorption onto modified truffle peels with nanoparticles [TPs/TiO2(NP)] as a novel biomass

ABSTRACT This study aims to examined truffle peel powder modified with nanoparticles [TPs/TiO2(NP)] as a solid adsorbent for the removal of lead ions Pb(II) from environmental media and foodstuffs. The characterisation of TPs/TiO2(NP) was studied by a Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and energy dispersive X-ray (EDX). Through the application of several adsorption isotherm models, the Langmuir at 25°C revealed to be most appropriate, having the highest R2 (0.961), and the maximum Pb(II) adsorption capacity was found 0.908 mg g−1. In addition, the various kinetics models were applied, and the data was well-fitted by the pseudo-second order kinetics model (R2 = 0.9997). Thermodynamic parameters indicated that the technique of adsorption had been endothermic (∆H = 30.79 J mol−1), The value of ΔG indicates the spontaneous and physical nature (- 29.26 KJ mol−1) and the positive value of ∆S indicates a moderate step of sorption of the Pb(II) complex ion associate (98.32 J). Foodstuffs (energy drinks and ice pops) and environmental samples (tap water) were successfully confirmed with a good recovery.

Determination of Methdilazine by Extractive Colorimetric Method from Pharmaceutical Dosage Form

Simple sensitive and accurate ion pair complex formation, extractive spectrophotometric methods have developed for the estimation of methdilazine hydrochloride in pharmaceutical dosage form. The methods are based on the formation of ion paired coloured complexes by the drug with reactive dyes like Congo red, picric acid and methyl orange in acidic medium. The ion associated complexes were formed and quantitatively extracted under the experimental condition in chloroform. The absorbance values were measured at 490 nm, 400 nm, and 430 nm respectively. The proposed methods were validated statistically. Recoveries of methods were carried out by standard addition method. The linearity was found to be 1-10 μg/ml, 2-12 μg/ml, and 1-14 μg/ml for methods respectively. The low values of standard deviation and percentage RSD indicate high precision of methods. Hence these methods are useful for routine estimation of methdilazine hydrochloride in pharmaceutical dosages.

Spectrofluorometric determination of calcium in the human nasal secretions investigating the association with olfactory function

Ionic microenvironment of the nasal secretions especially calcium ions play essential role in the olfactory transmission. However, there is a critical need to determine the free calcium levels in healthy people's nasal secretions in contrast to those of patients with olfactory impairment. A selective spectrofluorometric method was created to quantify nasal calcium levels utilizing its quenching ability to the fluorescence of the functionalized carbon quantum dots. The surface of carbon quantum dots was functionalized with calcium ionophore A23187 and ion association complex, calcium phosphotungstate, to improve the selectively to quantify calcium ions. The functionalized carbon quantum dots exhibited a concentration-dependent fluorescence quenching upon interaction with calcium ions. Different factors influencing the quenching process were done to provide efficient analytical process. The new method, demonstrated accurate calcium determination over the concentration range of 200–4000 ng/mL. The suggested technique was used to measure the calcium in the nasal secretions of both healthy people and patients with olfactory impairment. The findings revealed significantly higher calcium levels in the patient with olfactory dysfunction (healthy vs. patient; 735 ± 20 ng/mL vs. 2987 ± 37 ng/mL, p < 0.05).

Enhancing the Sustainability of Eco-Friendly Potentiometric Ion-Selective Electrodes for Stability-Indicating Measurement of Ethamsylate: Application in Bulk and Pharmaceutical Formulations.

Through the use of sustainable and green chemistry concepts, scientists need to decrease waste, conserve energy, and develop safe substitutes for hazardous compounds, all for protecting and benefiting society and the environment. Four novel eco-friendly ion selective electrodes (ISE) were generated to determine Ethamsylate (ETM) in bulk powder and different pharmaceutical formulations. The present electrodes were fabricated to clearly distinguish ETM from a variety of inorganic, organic ions, sugars, some common drug excipients and the degradation product, hydroquinone (HQ) of ETM, and thus used for stability-indicating methods. The electrodes fabrication was based on 2-nitrophenyl octyl ether (NPOE) that was employed as a plasticizer in electrodes 1, 2, and 3 within a polymeric matrix of polyvinyl chloride (PVC) except for electrode 4, in which dibutyl sebacate was used as a plasticizer. Electrodes 1 and 2 were fabricated usingtetradodecylammonium bromide as an anionic exchanger, adding 4-sulfocalix-8-arene as an ionophore only to electrode 2 and preparing electrode 1 without incorporation of an ionophore. The fabrication of electrodes 3 and 4 was based on ethamsylate-tetraphenylborate (ETM-TPB) as an ion-association complex in a PVC matrix. The environmental sustainability was assessed using the green analytical procedure index (GAPI), and analytical greenness metric for sample preparation (AGREEprep). Electrodes 1 and 2 had linear dynamic ranges of 10-1-10-5 mol/L and 10-1-10-4 mol/L, respectively, with a Nernstian slope of 49.6 and 53.2 mV/decade, respectively. Electrodes 3 and 4 had linear dynamic ranges of 10-1-10-4 mol/L, with a Nernstian slope of 43.9 and 40.2 mV/decade, respectively. The electrodes' selectivity coefficients showed good selectivity for ETM. The utility of 4-sulfocalix-8-arene as an ionophore had a significant influence on increasing the membrane sensitivity and selectivity of electrode 2 compared to other electrodes. Four novel eco-friendly ISEs were used for determination of ETM in bulk powder and different pharmaceutical formulations. Different experimental parameters were performed to optimize the determination conditions such as solvent mediators, dynamic response time, effect of pH, and temperature. Stability-indicating measurement of ETM in the presence of its degradate HQ and co-formulated drug tranexamic acid. Using new ecological assessment tools to determine whiteness and greenness profiles.

A non-extraction sequential injection method for determination of loratadine using formation of its ion-association complex with bromocresol purple in acetonitrile

The formation of an ion-association complex (IA) between sulfonephthalein dye and basic nitrogen-containing compound in an organic solvent medium has been for the first time used to develop an automated SIA method. In highly polar aprotic solvents, the tautomeric equilibrium for such dyes is strongly shifted towards the colorless lactonic form. The addition of a basic nitrogen-containing substance leads to the formation of IA with a highly colored quinonoid form, which is accompanied by an increase in the absorbance of the dye band at approximately 400 nm. Protonation of pyridine nitrogen in loratadine, structure and binding places of IA were shown using quantum-chemical calculations. The very simple, direct and non-extraction spectrophotometric SIA method with high throughput of 43 h−1 was developed based on the formation of IA between loratadine and bromocresol purple in the medium of acetonitrile used both as solvent and carrier. The calibration graph was linear in the concentration range from 1.0 to 20 mg L−1 with correlation coefficient of 0.9992. The developed method was successfully applied to the analysis of pharmaceutical formulations.

Determination of phosphate in food based on molybdenum yellow derivatization coupled with resonance Rayleigh scattering method.

This paper proposed a rapid, selective and sensitive molybdenum yellow derivatization coupled with Resonance Rayleigh scattering (MYD-RRS) method for detection of phosphate. Under the acidic condition, phosphate can be selectively transformed to Keggin type of phosphomolybdic acid (PMA, i.e., PMo12O403-) through molybdenum yellow derivatization reaction prior to RRS detection. The PMA can further react with cationic methyl violet (MV) to form larger PMA-MV ion association complexes, generating significant RRS signal. The concentration of phosphate was linearly related to the RRS signal in the range of 8-200ng/mL, with the determining coefficient (R2) of 0.9973 and the detection limit of 4ng/mL. The analytical procedure can be completed within 10min and the RRS signal intensity can remain stable more than 4h. The method showed good stability toward temperature and time, and good anti-interference capability. The method was applied to the determination of phosphate in real food samples with the recovery of 85-117% and RSD of 1-5.2%. With the advantages of rapidness, high sensitivity and good selectivity, the MYD-RRS method exhibits great potential to the determination of phosphate in food. It also provides an instructive strategy for detection of analytes with weak RRS signal.

Liquid–liquid extraction of strontium from acidic solutions into ionic liquids using crown ethers

90Sr is one of the most monitored fission products. New efficient methods for strontium separation are therefore sought. Over the past 20 years, crown ethers solutions in ionic liquids (ILs) have been confirmed to efficiently extract strontium from acidic solutions. Despite all the work done in this field, the extraction mechanism is still not completely clear. Depending on experimental conditions, the extraction is believed to proceed either in the form of an ion-association complex [Sr·CE·(NO3)2] or via exchange between [Sr·CE]2+ and two IL cations. This work aims to study the influence of several extraction parameters and compare them with the presumed mechanisms.

Validation of Molnupiravir by Application of Reactive Dyes from Pharmaceutical Dosages

Simple sensitive and accurate ion pair complex formation with reactive dyes, extractive spectrophotometric methods have developed for the estimation of molnupiravir in pharmaceutical dosage form. The methods are based on the formation of ion paired coloured complexes by the drug with reactive dyes like Congo red, eriochrome black T and methyl orange in acidic medium. The ion associated complexes were formed and quantitatively extracted under the experimental condition in chloroform. The absorbance values were measured at 490nm, 500nm, and 430nm respectively. The proposed methods were validated statistically. Recoveries of methods were carried out by standard addition method. The linearity was found to be 4.0-24.0μg/ml, 2-12μg/ml, and 2-16μg/ml for methods respectively. The low values of standard deviation and percentage RSD indicate high precision of methods. Hence these methods are useful for routine estimation of molnupiravir in pharmaceutical dosages.

Extractive Spectrophotometric Determination of Meropenem in Pharmaceutical Formulations

A simple, sensitive extractive spectrophotometric method for the determination of Meropenem has been proposed. The method is based on the formation of an ion-association complex between the drug and acidic dye methyl orange, which was a pale yellow colored chromogen extracted with dichloro methane from the aqueous phase, measured at 400 nm. The Beer’s law was obeyed in the concentration range of 10 - 30 µg/ml. Thus results of the proposed method was validated statistically and applied successfully to the determination of Meropenem in bulk and its dosage forms.

Analisis Kadar Vitamin B1 dalam Kacang Panjang (Vigna sinensis L.) Menggunakan Spektrofotometri Ultraviolet-Visible

A Research of vitamin B1 in long beans (Vigna sinensis L.) analyzed using ultraviolet-visible (uv-vis) spectrophotometry has been carried out at a wavelength of 435.6 nm. Vitamin B1 reacted with bromthymol blue to form a yellow ion-associated complex in an ammonia-ammonium chloride as a buffer solution pH 7.6 which could be observed with a polyvinyl alcohol solubilizing agent. Long beans were boiled in water for 5, 10 and 15 minutes at 100oC. Vitamin B1 in long beans (Vigna sinensis L.) without boiling 0.0981 % ± 0.00021, boiling 5, 10 and 15 minutes were 0.0935 % ± 0.00015; 0.0834 % ± 0.00010 and 0.0743 % ± 0.00010 and the vitamin B1 in the long bean boiled water at 5, 10 and 15 minutes boiling were 0.00102 % ± 0.000004; 0.00110 % and 0.00117 % ± 0.00001. It’s can be concluded that boiling long beans (Vigna sinensis L.) can cause a decrease in vitamin B1 which decreases with increasing boiling time and vitamin B1 in the cooking water increase due to the nature of vitamin B1 which is easily soluble in water

Consecutive spectrophotometric determination of phosphate and silicate in a sequential injection lab-at-valve flow system

A new highly sensitive and selective sequential injection lab-at-valve spectrophotometric method for the consecutive determination of silicate and phosphate is described. The proposed method is based on the formation of specific ion-association complexes (IAs) of 12-heteropolymolybdates of phosphorus and silicon (12-MSC) with Astra Phloxine. The addition of an external reaction chamber (RC) to the SIA manifold made it possible to significantly improve the conditions for the formation of the analytical form used. The formation of the IA took place in the RC; the solution is mixed by passing an air flow through it. The interfering effect on the determination of phosphate from silicate was completely eliminated by choosing an acidity at which the rate of 12-MSC formation is very low. The use of secondary acidification in the determination of silicate led to the complete exclusion of the influence of phosphate. The tolerable ratio of phosphate to silicate and vice versa is about 100-times, which allows the analysis of most real samples without the use of masking agents or complex separation steps. The determination ranges are 3.0–60 μg L−1 for phosphate as P(V) and 2.8–56 μg L−1 for silicate as Si(IV) at a throughput of 5 samples h−1. The detection limits are 5.0 and 3.8 μg L−1 for phosphate and silicate, respectively. Silicate and phosphate were determined in the tap water, river water, mineral water, main water of the Krivoy Rog (Ukraine) region, and the certified reference material of carbon steel.

Extraction and Determination of Sildenafil Citrate by Spectrophotometry: Classical Versus Factorial Design Optimization

In this work, the complexation and extraction processes of sildenafil citrate (SC) were evaluated by using classical optimization versus factorial design methodology. The selected factors were based on the reaction of sildenafil with methyl orange (MO) as a chromogenic reagent via the formation of ion-association complex in acidic buffer media, followed by extraction with chloroform and quantitatively measured by visible spectrophotometry at λmax of 427 nm. The optimization step was first carried out by classical one-factor-at-a-time (OFAT) from which the extracted results were exploited in the experimental design optimization by using 24-1 fractional factorial and 32 full factorial designs for the chosen variables such as pH, concentration of reagent, reaction time, extraction time and temperature. Results obtained from fractional factorial design 24-1 showed that only the variables pH, MO concentration and their interaction based on analysis of variance (ANOVA) in term of Pareto chart, were statistically significant at 95% confidence level. Under the optimized conditions, the assay method of SC was validated in term of the analytical figures of merit. SC can be determined in concentration range of 0.5-40 µg mL-1 with correlation coefficient of 0.9991, detection limit (S/N) of 0.15 µg mL-1, RSD (n=10) of 1.43%, accuracy as %Erel of -2.23% and mean percent recovery of 97.77±0.87. The proposed method was applied for the determination of SC in commercial medicaments without fear from excipients interferences with the assay procedure.

Simple Extractive Spectrophotometric Method for Determination of Molnupiravir from Pharmaceutical Formulation

Simple sensitive and accurate spectrophotometric methods have developed for the estimation of molnupiravir in pharmaceutical dosage form. The methods are based on the formation of coloured complexes by the drug with reagents like bromophenol blue, solochrome dark blue and bromocresol green in acidic medium. The ion associated complexes were formed and quantitatively extracted under the experimental condition in chloroform. The absorbance values were measured at 420nm, 495nm and 430nm respectively. The proposed methods were validated statistically. Recoveries of methods were carried out by standard addition methods. The linearity was found to be 1.0-12.0μg/ml, 2 -14μg/ml, 1-10μg/ml for methods 1, 2 and 3 respectively. The low values of standard deviation and percentage RSD indicate high precision of methods. Hence these methods are useful for routine estimation of molnupiravir in tablets.

Investigation of eco-friendly fluorescence quenching probes for assessment of acemetacin using silver nanoparticles and acriflavine reagent

The non-steroidal anti-inflammatory medication acemetacin was assessed via two straightforward green spectrofluorimetric techniques. The quenching-dependent derivatizing spectrofluorimetric reactions are the master point of this study. Acriflavine-based method (Method I) depends on forming an ion association complex between acriflavine and the drug in a ratio of 1:1, decreasing the former's fluorescence intensity. Acriflavine or Ag NP's intensity-related quenching action goes linearly with the acemetacin concentration in the 2.0–20.0 µg/mL and 1.0–16.0 µg/mL ranges, respectively. The second quenching mechanism depends on using the silver nanoparticles (Ag NP's) as a fluorescence probe (Method II); Ag NP's were prepared from reducing silver nitrate using sodium borohydride. Both methods could be applied to determine pure and pharmaceutical dosage forms of acemetacin. The methods proved valid according to the international conference on harmonization (ICH) guidelines. In addition to this, this work has been estimated under green criteria assessment tools. There is no significant difference between the proposed and the comparison methods after the statistical interpretation.

Vanadium-Containing Anionic Chelate for Spectrophotometric Determination of Hydroxyzine Hydrochloride in Pharmaceuticals

Four azo dyes known to form anionic complexes with V(V) were investigated as potential liquid-liquid extraction-spectrophotometric reagents for the antihistamine medication hydroxyzine hydrochloride (HZH). A stable ion-association complex suitable for analytical purposes was obtained with 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR). The molar absorption coefficient, limit of detection, linear working range, and relative standard deviation in the analysis of real pharmaceutical samples (tablets and syrup) were 3.50 × 104 L mol-1 cm-1, 0.13 μg mL-1, 0.43-12.2 μg mL-1, and ≤2.7%, respectively. After elucidating the molar ratio in the extracted ion-association complex (HZH:V = 1:1), the ground-state equilibrium geometries of the two constituent ions-HZH+ and [VO2(HTAR)]--were optimized at the B3LYP level of theory using 6-311++G** basis functions. The cation and anion were then paired in four different ways to find the most likely structure of the extracted species. In the lowest-energy structure, the VO2 group interacts predominantly with the heterochain of the cation. A hydrogen bond is present (V-O···H-O; 1.714 Å) involving the terminal oxygen of this chain.

Sertraline: Theoretical Studies and a New Potentiometric PVC Membrane Sensor for its Determination

Background: Sertraline (ST) hydrochloride is an anti-depressant of the selective serotonin reuptake inhibitor (SSRI) class. Potentiometric sensors are an appealing route for detecting drugs due to some advantages in terms of sensitivity, feasibility, selectivity, fast response, tolerance to turbidity and colour of solutions, and cost-effectiveness. Methods: A mixture of polyvinyl chloride powder (PVC) with o-nitrophenyl octyl ether and the ion association complex was dissolved in tetrahydrofuran (THF) to prepare the membrane for the proposed sensor. The sensor was calibrated and then electrochemically used for detecting ST in pharmaceutical samples. Results: The near Nernstian response was observed for a concentration of 1.0 x 10-8 – 1.0 x 10-2 mol L-1 with 58.62 mV as a slope per concentration decade. This direct potentiometric measurement resulted in average recoveries of 96.0 ± 0.2%. Moreover, good selectivity for sertraline with respect to many inorganic and organic cations was observed. Conclusion: The proposed sensor was simple to use and produced accurate and precise results. The molecule's chemical and biological activities were revealed using theoretical calculations. Regarding the chemical activities, calculations were made on the 3-21g and 6-31g while the SDD bases were set at B3LYP, HF, and the M062X level. Molecular docking calculations were designed against cancer proteins in order to have details regarding the molecule's biological activity.