scholarly journals Masking is the Effective Alternative to the Separation during Osmium Determination by Means of Azo Dyes in Complex Samples

2010 ◽  
Vol 4 (2) ◽  
pp. 115-124
Author(s):  
Mariana Rydchuk ◽  
◽  
Teodoziya Vrublevska ◽  
Mariya Boyko ◽  
Olha Korkuna ◽  
...  
Keyword(s):  
Direct Determination ◽  
Complex Samples ◽  
Spectrophotometric Methods ◽  
Masking Agents ◽  
Platinum Group ◽  
Monoazo Dyes ◽  
Interfering Ions ◽  
Osmium Determination ◽  
Better Than

The selectivity of the spectrophotometric methods for determination of microgram quantities of osmium (IV) with acidic monoazo dyes Tropaeolin O (TpO) and Tropaeolin OOO-I (TpOOOI) in the presence of concomitant metals, particularly platinum group, heavy and rare earths (RE) has been studied. The tolerance ratios of interfering elements have been established. The selectivity of the interaction of TpOOOI with osmium (IV) relatively to platinum group elements (PGEs) is much better than TpO. It has been established that the influence of interfering ions can be easily eliminated by means of masking agents viz. EDTA, tartrate, citrate, pyrophosphate and fluoride, and thereby the selectivity of the methods of osmium determination with TpO and TpOOOI has been sufficiently improved. The methods have been approved during the analyses of various model solutions containing ruthenium, platinum, palladium, rhodium and iridium and the masking reagents. Also osmium content has been determined in the intermetallic alloy Nd20Os15Sі65. The standard deviations did not exceed typical values for spectrophotometric methods (RSDs < 5 %). Thus the elaborated methods with various masking agents may be used for direct determination of osmium in complex samples without any preliminary separation of osmium in the form of OsO4 as well as without the extraction of matrices elements.

Synchronous Luminescence Spectroscopy: Methodology and Applicability

1982 ◽  
Vol 36 (5) ◽  
pp. 576-581 ◽  
Author(s):  
Tuan Vo-Dinh
Keyword(s):  
Direct Determination ◽  
Cost Effective ◽  
Luminescence Spectroscopy ◽  
Second Derivative ◽  
Experimental Conditions ◽  
Complex Samples ◽  
Figures Of Merit ◽  
Synchronous Luminescence Spectroscopy ◽  
Complex Organic

This paper discusses the figures of merit associated with the synchronous luminescence (SL) technique in multicomponent analysis of complex samples. Spectral interferences and experimental factors that influence the choice of experimental conditions are investigated. The efficacy of SL is demonstrated in the direct determination of anthracene and 2-methylanthracene in a raw coal liquid. The application of the second-derivative technique to the SL measurement of organic samples is shown. Special emphasis is directed toward the applicability of the SL technique as a practical and cost-effective screening procedure in the routine analysis of complex organic samples.

Modifications of spectrophotometric methods for total phosphorus determination in meat samples

2009 ◽  
Vol 63 (1) ◽  
Author(s):  
Aneta Jastrzębska
Keyword(s):  
Total Phosphorus ◽  
Reducing Agents ◽  
Statistical Parameters ◽  
Molybdenum Blue ◽  
Spectrophotometric Methods ◽  
Hydrazine Sulphate ◽  
Meat Samples ◽  
Blue Reaction ◽  
Better Than

AbstractSpectrophotometric determination of total phosphorus in meat samples was modified using the molybdenum blue reaction with the following reducing agents: ascorbic acid (AA), hydrazine sulphate (HS), and mixture of hydroquinone and hydrazine sulphate (HHS). Proposed methods were validated by evaluation of statistical parameters such as: linearity, sensitivity, limits of detection (DL) and quantification (QL), precision, and accuracy, against the standard and malachite green (MG) modified procedures and by applying food certified materials. The values of within-day and between-days precision in meat samples for all tested reducing agents were better than 3.4 % and 4.2 %, respectively. The recoveries for CRMs analyses were between 92 % and 102.3 %. Obtained results suggest usefulness of the hydroquinone and hydrazine sulphate mixture in the determination of phosphorus ions.

Fluorometric assay for pancreatic lipase.

1986 ◽  
Vol 32 (8) ◽  
pp. 1532-1536 ◽  
Author(s):  
R Salvayre ◽  
A Nègre ◽  
J Radom ◽  
L Douste-Blazy
Keyword(s):  
Fatty Acids ◽  
Pancreatic Lipase ◽  
Lipase Activity ◽  
Direct Determination ◽  
Normal Subjects ◽  
Fluorometric Assay ◽  
Fluorometric Method ◽  
Turbidimetric Method ◽  
Better Than

Abstract We report a new fluorometric assay in which a fluorescent triglyceride is used for determining lipase activity in serum, and we compare it with turbidimetric and radiometric methods. Because this fluorometric method is at least 50-fold more sensitive than the turbidimetric method, we have been able to develop a micromethod that requires only very small amounts of substrate reagent and serum. The use of fluorescent-labeled fatty acids allows direct determination of the product of lipase action and obviates the use of a standard for calibrating the method. Results of the fluorometric method are well correlated with those of the radiometric and turbidimetric methods, and the precision of the fluorometric assay is better than that of the turbidimetric method. Reference values for normal subjects are between 0 and 120 mU/L.

Direct stopped-flow fluorescence polarization immunoassay of abused drugs and their metabolites in urine

1994 ◽  
Vol 40 (8) ◽  
pp. 1489-1493 ◽  
Author(s):  
D Pérez-Bendito ◽  
A Gómez-Hens ◽  
A Gaikwad
Keyword(s):  
Fluorescence Polarization ◽  
Analytical Data ◽  
Direct Determination ◽  
Stopped Flow ◽  
Fluorescence Polarization Immunoassay ◽  
Polarized Fluorescence ◽  
Abused Drugs ◽  
Assay Precision ◽  
Better Than

Abstract Kinetic methodology was applied to the direct determination of abused drugs (amphetamines, cocaine, and cannabinoids) in urine by stopped-flow fluorescence polarization immunoassay (SF-FPIA). This technique provides analytical data within a few seconds by measuring the variation of polarized fluorescence with time during development of immunochemical reactions. Methods based on this principle are particularly suitable for routine screening of these drugs in urine, being more expeditious than conventional FPIA methods. The dynamic ranges of the calibration curves were 20-300 micrograms/L for d,l-amphetamine, 15-300 micrograms/L for benzoylecgonine (a cocaine metabolite), and 10-400 micrograms/L for 11-nor-delta 8-tetrahydrocannabinol-9-carboxylic acid (a cannabinoid metabolite). The detection limits and within- and between-assay precision were better than those provided by conventional FPIA. Analytical recoveries ranged between 97.5% for d,l-amphetamine and 102.4% for the cannabinoid metabolite. The results for the three analytes were consistent with those obtained by conventional FPIA.

scholarly journals Sensitive spectrophotometric assay of simvastatin in pharmaceuticals using permanganate

2010 ◽  
Vol 46 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Kalsang Tharpa ◽  
Kanakapura Basavaiah ◽  
Nagaraju Rajedraprasad ◽  
Kanakapura Basavaiah Vinay ◽  
Salmara Ganeshbhat Hiriyanna
Keyword(s):  
Optimum Conditions ◽  
Acetic Acid Medium ◽  
Recovery Method ◽  
Spectrophotometric Methods ◽  
Accuracy And Precision ◽  
Ich Guidelines ◽  
Bulk Drug ◽  
Tablet Dosage ◽  
Better Than

Two simple, sensitive, selective and inexpensive spectrophotometric methods are described for the determination of simvastatin (SMT) in bulk drug and in tablets using permanganate as the oxidimetric reagent. In method A, SMT is treated with a measured excess of permanganate in acetic acid medium and the unreacted oxidant is measured at 550 nm, whereas in method B the reaction is carried out in alkaline medium and the resulting manganate is measured at 610 nm. In method A, the amount of permanganate reacted corresponds to the SMT content and the absorbance is found to decrease linearly with the concentration; and in method B, the absorbance increases with concentration. The working conditions of assays were optimized, and the methods were validated according to the current ICH guidelines. Under optimum conditions, SMT could be assayed in the concentration ranges, 1.47 - 17.67x10-5 and 2.27 - 27.18 x10-6 mol/L by method A and method B, respectively. The calculated molar absorptivities are 3.2 x 10³ and 2.5 x 10(4) L/mol/cm for method A and method B, respectively with corresponding Sandell sensitivity values of 0.0387 and 0.0178 μg/cm². The limits of detection (LOD) and quantification (LOQ) have also been reported. Accuracy and precision for the assay were determined by calculating the intra-day and inter-day at three concentrations; the intra-day RSD was < 2% and the accuracy was better than 2.15 % (RE). The methods were applied successfully for the determination of SMT in tablet dosage form with a high percentage of recovery, good accuracy and precision, and without measurable interference by the excipients. The accuracy was further ascertained from placebo and synthetic mixture analysis and also from the spike-recovery method.

Comparison of spectrophotometric methods of determining Fe(III) using a computer-controlled SuperScanR 3 UV-VIS spectrophotometer

1980 ◽  
Vol 45 (6) ◽  
pp. 1793-1804 ◽  
Author(s):  
Dagmar Gotzmannová ◽  
Vlastimil Kubáň
Keyword(s):  
Blood Serum ◽  
Calibration Curve ◽  
Direct Determination ◽  
Spectrophotometric Methods ◽  
Chromazurol S ◽  
Direct Recording ◽  
Basic Parameters ◽  
Computer Controlled

Methods of the direct determination of Fe(III) with Eriochromazurol B, Chromazurol S, Eriochromcyanine R, 4-(2-pyridylazo)resorcinol and 4-(2-thiazolylazo)resorcinol were compared using basic parameters for the spectrophotometric methods. The most useful reagents for determining Fe(III) in blood serum are Chromazurol S and PAR. The possibility of direct recording and treatment of the calibration curve using the SuperScanR 3 spectrophotometer controlled by an HP 9815A desk-top calculator is demonstrated.

scholarly journals Direct determination of piroxicam in pharmaceutical forms using flow injection- spectrophotometry

2020 ◽  
Vol 34 (1) ◽  
pp. 13-23
Author(s):  
Ream Ismail Abed ◽  
Hind Hadi ◽  
Hind Hadi
Keyword(s):  
Flow Injection ◽  
Room Temperature ◽  
Direct Determination ◽  
High Sensitivity ◽  
Experimental Conditions ◽  
Spectrophotometric Methods ◽  
Relative Standard ◽  
Physical Variables ◽  
Orange Color

In this research, direct batch and flow injection (FI) spectrophotometric methods for the analysis of piroxicam (PIX) in commercial dosage forms were investigated. The methods were based on the reaction of PIX with diazotized metoclopramide in alkaline medium to form orange color product at room temperature which absorbs maximally at λmax 472 nm. Chemical and physical variables of batch and FI methods were optimized to produce high sensitivity and reproducibility. Under the optimized experimental conditions, Beer’s law was obeyed over concentration ranges from 1 - 35 and 10 - 250 μg/mL PIX with limits of detection of 0.2 and 3.4 μg/mL and limits of quantification of 0.7 and 11.4 μg/mL PIX for batch and FI procedures, respectively. The relative standard deviation (%RSD) was less than 0.7 and 2.4 for batch and FI procedures respectively with a sample throughput of 38 h-1 for FI procedure. The proposed methods can be used for the routine analysis for the assay of PIX in injections and capsules.   Bull. Chem. Soc. Ethiop. 2020, 34(1), 13-23. DOI: https://dx.doi.org/10.4314/bcse.v34i1.2

A method for the direct determination of the rate constants for radical-radical interactions in the gas phase I. The technique of investigation

1957 ◽  
Vol 243 (1232) ◽  
pp. 119-129 ◽  
Keyword(s):  
Time Delay ◽  
Phase I ◽  
Gas Phase ◽  
Direct Determination ◽  
Pressure Change ◽  
Gas Phase Reactions ◽  
Temperature Changes ◽  
Pressure Changes ◽  
Better Than

A method of following the non-stationary state in simple photochemically initiated gas-phase reactions is described. Measurements are recorded by observing the pressure change occurring in the gas resulting from the adiabatic temperature changes caused by reaction. The pressure changes are observed by means of a sensitive diaphragm type manometer, whose sensitivity in detection is better than 10 -4 mm Hg and whose time delay in response is less than 10 -3 s.

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