Selective Spectrophotometric Method For Determination Research Articles

A SIMPLE AND SELECTIVE SPECTROPHOTOMETRIC METHOD FOR DETERMINATION OF ETHYL CENTRALITE AS STABILIZER IN DOUBLE BASE SOLID PROPELLANTS: A COMPARATIVE STUDY WITH HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

A SIMPLE AND SELECTIVE SPECTROPHOTOMETRIC METHOD FOR DETERMINATION OF ETHYL CENTRALITE AS STABILIZER IN DOUBLE BASE SOLID PROPELLANTS: A COMPARATIVE STUDY WITH HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

Novel spectrophotometric method for selective determination of compounds in ternary mixtures (dual wavelength in ratio spectra)

A simple selective spectrophotometric method for determination of compounds in ternary mixture was developed by combining the resolution power of two well-known methods that are commonly used for binary mixtures; namely ratio difference method and dual wavelength. The new method (dual wavelength in ratio spectra) was successfully applied for the determination of a ternary mixture of betamethasone dipropionate (BM), clotrimazole (CT) and benzyl alcohol (BA) in pure powder form and in their pharmaceutical preparation. The difference in amplitudes (ΔP) in the ratio spectra at 252.0 and 258.0nm (ΔP252.0–258.0nm) corresponds to BM, while ΔP266.8–255.4nm and ΔP254.2–243.5nm corresponds to CT and BA, respectively. The method was validated as per the USP 2005 guidelines. The developed method can be used in quality control laboratories for routine analysis of compounds in ternary mixtures.

Selective spectrophotometric methods for determination of ternary mixture with overlapping spectra: A comparative study

Comparable double divisor ratio spectra derivative, area under curve of derivative ratio and mean centering of ratio spectra spectrophotometric methods were introduced for determination of orphenadrine citrate (ORPH), caffeine (CAF) and aspirin (ASP); a combination for symptomatic relief of mild to moderate pain of acute musculoskeletal disorders; with evident accuracy and precision. The suggested methods have the advantage over the previously published spectrophotometric method for determination of the same combination in that they did not require a preliminary separation step and able to resolve the ternary mixture, with severe overlapping spectra, with competent sensitivity and selectivity. The recommended methods allow the determination of ORPH, CAF and ASP in the range of 2–32, 2–28 and 3–28μgmL−1, respectively. The validity of the proposed methods was examined by analysis of different laboratory prepared mixtures of ORPH, CAF and ASP and assay of their tablet formulation where reliable results were obtained. Statistical analysis between the suggested spectrophotometric methods and the reported HPLC method using student’s-t and F-ratio tests reveals that the suggested methods are as accurate and precise as the reported one.

Direct and selective spectrophotometric method for the determination of vanadium in steel, environmental and biological samples

A simple, direct and selective spectrophotometric method for determination of vanadium is described. The present methodology is based on the strong oxidizing power of vanadium (V). Vanadium (V) selectively oxidizes leucocrystal violet (LCV) to crystal violet in the presence of phosphoric acid. The violet colored dye obtained shows maximum absorbance at 590 nm. Beer's law is obeyed in the concentration range 0.06–0.6 μg ml −1. The molar absorptivity and Sandell's sensitivity are found to be 6.78 × 10 4 l mol −1 cm −1 and 0.0044 μg cm −2, respectively. The proposed method is simple, direct, and sensitive. It has been successfully applied for the determination of vanadium in various environmental, biological and steel samples.

Development of surfactant assisted spectrophotometric method for determination of selenium in waste water samples

A new, simple and highly selective method for spectrophotometric determination of selenium in waste water samples is described. Selenium(IV) oxidizes I − ions into I 2 which subsequently reacts with excess of I − ion in the acidic media to give tri-iodide ions (I 3 −), and it further reacts with cetylpyridinium cation (CP +) to give a violet colored species. The value of molar absorptivity of the ion-associate species in terms of selenium is 1.80 × 10 4 L mol −1 cm −1 at λ max 510 nm. The detection limit of the method is 10 ng mL −1 Se. The calibration curve is linear over 50–1000 ng mL −1 Se with slope, intercept and co-relation coefficient of 0.23, −4.0 × 10 −4 and +0.99, respectively. None of the tested diverse ions interfered in the present method. The method has been tested for the determination of selenium in waste water samples.

고상에서 용액으로 부터 카드뮴 추출과 잔유물 측정

A new sensitive and selective spectrophotometric method for determination of trace amounts of cadmium using a polyvinyl chloride membrane containing bis-(2-ethylhexyl)phthalate as a solid phase extraction medium was investigated. Bis-(2-ethylhexyl)phthalate has used as a plasticizer. Cd(II) in an aqueous solution was trapped on the membrane in the form of colorful Cd (II)-I- MG complexes (which MG is malachite green) and the cadmium complex was concentrated in the membrane. The absorbance of the green membrane was measured at 629 nm using a spectrophotometer, and then, the concentration of the cadmium was calculated using a calibration curve, which expressed the relationship between the Cd(II) concentration and the membrane absorbance after coloring for 25 min. The calibration curve was linear in the range of 10-760 μgL -1 cadmium in the test solution. The detection limit based on the 3S b1 criterion was 1.8199 μgL -1 and the relative standard deviations (RSD) were less than 4 % (n=5). The proposed method has been successfully applied to the determination of trace amounts of cadmium in the Tadjan River water sample (Sari-Iran), and the mean value of 28.7 μgL -1 was obtained.

Novel Method for Selective Spectrophotometric Determination of Titanium(IV) with Water Extract of Slippery Elm Leaf as a New Reagent

A novel spectrophotometric method for the determination of titanium(IV) by using a new reagent, water extract of slippery elm leaf is developed. In 0.05 M hydrochloric acid, titanium(IV) reacts with this reagent to form a yellow product. The formed product shows maximum absorbance at 415 nm with a molar absorptivity value of 0.68×104 l mol–1 cm–1 and the method was linear in the 0.2–6 µg ml−1 concentration range. The detection limit value was found to be 0.0131 µg ml−1. The proposed method was simple, low cost, selective, and sensitive. It was applied to the analytic samples with satisfactory results.

A selective spectrophotometric method for determination of rosoxacin antibiotic using sodium nitroprusside as a chromogenic reagent

A selective spectrophotometric method for the determination of rosoxacin (ROS), a 4-quinolone antimicrobial agent, has been developed and validated. The method was based on the reaction of ROS with alkaline sodium nitroprusside (SNP) reagent at room temperature forming a red colored chromogen measured at 455 nm. The conditions affecting the reaction (SNP concentration, pH, color-developing time, temperature, diluting solvent and chromogen stability time) were optimized. Under the optimum conditions, good linear relationship ( r = 0.9987) was obtained between the absorbance and the concentration of ROS in the range of 20–50 μg ml −1. The assay limits of detection and quantitation were 2.5 and 8.4 μg ml −1, respectively. The method was successfully applied to the analysis of bulk drug and laboratory-prepared tablets; the mean percentage recoveries were 100.1 ± 0.33 and 101.24 ± 1.28%, respectively. The results were compared favourably with those obtained by the reported method; no significant difference in the accuracy and precision as revealed by the accepted values of t- and F-tests, respectively. The robustness and ruggedness of the method was checked and satisfactory results were obtained. The proposed method was found to be highly selective for ROS among the fluoroquinolone antibiotics. The reaction mechanism was proposed and it proceeded in two steps; the formation of nitroferrocyanide by the action of sodium hydroxide alkalinity on SNP and the subsequent formation of the colored nitrosyl-ROS derivative by the attack at position 6 of ROS.

Spectrophotometric determination of trace lead in water after preconcentration using mercaptosephadex

A highly sensitive and selective spectrophotometric method for determination of trace lead in water after pre-concentration using mercaptosephadex (MS-50) has been developed, the method based on the color reaction of lead(II) with dibromohydroxylphenylporphyrin. Under optimal condition, lead(II) reacts with the reagent to form a 1:2 yellow complex in presence of TritonX-100, which has a maximum absorption peak at 479 nm. The color reaction can complete rapidly and remain stable for 24 h in room temperature. The molar absorption coefficient of the lead complex, the limit of quantification, the limit of detection and relative standard deviations were found to be 2.35×10 5 l mol −1 cm −1, 4.3, 1.4 ng ml −1 and 1.0%, respectively. The absorbance of the lead complex at 479 nm is linear up to 0.48 μg ml −1 of lead(II). The effect of various co-existing ions in water were examined seriously. No interference was observed. Moreover, a simple pre-concentration method for trace lead in water was also studied using MS-50. It was found that trace lead in water can be adsorbed in 1.0 mol l −1 HCl and dissociated from MS-50 with 4.0 mol l −1 HCl quantitatively, that improves the selectivity and the sensitivity of method (its detection limit (3 s) changed into 0.2 ng ml −1 of lead) obviously. The proposed method has been applied to determine trace lead in water samples with satisfactory results.

Highly sensitive and selective spectrophotometric method for determination of trace gold in geological samples with 5-(2-hydroxy-5-nitrophenylazo)rhodanine.

A excellent sensitive and selective method for spectrophotometric determination of trace gold has been developed, the method is based on the color reaction of gold(III) with new reagent 5-(2-hydroxy-5-nitrophenylazo)rhodanine (HNAR). Under optimal conditions, HNAR reacts with gold(III) to form a 1:5 orange complex, which has an maximum absorption peak at 480 nm. Maximum enhancement of the absorbance of the complex was obtained in the presence of the mixed surfactant of Triton X-100 and CTMAB; the reaction completed rapidly and the absorbance is stable for 5 h at least at 20 degrees C; 0-48 microg L(-1) Au(III) obeyed Beer's law. The apparent molar absorptivity of the complex, Sandell's sensitivity, the limit of quantification, the limit of detection and relative standard deviation were found to be 2.0x10(6) L mol(-1) cm(-1), 0.000,098,483 micro g cm(-2), 1.02 ng mL(-1), 0.35 ng mL(-1) and 1.09%, respectively. The effect of co-existing ions was studied seriously; most metal ions can be tolerated in considerable amounts. Its sensitivity and selectivity are remarkably superior to other reagents in the literature. The proposed method was used successfully to determine trace gold in geological samples. Moreover, the synthesis, characteristics and analytical reaction of HNAR with gold are also described in detail.

Spectrophotometric method for determination of germanium in foods with new color reagent trimethoxylphenylfluorone

A high sensitive and selective spectrophotometric method for determination of germanium has been developed. The method is based on the reaction of germanium with a new reagent trimethoxylphenylfluorone (TMPF) in the presence of Triton X-100. The absorbency of the complex ( λ max=505 nm) increases linearly with concentration up to 0.24 μg ml −1 germanium in aqueous solution with a relative standard deviation (R.S.D.) of 1.02%. The molar absorptivity of the germanium complex, the limit of quantification and limit of detection were found to be 1.7×10 5 l mol −1 cm −1, 0.70 and 0.21 ng ml −1, respectively. The influences of metal ions on the determination of germanium were investigated; all foreign ions studied, could be tolerated in considerable amounts, 50 mg of Ca and Mg, 100 mg of Fe and Al, 60 mg of Ni, 8 mg of Mn and 1.0 mg of Pb do not interfere with the determination of 1.0 μg of germanium, so the selectivity is superior to published methods, especially, with regards to Ti, Zr, Sn, Mo and W, which always interfere with the determination of germanium in other methods. The color reaction system is simple and stable. The reaction of germanium with TMPF is complete within 30 min and the absorbency of the complex remains almost constant for at least 24 h in a phosphoric acid medium. In addition, the synthesis of trimethoxylphenylfluorone and the preconcentration of low germanium concentrations were also investigated in detail. The proposed method has been applied to determine traces of germanium in foods with satisfactory results.

Complex Formation Equilibria of Iron(III) With 2-Hydroxy-3- Pyridinol and 2-Mercapto-3-Pyridinol. Spectrophotometry Determination of Iron(III) In Multivitamins

ABSTRACT The complex equilibria of iron(III) with 2-hydroxy-3-pyridinol (HHP), and 2-mercapto-3-pyridinol (MHP) were studied spectrophotometrically in 40% (v/v) ethanol and an ionic strength of 0.1M (NaCIO4). The complexation reactions were demonstrated and characterized using graphical logarithmic analysis of the absorbance pH-graphs. After considering all the different parameters a simple, rapid, sensitive and selective method for spectrophotometric determination of trace levels of iron(III) was proposed based on the formation of (Fe -MHP) complex at pH 2.5 (λmax = 640 nm, ɛ = l×104 L mol−1 cm−). The interference of a large number of foreign ions was investigated. The method has been applied successfully for the determination of iron content in some multivitamins with mineral preparations and infant milk products.

Spectrophotometric study of the complexation equilibria of iron(III) with 3-hydroxypicolinic acid and determination of iron in pharmaceutical preparations.

The complexation equilibria of iron(III) with 3-hydroxypicolinic acid (hypa) have been studied spectrophotometrically in 40% (v/v) ethanol-water medium at 25 degrees C and an ionic strength of 0.1 M NaClO4. The equilibria occurring in solution were established and the basic characteristics of the complexes formed were determined. The spectral study of the reaction solutions containing equimolar concentrations or an excess of one component in the pH range 1.5 to 10.5 gave the evidence for the formation of [FeLH]2+, [FeL]+ and [FeL2]- complex species, depending upon the pH of the medium (LH2 symbolising the molecular form of hypa). The possible complex transitions that occur in solution were demonstrated using graphical and logarithmic analysis of the absorbance-pH graphs. A simple, rapid, sensitive and selective method for spectrophotometric determination of trace levels of iron(III) was proposed based on the formation of Fe(hypa)2 complex at pH 5.5 (lambda = 440 nm, epsilon = 1.5 x 10(4) dm3 mol-1 cm-1). The interference of a large number of foreign ions was investigated. The method has been applied successfully to the analysis of multivitamin and mineral preparations containing iron.

Spectrophotometric determination of chromium(III, VI) by use of chromium(III, VI)—Chrome AzurolS—cetylpyridinium bromide—hydroxylamine hydrochloride—zinc(II) system

This paper shows that the sensitivity of the Cr(III, VI)—Chrome Azurol S (CAS)-cetylpyridinium bromide (CPB)—hydroxylamine hydrochloride system can be increased and the wavelength of maximum absorption slightly shifted by addition of zinc(II) and that the analytical data are practically identical for both Cr(III) and Cr(VI), indicating that under the conditions used both initial oxidation states of chromium yield the same final oxidation state, Cr(III). On the basis of the Cr(III, VI)—CAS—CPB—NH 2OH·HCl—Zn systems a new, highly sensitive and selective method for spectrophotometric determination of microamounts of Cr(III, VI) has been developed, with molar absorptivity of 1.27 × 10 5 1. mole −1 . cm −1 for the complex at 620 nm and linear calibration up to 0.4 μg/ml chromium. Various foreign ions do not interfere. The method can be applied to direct determination of chromium in steels.

A selective spectrophotometric method for determination of quercetin in the presence of other flavonoids

A simple, rapid and highly selective method for determination of quercetin in the presence of other flavonoids was developed. The method is based on the oxidation reaction of quercetin in neutral aqueous solution with N-bromosuccinimide (NBS) in the presence of phenol to give a violet chromogen measurable at 510 nm. Beer's law was valid within a concentration range of 2.5–30 μg/ml with a good correlation coefficient ( r = 0.9990). All variables were studied to optimize the reaction conditions. The method is highly selective for quercetin. Other investigated flavonoids do not interfere. Mixtures of flavonoids were also analysed through native UV measurements of absorbance readings at 370 nm and then at 510 mn after adopting the proposed procedure. The method could also be utilized for the quantitative determination of quercetin in some plant extracts. Moreover, the proposed procedure could be considered as a good tool to follow the hydrolysis of quercetin glycosides.

Extraction-spectrophotometric determination of uranium(VI) with PAR and N-octylacetamide

A new and simple method for selective spectrophotometric determination of uranium(VI) with 4-(2-pyridylazo)resorcinol (PAR) and N-octylacetamide into benzene over pH 7.0–9.0 is described. The molar absorptivity of the complex with 9 different amides is in the range of (0.40–3.2)·104 1·mol−1·cm−1 at the absorption maximum. Out of these, the most sensitive compound N-octylacetamide (OAA) was chosen for detailed studies in the present investigation. The detection limit of the method is 0.008 μg U·ml−1. The system obeys Beer's law in the range of 0–5 μg U·ml−1. The method is free from interferences of most of the common metal ions except vanadium(V) and copper(II), which are masked by proper masking agents. The composition of the complex is determined by curve-fitting method. The method has been applied for the recovery of the metal from rock samples and synthetic mixtures.

Novel Flow Injection Method for Selective Spectrophotometric Determination of Acetylcholine Using Thermochromism of Ion Associates

Abstract A selective and rapid spectrophotometric method for the determination of acetylcholine has been developed by flow injection technique coupled with ion pair extraction using tetrabromophenolphthalein ethyl ester dichloroethane solution, where selectivity can be improved by using both higher pH(pH 11) on extraction and thermochromism of ion associates in a flow system.

A selective spectrophotometric method for determination of copper with ferron

A selective spectrophotometric determination of copper is based on extraction of the copper—ferron complex with tribenzylamine in chloroform at low acidity, and measurement of the absorbance of the yellow extract at 410 nm. Beer's law is found to hold up to 8 μg/ml copper concentration. Of 30 elements tested, only molybdenum interferes. The ratio copper:ferron:tribenzylamine in the extracted species is 1:2:2.

Determination of molybdenum by extraction of its thiocyanate into ethyl methyl ketone

A simple, sensitive and selective spectrophotometric method for determination of molybdenum is described. A solution containing 100 μg of Mo in 2.5 M hydrochloric acid is treated with ascorbic acid and ammonium thiocyanate and after standing for 8 min is shaken with an equal volume of ethyl methyl ketone for 30 sec. The absorbance of the complex is measured at 465 nm against a reagent blank. The complex is stable for 1 hour. There is no interference from Re(VII), SO 2− 4, Cl −, CH 3COO −, PO 3− 4, NO − 3, C 2O 2− 4, citrate or tartrate, and at least 5 mg of U(VI), 10 mg of Cr(III, VI), Th, or Ni, and 20 mg of W(VI) Can be tolerated. Vanadium(V) interferes at the 500 μg level, and fluoride slightly decreases the absorbance.

Spectrophotometric determination of vanadium(v) and its application to vanadium steels containing chromium, molybdenum, tungsten and manganese

A newly synthesized reagent, N- o-toluoyl- N- o-tolylhydroxylamine is used in a sensitive and selective spectrophotometric method for determination of vanadium(V). The method has been successfully applied to vanadium determination in Mn-Mo-Cr-V steels. The system in 2–6 M hydrochloric acid medium obeys Beer's law at 510 nm in the range of vanadium concentration from 0.5 to 10.0 μg ml .