Direct Spectrophotometric Determination Research Articles

Simultaneous spectrophotometric and chromatographic determination of Ketorolac and Dexamethasone: Overall assessment regarding environmental Impact, Practicality, and functionality principles

Determination of a drug combination that contains a minor component that is also a poorly UV absorbing analyte represents greet challenges in drug analysis. A fixed-dose ophthalmic combination of ketorolac tromethamine (KET) and dexamethasone sodium phosphate (DEX) (in the ratio of 5:1) is used to relieve post-surgical inflammation and seasonal allergic conjunctivitis due to their analgesic and anti-inflammatory activity. Five spectrophotometric methods and a reversed phase chromatographic separation method were developed and validated for simultaneous determination of both drugs in lab-prepared eye drops. Direct spectrophotometric determination of KET (the major, highly UV absorbing analyte) was achieved from the zero-order UV absorption spectra at 323 nm while DEX (which is the minor, poorly UV absorbing analyte) was quantified after applying several spectrophotometric methods. Either fundamental zero-order spectra or ratio spectra were used, and measurements were done at either single or dual wavelengths. The developed methods were: isosbestic point method, absorption factor method, dual wavelength method, ratio difference UV spectrophotometric method, and simultaneous equation method. The developed spectrophotometric methods determine KET in the linearity range of 2.0–12.0 μg/mL and DEX in the range of 5.0 – 35.0 μg/mL. For accurate spectrophotometric determination of DEX in the ratio of the dosage form, multiple standard addition method was applied. HPLC technique was also applied for separation and quantification of both drugs. Chromatographic separation was attained by using Hypersil ODS-C18 (150 x 4.6 mm, 5 μm) column. The mobile phase was composed of 50 % methanol: 50 % phosphate buffer (pH 2.5). The column compartment was maintained at 25 °C. Flow rate was adjusted at 1.2 mL/min and detection was performed by DAD at 254 nm. The linearity of HPLC method was 5.0–100.0 μg/mL, and 5.0–50.0 μg/mL for KET and DEX, respectively. Simultaneous determination of both drugs was applied to lab-prepared eye drops that contain also benzalkonium chloride as inactive ingredient. The developed methods determined the cited drugs with good and acceptable % recovery. The results of the developed methods and a reported HPLC method were compared using one-way ANOVA test, F-test and student’s t-test at confidence level 95 %, and they show no significant statistical difference. Assessment of greenness of the developed methods in comparison with reported HPLC method was performed using different tools, including analytical eco-scale, GAPI and AGREE. HPLC-EAT was also performed to ensure greenness of developed HPLC method. Moreover, assessment of practicality, applicability, and functionality of developed and reported methods was evaluated by BAGI metric tool and WAC calculator, respectively. The developed methods allow simple, rapid, and accurate analysis of quality control samples that contain KET and DEX.

Comparative Studies on Spectrophotometric Determination of Selected Heavy Metals in Environmental and Biological Samples with Synthetic Phenylhydrazones as Chromogenic Reagents

This work involves a comparative study on a simple, sensitive, selective and non-extractive Uv- Vis spectrophotometric method for the determination of cadmium, lead, chromium and arsenic in biological, soil and water samples using synthesized and characterized phenylhydrazones; [glutaraldehyde phenylhydrazone (GPH) and acetylpyridine-2,4-dinitrophenylhydrazone (APDH)] as the chromogenic reagents was developed. GPH and APDH were synthesized as new chromogenic analytical reagents for the direct UV-Vis spectrophotometric determination of the selected metals of interest in a slightly acidic pH of 6.5-7.5 and 20% dimethylformamide (DMF) solution to give stable coloured metal-ligand complexes. The reactions were instantaneous; the wavelengths of maximum absorptions were followed spctrophometrically and noted. The analytical properties of the reagent APGH on the metals (Cd, As, Pb, and Cr) revealed the wavelength of maximum absorption ranged between 385.0 (Cr) to 440.0nm for (Pb). The reagent APDH had molar absorptivities (L mol -1 cm -1 ) ranging from 2.006 x 10 4 (Pb) to 2.407 x 10 4 (Cd), a mole ratio of metal to ligand of 1:1, a detection limit (µg/g) ranging from 0.3272 (As) to 0.4456 (Cd) and the metal-ligand complex was stable for 0-36 hours. The reagent GPH revealed a wavelength of maximum absorption between 360.0 (Cr) to 395.0 nm for (Pb and As) at a working pH of 6.5 to 7.5 room temperature (37°C). The reagent GPH had a molar absorptivities (L mol -1 cm -1 ) ranging from 2.213 x 10 4 (Pb) to 2.460 x 10 4 (As), a mole ratio of metal to ligand of 2:1, the detection limit (µg/g) ranging from 0.3432 (As) to 0.5250 (Pb) and the metal-ligand complex was stable for 0-48 hours. Both reagents had a Beer’s law validity range (mgL -1 ) of 0.001 to 100. The Sandell’s sensitivities (µg/cm 2 ) ranged from 0000409 (As) to 0.00499 (Pb) for APDH and 0.00406 (As) to 0.00452 (Pb) respectively. Large excess of cations and anions as possible interferences up to 1

A Green Chemosensing Approach for Direct and Liquid-liquid Extractive Spectrophotometric Determination of Platinum

A Green Chemosensing Approach for Direct and Liquid-liquid Extractive Spectrophotometric Determination of Platinum

Direct and derivative spectrophotometric determination of cobalt(II) with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone

Direct and derivative spectrophotometric determination of cobalt(II) with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone

6,7- AND 7,8-DIHYDROXYBENZOPYRYLIUM DERIVATIVES: SYNTHESIS, PROPERTIES AND ANALYTICAL APPLICATION (REVIEW)

The present review is devoted to a class of organic analytical reagents 6,7- and 7,8-dihydroxybenzopyrylium derivatives: their synthetic pathways, physicochemical properties, state in solutions, and analytical applications are described. Anion nature influence on spectral characteristics and some physico-chemical properties of 6,7-dihydroxybenzopyrylium derivatives was noted. Pathways of acid-base transformations in aqueous solutions of 6,7-dihydroxybenzopyrylium derivatives were described. It has been shown that derivatives of 6,7- and 7,8-dihydroxybenzopyrylium are capable for complexation with a number of p-, d-, and f-elements (Cu (II), Ga (III), In (III), Tl (III), Ge (IV), La (III), titanium subgroup, Bi (III), Mo (VI), W(VI) and others). Information on their composition, structure and analytical characteristics is summarized. It is noted that with the 6,7-dihydroxybenzopyrylium derivatives the simple and highly sensitive methods for the direct spectrophotometric and extraction-photometric determination of Ga(III), In(III), Tl(III), Ti(IV), Zr(IV), Hf(IV), Mo(VI), Ge(IV), Bi(III), Cu(II) have been developed. It is noted that 6,7-dihydroxybenzopyrilium derivatives complexes with Mo(VI) and Cu(II) are effectively extracted by Triton X‑100 micellar phase, which forms the basis for highly sensitive combined spectrophotometric and atomic absorption methods for their determination. The simplicity of targeted synthesis of 7,8- and 6,7-dihydroxybenzopyrylium derivatives opens the way to their use in the development of combined cloud point extraction and liquid-liquid microextraction with spectrophotometric or atomic absorption detection methods for the determination of a number of p- and d-elements.

UV-Vis Spectrophotometric Determination of Selected Heavy Metals (Pb, Cr, Cd and As) in Environmental, Water and Biological Samples with Synthesized Glutaraldehyde Phenyl Hydrazone as the Chromogenic Reagent

A simple, sensitive, selective, and non-extractive UV-Vis spectrophotometric method for the determination of cadmium, lead, chromium, and arsenic in biological, soil and water samples using synthesized and characterized phenyl hydrazone; glutaraldehydephenyl hydrazone (GPH) as the chromogenic reagent was developed. GPH was synthesized as new chromogenic analytical reagents for the direct UV-Vis spectrophotometric determination of the selected metals of interest in a slightly acidic pH of 6.5-7.5 and 20 % dimethylformamide (DMF) solution to give stable coloured metal-ligand complexes. The reactions were instantaneous; the wavelengths of maximum absorptions were followed spectrophotometrically and noted. The reagent GPH revealed a wavelength of maximum absorption between 360.0 (Cr) to 395.0 nm for (Pb and As) at a working pH of 6.5 to 7.5 room temperature (37 °C). The reagent GPH had a molar absorptivity (L mol-1 cm-1) ranging from 2.213×104 (Pb) to 2.460×104 (As), a mole ratio of metal to ligand of 2:1, the detection limit (µg/g) ranging from 0.3432 (As) to 0.5250 (Pb) and the metal-ligand complex was stable for 0-48 hours. The reagents had a Beer’s law validity range (mg L-1) of 0.001 to 100. The Sandell’s sensitivities (µg/cm2) ranged from 0000409 (As) to 0.00499 (Pb) for APDH and 0.00406 (As) to 0.00452 (Pb) respectively. Large excess of cations and anions as possible interferences up to 15 folds were studied and do not interfere with the determination of the selected metals of interest. The developed method is highly selective for Cd, Pb, and Cr and As and was successfully used for the determination for the said elements in soil, water, and biological samples. The results of the developed methods were comparable with AAS and were found to be in good agreement. The method had very high precision and very good accuracy.

4, 4’-Diantipyrylmethane (DAM): A tool for spectrophotometric microdetermination of cerium (IV)

A simple and hasty method has been employed for the direct spectrophotometric determination of trace amount of Ce(IV) using a complexing agent 4,4’-diantipyryl methane (DAM) with absorption maximum at 445-455nm in acidic medium at 1.3 -1.5 pH. Molar absorptivity and Sandell’s sensitivity were calculated to be 9.1 × 103 l mol-1 cm-1 and 0.015 μg Ce cm-2. Beer’s law was found to be defensible over the cerium concentration range of 0-5.5 μg ml-1. Effect of large number of cations, anions and complexing agents was also studied and several analytically important ions do not cause interference in the procedure except thiourea and EDTA. The method has good reproducibility and has been satisfactorily applied in the determination of cerium in samples.

Direct solid-phase spectrophotometric determination of tartrazine in soft drinks using β-cyclodextrin polymer as support

A sensitive and new solid-phase spectrophotometry for the determination of tartrazine in soft drinks has been developed. In this method, β-cyclodextrin epichlorohydrin polymer (β-CDP) of 60-80 mesh, which has less background absorbance in ultraviolet and visible region compared to other ion-exchanger resins, was used to support direct adsorption of tartrazine from aqueous solutions to form a solid complex (tartrazine-β-CDP complex). The effects of pH, temperature, time and ionic strength on the β-CDP including tartrazine were determined. The optimum conditions were obtained (pH, 1.0; temperature, 20℃; time, 40 min). The method was applied for the direct solid phase spectrophotometric determination of tartrazine in soft drink samples at the maximum absorption wavelength of 435 nm with satisfactory results.

Validated spectrophotometric determination of maduramicin ammonium using three charge transfer complexation reactions

Direct spectrophotometric determination of Maduramicin ammonium (MAD) represents an analytical challenge since it is a weak UV-absorbing and lacking a strong chromophore. This work represents the first spectrophotometric determination of MAD as no direct spectrophotometric or colorimetric determination methods for MAD are available in the literature. The present study illustrates the development of three simple, rapid and inexpensive colorimetric methods for the routine quality control analysis of MAD based on the formation of colored charge transfer complexes with three electron acceptors namely p-chloranilic acid (p-CA), 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and picric acid (PA). The color products of MAD with p-CA, DDQ and PA were measured at 519, 588 and 405nm respectively. The proposed methods were validated in terms of linearity, ranges, precision, accuracy, robustness and limits of detection and quantification. MAD was effectively determined over concentration ranges of 100-1000, 25-250 and 30-150μg/mL using p-CA, DDQ and PA, respectively with good linearity as shown by the values of correlation coefficients not less than 0.9991. The developed methods were successfully implemented in the assay of MAD powder pharmaceutical formulation for veterinary use.

Analytical quantification of aqueous permanganate: Direct and indirect spectrophotometric determination for water treatment processes

Three spectrophotometric methods have been developed and compared for the quantification of low concentrations (0.03–63 μM) of aqueous permanganate in neutral pH conditions. Although permanganate is a widely used oxidant in drinking water and wastewater treatment, no widely accepted method of quantification has been reported to date. While one method presented does not require the need for any reagent chemicals (direct spectrophotometric analysis), it yielded a relatively low molar absorption coefficient of 3340 M−1 cm−1 at 525 nm and a level of detection (LOD) and quantification (LOQ) of 0.45 and 1.51 μM, respectively. Some instability of permanganate species during direct quantification was found to occur over 60 min, with a total decrease of 0.002 (arbitrary units) of absorbance, equivalent to a decrease in concentration of 0.6 μM. Beyond 60 min, no further degradation was observed. Indirect spectrophotometric analyses using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and sodium iodide (NaI) provided a significantly more sensitive method for permanganate quantification, yielding molar absorption coefficients of 140,030 and 61,130 M−1 cm−1, respectively. The LOD and LOQ were determined to be 0.01 and 0.03 μM for the ABTS method and 0.02 and 0.08 μM for the NaI method, respectively. Although conservative and accurate limits of quantification for both the ABTS and NaI methods are presented, which should be sufficient of most practical applications, lower limits may be possible with further refinement of the methods.

ВИЗНАЧЕННЯ КЕТОПРОФЕНУ І ЦЕФТІОФУРУ У ВЕТЕРИНАРНИХ ПРЕПАРАТАХ СПЕКТРОФОТОМЕТРИЧНИМ МЕТОДОМ

Мета роботи. Розробка методики визначення кетопрофену та цефтіофуру в комбінованих ветеринарних препаратах спектрофотометричним методом.
 Матеріали і методи. Ветеринарні препарати «Процефен-100» і «Коцефен-200» (ТОВ «Ветсинтез», Харків, Україна). У роботі використовували стандартні зразки кетопрофену та цефтіофуру і допоміжних речовин фармакопейної чистоти (Sigma-Aldrich). Спектрофотометричні (СФ) вимірювання проводили на скануючому спектрофотометрі CARY.WIN – UV-VIS-50 (Varian, США) у кварцових кюветах із товщиною поглинаючого шару l = 1 см.
 Результати й обговорення. Одночасно неможливо визначити цефтіофур та кетопрофен у комбінованих лікарських препаратах прямим спектрофото-метруванням. В електронних спектрах поглинання їхніх модельних сумішей спостерігається перекривання максимумів визначуваних речовин. Експериментально підібрані умови їхнього розділення для наступного визначення прямим спектрофотометруванням. Оптимальним розчинником виявився дихлорметан, у якому кетопрофен розчиняється, тоді як цефтіофур залишається нерозчинним. Для розчинення цефтіофуру використовували етанол 96 %. Наявність допоміжних речовин не впливає на спектральні характеристики визначуваних речовин, що було показано при аналізі модельних сумішей препаратів із допоміжними речовинами та без них. Методика полягає у вилученні кетопрофену дихлорметаном і його прямому спектрофотометричному визначенні за довжини хвилі 254 нм, а також прямому спектрофотометричному визначенні цефтіофуру, вилученого етанолом, за довжини хвилі λ = 290 нм.
 Висновки. Встановлено умови розділення субстанцій кетопрофену та цефтіофуру, на основі чого розроблено методику розділення та кількісного спектрофотометричного визначення у двох комбінованих ветеринарних препаратах із різним співвідношенням визначуваних речовин. Розраховано метрологічні характеристики методики, а отримані результати кількісного визначення кетопрофену і цефтіофуру статистично не відрізняються від результатів отриманих заметодикою ВЕРХ (за F- та t-критеріями).

Development of a Technique for Codetermination of Tannin and Gallic Acid in Medicinal Plant Raw Material

Development and validation of a new technique for direct spectrophotometric quantitative determination of high- and low-molecular-mass tannins are reported. The proposed method enables simultaneous codetermination using Firordt calculations of tannins and gallic acid in medicinal plant raw material and herbal preparations without preliminary separation from complicated mixtures with other biologically active compounds found in the plant extracts. The developed method was validated (using nettle raw material as an example). The contents of gallic acid and tannins in the samples were (1.20 ± 0.04)% and (1.52 ± 0.03)%, respectively, which agreed with literature data.

Разработка методики определения танина и галловой кислоты при совместном присутствии в лекарственном растительном сырье

Представлены результаты разработки и валидации новой методики прямого спектрофотометрического количественного определения высокомолекулярных и низкомолекулярных дубильных веществ. Предложенная методика дает возможность одновременного определения танина и галловой кислоты при совместном присутствии в лекарственном растительном сырье и лекарственных растительных препаратах без предварительного разделения в сложных смесях с другими биологически активными веществами, присутствующими в вытяжках из растительного сырья, с применением расчетного метода Фирордта. Проведена валидационная оценка (на примере сырья крапивы двудомной) разработанной методики. Содержание галловой кислоты и танина в образцах составило (1,20 ± 0,04) % и (1,52 ± 0,03) % соответственно, что согласуется с данными литературы.

Direct Spectrophotometric Determination of Cefuroxime Axetil in Pure Form and Pharmaceutical Dosage Forms.

A simple, direct and cost-effective spectrophotometric method for determination of cefuroxime axetil (CRXA) in pure and tablet dosage forms was applied. This method is based on formation of ion-pair complex ([CRXA]:[BTB]) between CRXA and bromothymol blue (BTB) in chloroform. Beer’s law in the optimum experimental conditions using [CRXA]:[BTB] complex is valid within a concentration range of 2.00-50.00 ?M (1.021–25.524 ?g.mL-1). The developed method is applied for the determination of CRXA in pure and its commercial tablets without any interference from excipients with average assay of 96.8 to 101.6% and the results are in good agreement with those obtained by the HPLC reference method. Associated drugs (sulbactam and linesolid) with cefuroxime axetil are considered to be interfere, while metronidazole can be considered as non-interfere.

Application of different analytical techniques for determination of velpatsvir and sofosbuvir in the pharmaceutical preparation

Three analytical methods have been developed and applied for determination of velapatasvir and sofosbuvir in their new FDA-approved pharmaceutical dosage form. Capillary electrophoresis has been introduced as a powerful separation analytical technique for the simultaneous analysis of the studied drugs within a shorter analytical run time. Separation has been carried out on fused silica capillary (50 cm × 75 µm internal diameter), background electrolyte solution consisted of borate buffer (40 mM, pH 10) and UV detection carried out at 225 nm. Also, two mathematical spectrophotometric methods have been applied for resolving the recorded overlapping UV spectra of velpatasvir and sofosbuvir. Direct zero-order spectrophotometric determination of velpatasvir was done at 339 nm where no significance absorbance or contribution from sofosbuvir was observed. Savitsky–Golay filters signal processing has been achieved to enable determination of sofosbuvir in its binary mixture with velpatasvir. The amplitude of the first derivative of the sofosbuvir spectra, calculated by Savitsky–Golay filters, at 251 nm enabled the determination of sofosbuvir without any contribution of velpatasvir. The described methods have been validated and applied for determination of the studied drugs in their pharmaceutical dosage form.

Green in-Line Ion Selective Electrode Potentiometric Method for Determination of Amantadine in Dissolution Media and in Pharmaceutical Formulations

Amantadine HCl (AMN) is a well-known antiviral agent. Chemically, AMN chromophore privation leads to the absence of UV-absorbance, a condition that hinders direct spectrophotometric or simple chromatographic determination using common detectors without prior derivatization steps. In this work, an environmentally friendly ion selective electrode (ISE) method was developed for the determination of AMN, and measurements were carried out directly in the aqueous solution of the sample without pretreatment or derivatization steps. PVC-membranes were fabricated using nitrophenyl octyl ether as a plasticizer along with different cation exchangers, responses were compared, and that containing phosphomolybdic acid proved to have the best near-Nernstian slope through a wide linear range (4.57 × 10–7)–(1.0 × 10–2) M. The ion pair was obtained by soaking the membrane sensor in a 1 × 10–2 M solution of AMN. The sensor was able to determine AMN in colored and turbid solutions of its tablets and capsules without prior ex...

Direct Spectrophotometric Determination of Lead (II) in Industrial Samples using 1, 3-Benzenediamine, N, N'-bis(2-furanylmethylene) in Presence of Surfactant

Schiff's base are one of the excellent chelating agents that used for the spectrophotometric determination of metal ions. It was observed that 1, 3-Benzenediamine, N,N'-bis(2-furanylmethylene) (BDFM) formed a brown colored complex with lead (II) at 620 nm. Lead (II) was chelated with the Schiff's base (BDFM) in acidic medium at pH = 3.5 using acetate buffer in presence of sodium laureth sulfate (SLS) as a surfactant. The effect of time, temperature and foreign ions were studied. The stoichiometric composition of the formed complex was found to be 1:2 (metal: ligand) by Job's method of continuous variation. Beer's law was obeyed in the range of 10-110 μg mL-1 with molar absorptivity 10.16×103 L mol-1cm-1. The proposed method was applied for the determination of lead in gasoline, solders, gutters and wastewater.

RESEARCH METHODOLOGY OF SUS SCROFA TISSUE EXTRACTS PROTEIN-PEPTIDE COMPONENTS

The article presents a comparative analysis of four methods for quantifying the protein-peptide complexes content in extracts obtained from animal raw materials, as well as the low- and highmolecular weight extract fractions: the direct spectrophotometric determination at wavelengths of 260 and 280 nm with subsequent calculation by the Kalckar formula; the biuret reaction by the Kingsley-Weichselbaum method; the method with Bradford reagent and the standard Lowry method. Experimental data analysis demonstrates that in case of the extract that contains protein-peptidic complexes in different molecular weights range, the Kingsley-Weichselbaum method shows the highest quality of protein concentration determination; while studying highmolecular weight fraction (more than 30 kDa), it is possible to obtain more information by combining the spectrophotometric method and the Kingsley-Weichselbaum method. Low-molecular weight fractions (less than 30 kD) should be investigated by complex methods including the spectrophotometric method, Lowry and Bradford methods. These methods make it possible to presumably estimate protein molecules size ranges (by amount of peptide bonds), and also to determine hydrophobic and aromatic amino acids presence.

A low cost and rapid analytical technique for direct spectrophotometric determination of chromium in V–Cr–Ti alloys without a chromogenic agent

A simple, rapid and accurate spectrophotometric method was developed for the determination of chromium in V–Cr–Ti ternary alloy without any prior separation and chromogenic agent.

Direct Spectrophotometric Determination of Sildenafil Citrate in Pharmaceutical Preparations Via Complex Formation with Two sulphonphthalein acid dyes

Objective: Simple, sensitive and free- extraction spectrophotometric methods have been developed for the determination of Sildenafil citrate (SIL) both in pure and in pharmaceutical forms. Methods: Two spectrophotometric methods are based on the formation of yellow colored ion-pair complexes between the studied drug and two sulphonphthalein acid dyes, bromocresol green (BCG)(method A) and bromothymol blue (BTB) (method B) with absorption maxima at 414 and 409 nm, respectively. Results: The effects of analytical parameters on the reported systems were investigated. The complexation reactions were extremely rapid at room temperature and t¬he absorption values remain unchanged up to 24h. Various analytical parameters have been evaluated and the results have been validated by statistical. Beer’s law was obeyed in the concentration ranges of (1.33 – 50) µg/ml for method A and (0.8 -27) µg/ml for method B, the limits of detection were 0.093 and 0.059 µg/ml and the molar absorptivity coefficients were 2.28×104 and 3.05 ×104 L .moL-1.cm-1 for method A and B respectively. Conclusion: The proposed methods were successfully applied to the analysis of commercial tablets containing the drugs. Two methods were free-extractive, rapid, and have high sensitivity comparing with other previous direct spectrophotometric methods. Interferences of the other ingredients and excipients were not observed.