Determination of Cinnarizine in Pure and Pharmaceutical Formulations

Two simple, rapid and sensitive extractive spectrophotometric methods have been developed for the assay of cinnarizine (CNR) in pure and pharmaceutical formulations. The methods are based on the formation of chloroform soluble ion‐association complexes of CNR with thymol blue (TB) and with cresol red (CR) inNaOAc‐AcOH buffer of pH 3.6 for TB and in KCl‐HCl buffer of pH 1.6 for CR with absorption maxima at 405 nm and at 403 nm for TB and CR, respectively. Reaction conditions were optimized to obtain the maximum color intensity. The systems obeyed Beer's law in the range of 0.6–15.8 and 0.8–16.6 μg mL^?1 for TB and CR, respectively. Various analytical parameters have been evaluated and the results have been validated by statistical data.     

Determination of Labetalol Hydrochloride in Drug Formulations by Spectrophotometry

A validated, selective and sensitive spectrophotometric method has been developed for the determination of labetalol hydrochloride in commercial dosage forms. The method is based on the coupling reaction of positive diazonium ion of 4‐aminobenzenesulfonic acid with phenolate ion of labetalol to form a colored azo compound which absorbs maximally at 395 nm. Under the optimized experimental conditions, the color is stable up to 2 h and Beer's law is obeyed in the concentration range of 0.8–17.6 μg mL^?1 with a linear regression equation of A = 4.84 × 10^?4 + 7.864 × 10^?2 C and coefficient of correlation, r = 0.9999. The molar absorptivity and Sandell's sensitivity are found to be 2.874 × 10⁴ L mol^?1 cm^?1 and 0.013 μg cm^?2 per 0.001‐absorbance unit, respectively. The limits of detection and quantitation of the proposed method are 0.08 and 0.23 μg mL^?1, respectively. The intra‐day and inter‐day precision variation and accuracy of the proposed method is acceptable with low values of standard analytical error. The recovery results obtained by the proposed method in drug formulations are acceptable with mean percent recovery ± RSD of 99.97 ± 0.52 ‐ 100.03 ± 0.63%. The results of the proposed method compared with those of Bilal's spectrophotometric method indicated excellent agreement with acceptable true bias of all samples within ± 2.0%.     

Three Spectrophotometric Methods for the Determination of Oxomemazine Hydrochloride in Bulk and in Pharmaceutical Formulations Using Bromocresol Green,Congo Red,and Methyl Orange

Abstract

Three simple, sensitive, and highly accurate spectrophotometric methods have been developed for the determination of oxomemazine hydrochloride (OXO‐HCl) in bulk and in pharmaceutical formulations. These methods are based on the formation of yellow ion‐pair complexes between the examined drug and bromocresol green (BCG), congo red (CR), and methyl orange (MO) as reagents in universal buffer solution of pH 3.0, 5.5, and 3.5, respectively. The formed complexes were extracted with chloroform and measured at 413, 495, and 484 nm, respectively for the three systems. The best conditions of the reaction were studied and optimized. Beer's law was obeyed in the concentration ranges 2.0–18.0, 2.0–14.0, and 2.0–16.0 µg ml^?1 with molar absorptivity of 4.1×10⁴, 1.1×10⁴, and 3.5×10⁴ mol^?1cm^?1, for the BCG, CR, and MO methods, respectively. Sandell's sensitivity, correlation coefficient, detection, and quantification limits are also calculated. The proposed methods have been applied successfully for the analysis of the drug in pure and in its dosage forms. No interference was observed from common pharmaceutical excipients and additives. Statistical comparison of the results with those obtained by HPLC method shows excellent agreement and indicates no significant difference in accuracy and precision.     

Spectrophotometric Determination of Dextromethorphan Hydrobromide and Ketamine Hydrochloride in Pure and Dosage Forms

Three simple, sensitive and accurate spectrophotometric methods have been developed for the determination of dextromethorphan hydrobromide (DEX) and ketamine hydrochloride (KET) in dosage forms. These methods are based on the formation of ion‐pair complexes with bromocresol green (BCG), bromocresol purple (BCP), and bromophenol blue (BPB) in acidic medium. The coloured ion‐pair products are measured at 419, 409 and 417 nm for DEX and at 417, 408 and 416 nm for KET using BCG, BCP and BPB, respectively. Beer's law was obeyed in the range of 2.0–22 μg mL^?1 for DEX and 2.0–16 μg mL^?1 for KET. The composition of the ion‐pair was established by continuous variation and molar ratio methods. The proposed methods were applied successfully for the determination of DEX and KET in dosage forms applying the standard addition technique and compared statistically with the official methods. The molar absorptivity, Sandell sensitivity, detection and quantification limits were also calculated.     

Spectrophotometric Determination of Ondansetron Hydrochloride in Pharmaceutical Bulk and Dosage Forms

A rapid, simple and accurate spectrophotometric method is developed for the determination of ondansetron hydrochloride in pure and tablet formulations. The method depends on the charge‐transfer complexation between ondansetron base as n‐electron donor with chloranil as π‐acceptor to give a colored complex, which absorbs maximally at 470 nm. Beer's law is obeyed in the concentration ranges 70–980 μg mL^?1 with molar absorptivity of 4.47 × 10² L mole^?1 cm^?1. The proposed method is precise, accurate and specific for the quantitative determination of drug in bulk and tablet formulations.     

First Electroanalytical Methodology for the Determination of Hordenine in Dietary Supplements using a Boron‐doped Diamond Electrode

The present work describes the first electrochemical investigation and a simple, rapid and modification‐free electroanalytical methodology for quantification of hordenine (a potent phenylethylamine alkaloid) using a boron‐doped diamond electrode. At optimized square‐wave voltammetric parameters, the observed oxidation peak current in 0.1 M HClO₄ at +1.33 V (vs. Ag/AgCl) increased linearly from 5.0 to 100 μg mL^?1 (3.0×10^?5–6.1×10^?4 M), with detection limit of 1.3 μg mL^?1 (7.8×10^?6 M). The applicability of the developed method was tested with the determination of hordenine in the commercial dietary supplement formulations.     

Fourth Order Derivative Spectrophotometric Determination of Benzyl Alcohol in Piroxicam Injections

Piroxicam is a drug with analgesic and anti‐inflammatory properties. It is present in numerous pharmaceutical preparations. Injectable forms usually contain benzyl alcohol as an excipient, which is used as a blocking anesthetic (4%) and an antiseptic (4–10%). In this work, spectrophotometric methodology was used in order to determine benzyl alcohol in piroxicam injectable formulations by applying the fourth derivative method adopting the zero‐crossing technique. The results obtained show that the method has significant advantages over other reported methods and is appropriate for routine pharmaceutical analysis. The method showed excellent linearity in the range of 2–100 μg mL^?1 with limit of detection (S/N = 3) 0.07 μg mL^?1 (6.47 × 10^?7 M). The proposed method could be applied successfully for the determination of benzyl alcohol in injectable formulations with average % recovery of 100 ± 0.61.     

Novel Biomedical Sensors for Flow Injection Potentiometric Determination of Creatinine in Human Serum

Coated‐wire (CW) and tubular (Tu) type membrane sensors for creatinine are developed. These consist of creatinine tungstophosphate(CTP), creatinine molybdophosphate (CMP) and creatinine picrolonate (CPC) ion‐pair complexes as electroactive materials dispersed in plasticized poly(vinyl chloride) matrix membranes. Electrochemical evaluation of these sensors under static (batch) mode of operation reveals near‐Nernstian response with slopes of 62.9, 58.1, and 55.2 mV decade^?1 over the concentration range 1×10^?2–5.0×10^?6, 1×10^?2–7.5×10^?5, and 1×10^?2?3.1×10^?5 mol L^?1. The lower detection limits are 0.39, 3.49, and 2.20 μg mL^?1 creatinine with CTP, CMP and CPC membrane based sensors plasticized with o‐NPOE, respectively. Tubular and coated wire CTP membrane sensors are incorporated in flow‐through cells and used as detectors for flow injection analysis (FIA) of creatinine. The intrinsic characteristics of the detectors under hydrodynamic mode of operation in a low dispersion manifold are determined and compared with data obtained under static mode of operation. With 10^?2 mol L^?1 phosphate buffer of pH 4.5 as a carrier solution, the tubular and coated wire CTP detectors exhibit rapid response of 58.9 and 50.7 mV decade^?1 over the concentration range 1×10^?2–1×10^?5 mol L^?1 and detection limits of 0.39 μg mL^?1 and 0.85 μg mL^?1, respectively. Validation of the assay methods with the proposed sensors by measuring the lower detection limit, range, accuracy, precision, repeatability and between‐day‐variability reveals good performance characteristics confirming applicability for continuous determination of creatinine. The sensors are used for determining creatinine in human blood serum at an input rate of 40 samples per hour. No interferences are caused by creatine, most common anions, cations and organic species normally present in biological fluids. The results favorably compare with data obtained using the standard spectrophotometric method.     

Spectrophotometric Determination of Esomeprazole Magnesium in Commercial Tablets Using 5‐Sulfosalicylic Acid and N‐Bromosuccinimide

Two simple, sensitive and economical spectrophotometric methods have been developed for the determination of esomeprazole magnesium in commercial dosage forms. Method A is based on the reaction of esomeprazole magnesium with 5‐sulfosalicylic acid in methanol to form a yellow product, which absorbs maximally at 365 nm. Method B utilizes the reaction of esomeprazole magnesium with N‐bromosuccinimide in acetone‐chloroform medium to form α‐bromo derivative of the drug peaking at 380 nm. Under the optimized experimental conditions, Beer's law is obeyed in the concentration ranges of 2‐48 and 10‐100 μg mL^?1 with molar absorptivity of 2.11 × 10⁴ and 4.57 × 10⁴L mol^?1 cm^?1 for methods A and B, respectively. The limits of detection for methods A and B are 0.35 and 0.46 μg mL^?1, respectively. No interference was observed from excipients commonly present in tablet formulations. Methods A and B are successfully applied to the commercial tablets for the estimation of esomeprazole magnesium with good accuracy and precision. The results compare favorably with the reference spectrophotometric method indicating no significant difference between the methods compared.     

Development and validation of a generic RP‐HPLC PDA method for the simultaneous separation and quantification of active ingredients in cold and cough medicines

A novel generic reverse phase high performance liquid chromatography (RP‐HPLC) method is developed and validated for simultaneous determination of seven pharmaceutically active ingredients, namely, acetaminophen, dextromethorphan, doxylamine, phenylephrine, guaifenesin, caffeine and aspirin. All seven ingredients were quantified in soft gel, syrup and tablet formulations of the over‐the‐counter US‐marketed products, as per the guidelines of the International Conference on Harmonization. The separation was achieved in a 16 min run time on an Agilent Zorbax Phenyl column using a gradient method with two mobile phases. Mobile phase A was 0.15% trifluoro acetic acid in purified water and while mobile phase B was a mixture of acetonitrile and methanol (750:250 v/v) with 0.02% trifluoro acetic acid. The flow rate was 1.0 mL min^?1 and injection volume was 10 μL. Detection was performed at 280 nm using a photodiode array detector. As part of the method validation, specificity, linearity, precision and recovery parameters were verified. The concentration and area relationships were linear (R² > 0.999), over the concentration ranges 20–120 μg mL^?1 for acetaminophen, 75–450 μg mL^?1 for dextromethorphan, 31.25–187.5 μg mL^?1 for doxylamine, 25–150 μg mL^?1 for phenylephrine, 25–150 μg mL^?1 for aspirin, 6.5–39 μg mL^?1 for caffeine and 12–72 μg mL^?1 for guaifenesin. The relative standard deviations for precision and intermediate precision were <1.5%. The proposed RP‐HPLC generic method is applicable for routine analysis of cold and cough over‐the‐counter products.     

Study on the Interaction between a Novel Ionic Liquid Probe and Anionic Surfactants Using Resonance Light Scattering Spectra and Its Analytical Application

The interaction between anionic surfactants (AS) and 1‐hexadecyl‐3‐methylimidazolium bromide [C₁₆mim]Br was studied by using resonance light scattering (RLS) technique, UV‐Vis spectrophotometry and fluorometric methods. In Britton Robinson (BR) buffer (pH 6.0), [C₁₆mim]Br reacted with AS to form supermolecular complex which resulted in enhancement in RLS intensity. Their maximum RLS wavelengths were all at 390 nm. Some important interacting experimental variables, such as the solution acidity, [C₁₆mim]Br concentration, salt effect and addition order of the reagents, were investigated and optimized. Under the optimum conditions, quantitative determination ranges were 0.001–7 μg·mL^?1 for dodecyl sodium sulfate (SDS), 0.001–6 μg·mL^?1 for sodium dodecylbenzene sulfonate (SDBS) and 0.005–7 μg·mL^?1 for sodium lauryl sulfonate (SLS), respectively, while the detection limits were 1.3 ng·mL^?1 for SDS, 1.0 ng·mL^?1 for SDBS and 5.1 ng·mL^?1 for SLS, respectively. Based on the ion‐association reaction, a highly sensitive, simple and rapid method has been established for the determination of AS.     

Simultaneous determination of caffeine,paracetamol, and ibuprofen in pharmaceutical formulations by high‐performance liquid chromatography with UV detection and by capillary electrophoresis with conductivity detection

Paracetamol, caffeine and ibuprofen are found in over‐the‐counter pharmaceutical formulations. In this work, we propose two new methods for simultaneous determination of paracetamol, caffeine and ibuprofen in pharmaceutical formulations. One method is based on high‐performance liquid chromatography with diode‐array detection and the other on capillary electrophoresis with capacitively coupled contactless conductivity detection. The separation by high‐performance liquid chromatography with diode‐array detection was achieved on a C₁₈ column (250×4.6 mm², 5 μm) with a gradient mobile phase comprising 20–100% acetonitrile in 40 mmol L^?1 phosphate buffer pH 7.0. The separation by capillary electrophoresis with capacitively coupled contactless conductivity detection was achieved on a fused‐silica capillary (40 cm length, 50 μm i.d.) using 10 mmol L^?1 3,4‐dimethoxycinnamate and 10 mmol L^?1 β‐alanine with pH adjustment to 10.4 with lithium hydroxide as background electrolyte. The determination of all three pharmaceuticals was carried out in 9.6 min by liquid chromatography and in 2.2 min by capillary electrophoresis. Detection limits for caffeine, paracetamol and ibuprofen were 4.4, 0.7, and 3.4 μmol L^?1 by liquid chromatography and 39, 32, and 49 μmol L^?1 by capillary electrophoresis, respectively. Recovery values for spiked samples were between 92–107% for both proposed methods.     

A Simple Approach to Simultaneous Electroanalytical Quantification of Acetaminophen and Tramadol Using a Boron‐doped Diamond Electrode in the Existence of Sodium Dodecyl Sulfate

The present work describes the individual, selective and simultaneous quantification of acetaminophen (ACP) and tramadol hydrochloride (TRA) using a modification‐free boron‐doped diamond (BDD) electrode. Cyclic voltammetric measurements revealed that the profile of the binary mixtures of ACP and TRA were manifested by two irreversible oxidation peaks at about +1.04 V (for ACP) and +1.61 V (for TRA) in Britton‐Robinson (BR) buffer pH 3.0. TRA oxidation peak was significantly improved in the presence of anionic surfactant, sodium dodecyl sulfate (SDS), while ACP signal did not change. By employing square‐wave stripping mode in BR buffer pH 3.0 containing 8×10^?4 mol L^?1 SDS after 30 s accumulation under open‐circuit voltage, the BDD electrode could be used for quantification of ACP and TRA simultaneously in the ranges 1.0–70 μg mL^?1 (6.6×10^?6–4.6×10^?4 mol L^?1) and 1.0–70 μg mL^?1 (3.3×10^?6–2.3×10^?4 mol L^?1), with detection limits of 0.11 μg mL^?1 (7.3×10^?7 mol L^?1) and 0.13 μg mL^?1 (4.3×10^?7 mol L^?1), respectively. The practical applicability of the proposed approach was tested for the individual and simultaneous quantification of ACP and/or TRA in the pharmaceutical dosage forms.     

Simple and Sensitive Extractive Spectrophotometeric Method for the Assay of Mebeverine Hydrochloride in Pure and Pharmaceutical Formulations

Simple, sensitive, rapid and cost effective extraction spectrophotometric methods are described for the assay of mebeverine hydrochloride (MBH) in bulk samples and pharmaceutical formulations. These two methods (Bromophenol blue and Erichrome Black‐T) are based on the formation of chloroform soluble ion‐pair complexes of MBH with Bromophenol blue (BPB) and with Erichrome Black‐T (EBT), to form yellow and pink colored chromogen in a Glycine‐HCl buffer of pH 2.4 (BPB) and in a KCl‐HCl buffer of pH 1.4 (EBT) with absorbance maximum at 416 nm and at 524 nm for BPB and EBT respectively. The calibration graph is found to linear over 0.2–20 μg/mL (BPB) and 0.2–20 μg/mL (EBT), with molar absorptivity values of 1.8295 × 10⁴ 1 moL^?1 cm^?1 and 1.5896 × 10⁴ 1 moL^?1 cm^?1, respectively. The LOD (Limit of Detection) were found to be 0.090 μg/mL and 0.084 μg/mL and LOQ (Limit of Quantification) were 0.2997 μg/mL and 0.2730 μg/mL for the BPB and EBT method, respectively. The results of analysis for the two methods have been validated statistically and by recovery studies. The results are compared with those obtained with reported method. The proposed methods are simple, sensitive, accurate and suitable for quality control applications.     

Quantitative Analysis of Nicorandil in Commercial Tablets by Spectrophotometry

The main aim of this work is to develop and validate a spectrophotometric method for the determination of nicorandil in commercial tablets. The method is based on the reduction of the nitroxy ethyl group of nicorandil into carbonyl compound and nitrite ion by NH₄Cl and Zn dust. The nitrite ion thus formed reacts with potassium iodide and starch in dilute HCl medium to form a blue product, which absorbs maximally at 550 nm. Beer's law is obeyed in the concentration range 0.4‐4.0 μg mL^?1 with molar absorptivity of 7.92 × 10⁴L mol^?1 cm^?1. The detection limit is 0.017 μg mL^?1. The reaction conditions are optimized and validated as per the International Conference on Harmonisation guidelines (USA). The proposed method has been applied successfully for the determination of nicorandil in commercial tablets. The results of analyses are compared statistically with those of the author's spectrophotometric method, which confirmed that there is no significant difference between the methods compared.     

A New Validated Potentiometric Method for Batch and Continuous Quality Control Monitoring of Oseltamivir Phosphate (Taminil) in Drug Formulations and Biological Fluids

A new validated potentiometric method is described for batch and continuous quality control monitoring of the drug oseltamivir phosphate (Taminil) (OST). The method involves the development of a potentiometric sensor responsive to the drug based on the use of the ion‐association complex of (OST⁺) cation with phosphomolybdate anion (PMA^?) as an electroactive material in a poly(vinyl chloride) matrix membrane plasticized with o‐nitrophenyloctyl ether (o‐NPOE). Optimization of the performance characteristics of the sensor is described. A membrane incorporating the OST‐PMA‐NPOE complex in a tubular flow through detector is used in a two channel flow injection set up for continuous monitoring of the drug at a frequency of ～30 samples h^?1. The sensor shows fast near‐Nernstian response for OST over the concentration range 5.2×10^?5–0.8×10^?2 M (21.34 µg mL^?1–3.23 mg mL^?1) with a detection limit of 9.1×10^?6 M (3.73 µg mL^?1) over the pH range 4.6–6.1. The sensor displays good selectivity for OST drug over some basic drugs, inorganic cations, excipients and diluents commonly used in the drug formulations. Validation of the assay method is tested by measuring the lower detection limit, range, linearity, bias, trueness, accuracy, precision, and between‐day‐variability, within day reproducibility, selectivity and ruggedness (robustness). The results reveal good potentiometric performance of the proposed sensor for determination of OST in pharmaceutical capsules and in biological fluid matrices as well as for testing the dissolution profile of the drug and drug homogeneity.     

Kinetic Spectrophotometric Determination of Metoprolol Tartrate in Commercial Dosage Forms

A kinetic spectrophotometric method has been described for the determination of metoprolol tartrate in commercial dosage forms. The procedure is based on the reaction of the drug with 1‐chloro‐2, 4‐dinitrobenzene (CDNB) in dimethylsulfoxide (DMSO) at 100 ± 1 °C. The reaction is investigated by measuring the change in absorbance with time at 420 nm. Fixed‐time (ΔA) and equilibrium methods are chosen for obtaining the calibration curves. Both calibration curves were found to be linear over the concentration range of 5‐60 μg mL^?1. The regression analysis of calibration data resulted in the linear regression equations of ΔA = ?1.608 × 10^?4 + 3.96 × 10^?3 C and A = 7.31 × 10^?4 + 1.90 × 10^?2 C for fixed time (ΔA) and equilibrium methods, respectively. The limit of detection (LOD) for fixed time and equilibrium methods are 1.16 and 0.415 μg mL^?1, respectively. The method has been successfully applied to the quantitation of metoprolol tartrate in commercial dosage forms. Statistical comparison of the results shows that there is no significant difference between the proposed methods and El‐Ries's spectrophotometric method.     

Synthesis,characterization, molecular docking,biological activity and density functional theory studies of novel 1,4‐naphthoquinone derivatives and Pd(II), Ni(II) and Co(II) complexes

Two novel heterocyclic ligands, 2‐[(5‐fluoro‐1,3‐benzothiazol‐2‐yl)amino]naphthalene‐1,4‐dione (HL¹) and 2‐[(5‐methyl‐1,3‐benzothiazol‐2‐yl)amino]naphthalene‐1,4‐dione (HL²), and their Pd(II), Ni(II) and Co(II) complexes were prepared and characterized using ¹H NMR, ¹³C NMR, infrared and UV–visible spectroscopic techniques, elemental analysis, magnetic susceptibility, thermogravimetry and molar conductance measurements. The infrared spectral data showed that the chelation behaviours of the ligands towards the transition metal ions were through one of the carbonyl oxygen and deprotonated nitrogen atom of the secondary amine group. Molar conductance results confirmed that the complexes are non‐electrolytes in dimethylsulfoxide. The geometries of the complexes were deduced from magnetic susceptibility and UV–visible spectroscopic results. Second‐order perturbation analysis using density functional theory calculation revealed a stronger intermolecular charge transfer between ligand and metal ion in [NiL¹(H₂O)₂(CH₃COO‐)] and CoL¹ compared to the other complexes. The in vitro antibacterial activity of the compounds against some clinically isolated bacteria strains showed varied activities. [NiL¹(H₂O)₂(CH₃COO‐)] exhibited the best antibacterial results with a minimum inhibitory concentration of 50 μg mL^?1. The molecular interactions of the compounds with various drug targets of some bacterial organisms were established in a bid to predict the possible mode of antibacterial action of the compounds. The ferrous ion chelating ability of the ligands indicated that HL¹ is a better Fe²⁺ ion chelator, with an IC₅₀ of 29.79 μg mL^?1, compared to HL² which had an IC₅₀ of 98.26 μg mL^?1.     

Nonextractive Trace Level Simultaneous Determination of Mercury(II) and Zinc(II) in Environmental Samples with 2‐(5‐Bromo‐2‐pyridylazo)‐5‐diethylaminophenol and Cetylpyridinium Chloride

Abstract

A simple, rapid, selective, and sensitive method for the derivative spectrophotometric determination of Hg(II) and its simultaneous determination in the presence of Zn(II) using 2‐(5‐bromo‐2‐pyridylazo)‐5‐diethylaminophenol in the presence of cetylpyridinium chloride, a cationic surfactant, has been developed. The molar absorption coefficient and analytical sensitivity of the 1∶1 Hg(II) complex at 558 nm (λ_max) are 5.78×10⁴ L mol^?1 cm^?1 and 0.67 ng mL^?1, respectively. The detection limit of Hg(II) is 1.40×10^?2 ng mL^?1, and Beer's law is valid in the concentration range 0.05–2.40 µg mL^?1. Overlapping spectral profiles of Hg(II) and Zn(II) complexes in zero‐order mode interfere in their simultaneous determination. However, 0.10–2.00 µg mL^?1 of Hg(II) and 0.065–0.650 µg mL^?1 of Zn(II), when present together, can be simultaneously determined at zero cross point of the derivative spectrum, without any prior separation. The relative standard deviation for six replicate measurements of solutions containing 0.134 µg mL^?1 of Hg(II) and 0.620 µg mL^?1 of Zn(II) is 1.72 and 1.47%, respectively. The proposed method has successfully been evaluated for trace level simultaneous determination of Hg(II) and Zn(II) in environmental samples.     

Spectrophotometric Determination of U(VI) with Rifampicin in Soil Samples

A validated spectrophotometric method has been developed for the determination of uranyl ion in soil samples. The method is based on the complexation reaction between uranyl ion and rifampicin in methanol‐water medium at room temperature. The method is followed spectrophotometrically by measuring the absorbance at 375 nm. Under the optimized experimental conditions, Beer's law is obeyed in the concentration range of 1.35–20.25 μg mL^‐1 with apparent molar absorptivity and Sandell's sensitivity of 8.0 × 10³ L mol^‐1cm^‐1 and 0.042 μg/cm²/0.001 absorbance unit, respectively. The interference of a large number of anions and cations has been investigated and the optimized conditions developed have been utilized for the determination of uranium(VI) in soil samples. The three sigma detection limit (n = 9) for uranyl ion was found to be 0.20 μg mL^‐1. The proposed method was successfully applied to the determination of uranyl ion in soil samples.