Determination Of Quinine Research Articles

Підготовка проб сечі для вольтамперометричного визначення лікарських речовин та оцінювання методики з погляду еколологічності

This work discusses the primary methods of preparing urine samples for voltammetric analysis. To serve as model analytes, well-known and commonly used medicinal substances were employed. These substances exhibit distinct pharmacological effects and undergo varying transformations at the electrodes under voltammetry conditions. The selected model analytes encompass two alkaloids of plant origin – quinine and platyphylline, the platyphylline metabolite – its N-oxide, and the synthetic antibacterial drug sulfadimethoxine. The determination of model analytes in prepared samples of urine was carried out using a boron-doped diamond electrode and a dropping mercury electrode. The action of ultrasound on the urine sample turned out to be the optimal method of sample preparation, which allows you to liquid or other types of extraction and significant dilution of sample urine. Furthermore, the environmental aspects of voltammetric analysis for medicinal substance determination in urine, exemplified by quinine, were assessed. Various approaches, such as AGREEprep, AGREE metrics, Green Certificate, and Blue Applicability Grade Index (BAGI), were employed to evaluate environmental considerations. All these assessments yielded high ratings, indicating compliance with the principles of green analytical chemistry for the voltammetric technique in quinine determination in urine.

Fluorimetric determination of quinine using a portable system and digital image processing

Fluorimetric determination of quinine using a portable system and digital image processing

A Novel Equipment-Free Paper-Based Fluorometric Method for the Analytical Determination of Quinine in Soft Drink Samples.

A simple, equipment-free, direct fluorometric method, employing paper-based analytical devices (PADs) as sensors, for the selective determination of quinine (QN) is described herein. The suggested analytical method exploits the fluorescence emission of QN without any chemical reaction after the appropriate pH adjustment with nitric acid, at room temperature, on the surface of a paper device with the application of a UV lamp at 365 nm. The devices crafted had a low cost and were manufactured with chromatographic paper and wax barriers, and the analytical protocol followed was extremely easy for the analyst and required no laboratory instrumentation. According to the methodology, the user must place the sample on the detection area of the paper and read with a smartphone the fluorescence emitted by the QN molecules. Many chemical parameters were optimized, and a study of interfering ions present in soft drink samples was carried out. Additionally, the chemical stability of these paper devices was considered in various maintenance conditions with good results. The detection limit calculated as 3.3 S/N was 3.6 mg L-1, and the precision of the method was satisfactory, being from 3.1% (intra-day) to 8.8% (inter-day). Soft drink samples were successfully analyzed and compared with a fluorescence method.

Monitor Calibrator as an Alternative to Spectrofluorimeter: Determination of Quinine in Beverages and Medicinal Preparations

A possibility of using a monitor calibrator for the determination of luminescent compounds is shown on an example of quinine. The determination is based on the irradiation of a sample with broadband radiation in the visible and near UV spectral regions from a built-in source exciting phosphor molecules and the simultaneous registration of the radiation incident on the detector. Measurement conditions are selected. Quinine can be determined in the range of 60−750 µM, the limit of detection is 20 µM. The determination is not affected by common inorganic ions, as well as sweeteners and acidity regulators present in many beverages. The developed method of determination is applicable to the analysis of carbonated drinks and drugs. Compared to a traditional spectrofluorimeter, monitor calibrator is characterized by compactness, mobility, ability of detecting luminescence in cuvettes of various sizes and shapes, and lower cost.

Monitor Calibrator as an Alternative to Spectrofluorimeter: Determination of Quinine in Beverages and Medicinal Preparations

Monitor Calibrator as an Alternative to Spectrofluorimeter: Determination of Quinine in Beverages and Medicinal Preparations

Development of an image-based fluorometer with smartphone control for paper analytical devices.

This work describes the construction and evaluation of a fluorometer for use in paper analytical devices, using a smartphone to operate the instrument and to perform real-time image-based detection. In this approach, a circular PAD containing twenty analytical plates is rotated at 18° increments under a UV LED source, providing a sequential irradiation of plates and the detection of the luminescence with a lab-made application, capable of automatically identifying the analytical zones and collecting the RGB intensities from the selected pixels. As a proof of concept, the fluorometer performance was evaluated for the determination of quinine in beverages and riboflavin (B2 vitamin) in supplements. Quinine, which is less photoreactive, provided steady-state signals, while riboflavin, which rapidly degrades under UV photons, presented transient responses for RGB detection. For both analytes, linear calibration ranges (R2 > 0.99) were observed from 2.0 mg L-1 to 10.0 mg L-1 with limits of detection estimated at approximately 1.0 mg L-1. Nevertheless, it was demonstrated that successive additions of standard solutions to a single analytical plate of PAD could enhance the signal-to-noise ratios for less concentrated samples, acting as a pre-concentration step. In addition, suitable deviations for the signals (ca. 4.0%) and the absence of systematic errors for most samples (9 out of 11), when compared with a reference method at 95% confidence level, indicates that the proposed strategy is precise and accurate enough to be used as analytical tool for fluorescence detection in PAD.

Determination of quinine in tonic water at the miniaturized and polarized liquid–liquid interface

In this work we report an electrochemical approach to quantitative and qualitative analysis of quinine (QN) at the interface between two immiscible electrolyte solutions (ITIES). This was done at the macroscopic (macroITIES) and microscopic (µITIES) systems using ion transfer voltammetry (ITV). The linear response of the peak current vs. increasing concentrations of QN at the µITIES was from 2.50 µM to 29.13 µM and the corresponding calculated limit of detection (LOD) for the current signals originating from QN transfer from the aqueous to the organic phase was equal to 0.49 µM. Additionally, the influence of pH (2–12) of the aqueous phase on the recorded QN signals was investigated. We have found that our method is fully applicable for QN direct determination in non-treated tonic water, as confirmed on three different real samples from three different manufacturers. Finally, a number of validation parameters for the developed method are provided and discussed.

Design of an automatic spectrophotometric system

A Multi-Syringe Flow Injection Analysis (MSFIA) fluorometric system based on a 3D printing device hosting a CCD detector has been designed for the determination of quinine in soft drinks. A LED controlled by an electronic circuit was used as a radiation source. The entire system is connected to two USB outputs of a computer. The AutoAnalysis program has been used for data acquisition and treatment. The results are more accurate and precise than those obtained with a manual method using a conventional spectrofluorometer. This developed system is a viable alternative to reduce the consumption of reagents, the impact on the environment and reduce measurement costs.

A sensitive metal–organic framework nanosensor with cation-introduced chirality for enantioselective recognition and determination of quinine and quinidine in human urine

Additional chiral centers have been introduced into Cd-MOF to prepare a novel luminescent probe (1-C-Eu), which demonstrates promise in the enantioselective recognition and detection of quinine and quinidine in human urine.

Determination of quinine in drugs and beverages by fluorimetric method

Determination of quinine in drugs and beverages by fluorimetric method

Fabrication of an imprinted electrochemical sensor from l-tyrosine, 3-methyl-4-nitrophenol and gold nanoparticles for quinine determination

This study employed a molecularly imprinted composite (MIC) to develop a selective and very sensitive sensor for the determination of quinine. To fabricate the MIC sensor, 3-methyl-4-nitrophenol (MNP) and L-tyrosine (Tyr) were simultaneously electrodeposited in acidic media containing HAuCl4 to entrap Au nanoparticles (AuNPs) into the formed composite network. The effect of Tyr on the sensitivity and selectivity of the sensor and its electrochemical performance were evaluated. The signal reduction of the Fe2+probe during differential pulse voltammetry (DPV) was used to determine the concentration of quinine. The signal was found to be linear over the quinine concentration range of 0.1 to 1000 pM with a detection limit of 0.05 pM. The sensor was used to determine the quinine content of several plasma and urine samples.

Analytical aspects of smart (phone) fluorometric measurements

Facing the problem of a growing number of analyses, the need for using simple equipment appears. Smartphone-based optical detection is one of the most widely applied ideas nowadays. A personal device such as a smartphone equipped with a camera is affordable even in the source-limited places. After a simple modification, providing the light source of both defined properties and orientation, a smartphone may become an efficient analytical device. In this work we present a uniform methodology of such a modification, offering a complete hand-held device for fluorometric measurements. Inducing the fluorescence of the tested analytes was done by ordinary light-emitting diodes, and phone camera was used as a detector. Then the obtained images were analyzed using the RGB colour model to get proper calibration curves. The demonstration of the system performing with the use of fluorescein preceded the examples of determination of quinine, rhodamine B, riboflavin and calcein in real-life circumstances. Example determinations of the calcium ions in mineral water and riboflavin in alcoholic beverages are provided. The results obtained with the designed device are fully comparable to the ones obtained with the conventional fluorometric equipment. The presented systems allow determination of all the investigated analytes with satisfactory detection limits, in some cases down to ppb levels. Thanks to the use of LEDs, the system could be adapted for both measuring and inducing fluorescence in different analytes, characterized by various excitation wavelengths.

Determination of quinine in soft drinks using the fluorometry method

The fluorimetric method of analysis has been proposed for the qualitative and quantitative determination of the food flavoring additive quinine in the tonic water. The fluorimetric method of analysis has high sensitivity, selectivity and express speed compared to the other methods. The optimal conditions for the quinine fluorimetric determination in the soft drinks were found: solvent - 0.01 M sulfuric acid, excitation wavelength of 353 nm, luminescence wavelength of 452 nm, strobe parameters - signal delay of 0.85 μs, signal duration of 21.25 μs. To increase the sensitivity of the developed method, quinine luminescence was studied in the various concentrations of sulfuric acid from 0.005 to 1.000 M, and the quantum yield of quinine luminescence in all the investigated concentrations of sulfuric acid was calculated. It has been established that the highest quinine luminescence intensity, the highest quantum yield, and the lowest solvent background signal were observed in 0.01 M H 2 SO 4 . The influence of the related compounds of the food matrix on the fluorimetric determination of quinine was studied. It has been established that the content of such components as sugar and citric acid in the soft drinks does not affect the luminescent signal of quinine. The detection limit of quinine was calculated, which amounted to 0.0019 mg/dm 3 . In order to verify the correctness of the fluorimetric method, the results were compared with the spectrophotometric method (maximum absorption of quinine at 347 nm). The results obtained by the two methods were in good agreement, and the detection limit of the fluorimetric method was higher compared to the known works. The proposed technique could be used to control the quality and safety of the soft drinks. Keywords : quinine, fluorimetry, tonic water, luminescence quantum yield, strobe parameters. DOI: http://dx.doi.org/10.15826/analitika.2019.23.3.007 (Russian) A.А. Nikolaeva, A.A. Ivanov, E.I. Korotkova National Research Tomsk Polytechnic University, Lenina prosp., 30 Tomsk, 634050, Russian Federation

Challenges of HPLC determination of quinoline derivatives used in the treatment of malaria

ABSTRACTFully effective antimalarial drugs are yet to be isolated or synthesized, hence the search them continues. The study was aimed at establishing the most suitable conditions for the separation and determination of six biologically active alkaloids, quinoline derivatives, using high performance liquid chromatography with UV/Vis detection. The experiments involved the following derivatives: quinine, quinidine, cinchonine, cinchonidine, acetylcinchonine and acetylquinidine. Of the six stationary phases used, only the naphthylpropyl column enabled the separation of all alkaloids. The octadecyl column, considered by many analysts as a reference, did not provide successful separation. The naphthylpropyl column had also very good validation parameters, including a wide range of linearity, high values of correlation coefficients (0.9990‒0.9998) and low standard measurement uncertainty (1.8‒2.3 µg L‒1). The newly developed method was employed to evaluate the content of quinine in tonic-like beverages. The naphthylpropyl stationary phase provided ≤5% repeatability of quinine determination.

Rapid voltammetric method for quinine determination in soft drinks

A novel voltammetric assay for quinine (QN) determination using an electrochemically pretreated pencil graphite electrode is described. The detection limit of QN was 2 × 10−7 M. The method possesses some obvious advantages including extreme simplicity, rapid response, and low cost.

Compact detectors made of paired LEDs for photometric and fluorometric measurements on paper

The utility of strikingly simple and cheap optoelectronic detectors operating according to a Paired-Emitter-Detector-Diode (PEDD) principle for microfluidic paper-based analytical devices (μPAD) has been experimentally confirmed. The prototypes of these compact detectors have been made of only two customary light emitting diodes without any additional optical parts like lens, filters, fibers etc. Moreover, for their operation economic and portable equipment is required (low-power circuit and ordinary voltmeter). Photometric and fluorometric PEDDs for paper devices are developed. In both cases the possibility of their applicability in transmittance and reflectance modes of measurements are presented. In these investigations as model analytes some coloured and fluorescence substances have been handled, but the utility of several developed systems for real chemical analysis has also been demonstrated. The results of photometric determination of hemoglobin in human blood, as well as fluorometric determination of quinine in tonics and calcium ions in mineral waters using various PEDD-μPAD systems have been shown.

Quinine-Loaded Polymeric Nanoparticles: Validation of a simple HPLC-PDA Method to Determine Drug Entrapment and Evaluation of Its Photostability

Article history: Received on: 01/11/2015 Revised on: 26/11/2015 Accepted on: 22/12/2015 Available online: 27/02/2016 Liquid chromatographic method was developed and validated for quantitative determination of quinine in polymeric nanoparticles. The method was performed using a Waters RP-18 column using a mobile phase consisting of acetonitrile:water:triethylamine (60:40:0.01 v/v/v, and pH aqueous phase adjusted to 3.0 with phosphoric acid). The flow rate was 1.0 mL min -1 and the detection was achieved with a UV-PDA set at 232 nm. The response was linear over a range of 12.0 to 24.0 μg.mL -1 (r = 0.9995). The relative standard deviation values for intra-day and inter-day precision studies were less than 2% and the accuracy was 98.8% to Nc1 and 97.3% to Nc2. The samples free of quinine and quinine-loaded polymeric nanoparticles were subjected to photodegradation conditions. A considerable reduction of degradation of quinine occurred in polymeric nanoparticles. Through these results, it was clear that the nanoencapsulation of quinine protects the drug from degradation by exposure to UV-A light. The analytical method was validated according to International Conference on Harmonization Guidelines and Center for Drug Evaluation and Research.

Determination of Quinine, Quinidine, and Cinquinidine by Capillary Electrophoresis

This article presents the results of the research on a newly developed methodology for the separation and determination of quinine and its two derivatives. The analyzed compounds are biologically active, which are used in the treatment of malaria. The mixture of the analyzed compounds, i.e., hydrochlorides: quinidine, quinine, and cinquinidine, was dissolved in water and then exposed to optimization of separation and determination by isotachophoresis. The analysis was conducted with a varying number of steps and varying time of analysis, different intensities and voltages of the electric current, and different high voltage limits. For the ternary mixture, the optimal time of analysis was just over 8 min. On the other hand, the determination of cinquinidine had the shortest time of analysis (less than 3 min). The conducted validation of the developed methodology indicates very good conditions for the determination of quinidine, quinine, and cinquinidine.

Determination of Quinine and its Derivatives with High-Performance Liquid Chromatography

This article presents the results deriving from research made on the development of optimal conditions for chromatographic separation and determination of such compounds as: quinine, quinidine, and acetylquinidine. The compounds subject to analysis are used in the treatment of malaria. Three stationary phases were used in the examination: octadecyl, which is perceived by analysts as the standard one, and two aryl phases (benzylpropyl and naphthylpropyl). For the mobile phases, the following compounds were adopted: methanol, acetonitrile, and a mixture of acetonitrile/water/formic acid. The best separation of quinine, quinidine, and acetylquinidine was observed in the naphthylpropyl column with the application of methanol as the mobile phase. The coefficients of separation of these compounds with the flow of methanol of 0.8 mL min−1 were 1.17 and 1.14, respectively. However, no proper separation of the compounds was observed in the octadecyl column, regardless of the mobile form applied.

Substitution of Mercury Electrodes by Bismuth-Coated Screen-Printed Electrodes in the Determination of Quinine in Tonic Water

The bismuth-coated screen-printed electrode is shown to be a suitable and safe alternative to the classical mercury electrode in the voltammetric determination of quinine in tonic water. This experiment is appropriate for undergraduate analytical courses as it helps students understand the fundamentals of electroanalysis using preplated screen-printed electrodes and the importance of green electrochemistry. Student interest is piqued by using a familiar real-world sample, tonic water.