Spectrophotometric determination of sulfanilic acid and sulfonamides in pharmaceutical samples with potassium 1,2-naphthoquinone-4-sulfonate

An accurate and simple method is proposed for the determination of sulfanilic acid in the presence of sulfonamides. This method is based on measuring the intensity of the red colour that develops when sulfanilic acid is allowed to react with potassium 1,2-naphthoquinone-4-sulphonate (NS) in a chloroaceticchloroacetate buffer at pH 3,4. Colour development reaches completion after 2 h, allowing sulfanilic acid to be quantified spectrophotometrically at 470 nm (ε = 4.7 × 103 L mol−1 cm−1). The main product causing colour formation, potassium 1,2-naphthoquinone-4-(N-aminophenylen-4-sulphonate) (NSSA), was isolated and characterized. When samples also contain sulfonamides an extraction into chloroform must be performed. Sulfanilic acid in binary mixtures with sulfanilamide, sulfacetamide, or sulfathiazole can be determined either by direct measurement of the aqueous phase after extraction at 470 nm or by subtracting from the absorbance of the aqueous phase before extraction the absorbance of sulfonamide as determined by measuring the extracted chloroform phase at 345 nm. Sulfadiazine, sulfamethoxipyridazine, and sulfamethoxazole interferences are prevented by their extraction into chloroform at pH 7.2; these species cannot be determined. The effects of pH, reagent concentration, time, and temperature on colour formation were investigated. In all cases the standard addition method gave more accurate results. The method was applied to several pharmaceutical samples. Keywords: spectrophotometry, sulfanilic acid, sulfonamides, potassium 1,2-napthoquinone-4-sulphonate.

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Determination of unconjugated 3-methoxy-4-hydroxyphenylglycol by liquid chromatography for monitoring inhibition of monoamine oxidase activity in plasma.

Clinical Chemistry ◽

10.1093/clinchem/33.11.2078 ◽

1987 ◽

Vol 33 (11) ◽

pp. 2078-2080 ◽

Cited By ~ 8

Author(s):

R N Gupta ◽

M Steiner ◽

M Lew

Keyword(s):

Liquid Chromatography ◽

Monoamine Oxidase ◽

Ethyl Acetate ◽

Aqueous Phase ◽

Oxidase Activity ◽

Back Extraction ◽

Monoamine Oxidase Activity ◽

Simple Method ◽

Extraction Recovery

Abstract We describe a simple method for extracting 3-methoxy-4-hydroxyphenylglycol (MHPG) from plasma. The sample is applied to a 1-mL "Extrelut" column (EM Industries) and eluted 15 min later with ethyl acetate. After mixing the eluate with pentane and back-extraction into water, we inject 25 or 50 microL of the aqueous phase onto a Beckman 15 cm x 4.6 mm (i.d.) column packed with 5-micron ODS particles (Beckman). Peaks are detected with a coulometric detector. The resulting chromatogram is clean, with few extraneous peaks. The extraction recovery of MHPG is 55-60%, which allows for detection of as little as 0.2 microgram of the analyte per liter. The decrease in the concentration of MHPG in plasma of patients treated with phenelzine agrees with the decrease in monoamine oxidase activity in platelets of these patients.

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Voltammetric Determination of Phenylalanine Using Chemically Modified Screen-Printed Based Sensors

Chemosensors ◽

10.3390/chemosensors8040113 ◽

2020 ◽

Vol 8 (4) ◽

pp. 113

Author(s):

Ancuta Dinu ◽

Constantin Apetrei

Keyword(s):

Prussian Blue ◽

Direct Determination ◽

Standard Addition ◽

Pharmaceutical Products ◽

Electrochemical Process ◽

Pharmaceutical Samples ◽

Analytical Recovery ◽

Relative Standard ◽

Screen Printed

This paper describes the sensitive properties of screen-printed carbon electrodes (SPCE) modified by using three different electroactive chemical compounds: Meldola’s Blue, Cobalt Phthalocyanine and Prussian Blue, respectively. It was demonstrated that the Prussian Blue (PB) modified SPCE presented electrochemical signals with the highest performances in terms of electrochemical process kinetics and sensitivity in all the solutions analyzed. PB-SPCE was demonstrated to detect Phe through the influence it exerts on the redox processes of PB. The PB-SPCE calibration have shown a linearity range of 0.33–14.5 µM, a detection limit (LOD) of 1.23 × 10−8 M and the standard deviation relative to 3%. The PB-SPCE sensor was used to determine Phe by means of calibration and standard addition techniques on pure samples, on simple pharmaceutical samples or on multicomponent pharmaceutical samples. Direct determination of the concentration of 4 × 10−6–5 × 10−5 M Phe in KCl solution showed that the analytical recovery falls in the range of 99.75–100.28%, and relative standard deviations in the range of 2.28–3.02%. The sensors were successfully applied to determine the Phe in pharmaceuticals. The validation of the method was performed by using the FTIR, and by comparing the results obtained by PB-SPCE in the analysis of three pharmaceutical products of different concentrations with those indicated by the producer.

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A simple method for the determination of 5-vinyloxazolidine-2-thione in rapeseed meal

Canadian Journal of Biochemistry ◽

10.1139/o69-125 ◽

1969 ◽

Vol 47 (8) ◽

pp. 817-818 ◽

Cited By ~ 3

Author(s):

A. Szewczuk ◽

P. Mastalerz ◽

W. Nadwyczawski

Keyword(s):

Organic Solvents ◽

Aqueous Phase ◽

Rapeseed Meal ◽

New Method ◽

Simple Method ◽

Titrimetric Method ◽

Azide Ion ◽

The Family ◽

Titrimetric Determination

5-Vinyloxazolidine-2-thione (VOT), a goitrogenic substance occurring in plants of the family Cruciferae, was found to catalyze the reduction of iodine by azide ion, the consumption of iodine being proportional to the amount of VOT. Based on these observations, a sensitive, titrimetric method of VOT determination was developed. The new method obviates the necessity of VOT extraction from the aqueous phase with organic solvents. Sensitivity and accuracy of titrimetric determination of VOT are comparable with those of spectrophotometric procedures.

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Quantitative Determination of Arsenate in Dried Shrimp by Spectrophotometric Measurement of its Heteropoly Blue

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.705.9 ◽

2013 ◽

Vol 705 ◽

pp. 9-14

Author(s):

Charuwan Suitcharit

Keyword(s):

Complex Formation ◽

Standard Addition ◽

Cost Effective ◽

Calibration Graph ◽

Formation Condition ◽

Blue Color ◽

Molybdenum Blue ◽

Effects Of Ph ◽

Good Agreement

A cost-effective and sensitive spectrophotometric method for the determination of arsenate in dried shrimp has been developed using molybdenum blue as a chromogenic reagent. The method is based on arsenate conversion to arsenomolybdate heteropoly blue having an absorbance maximum at 870 nm. The effects of pH, time, temperature and light on its complex formation were investigated. The optimal complex formation condition at pH 4 in 90 min at 15+1°C was obtained and the blue color was favorable developed in daylight. The proposed method has been successfully applied for the determination of arsenate in samples with the addition of DTPA to eliminate the interferences resulting in increased selectivity. The standard addition calibration graph was constructed with the linear range extended to 40 μgL-1 (r2 = 0.9987). The detection limit (S/N = 3) of 3.21 μgL-1, and the precision of 3.13% (RSD) were obtained. The method has good recovery of 95% for the determination of arsenate. The amounts of arsenate in dried shrimp samples compared with those obtained from ICP-OES were shown to be in good agreement (r = 0.998).

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Analytical Methodology for Trace Determination of Propoxur and Fenitrothion Pesticide Residues by Decanoic Acid Modified Magnetic Nanoparticles

Molecules ◽

10.3390/molecules24244621 ◽

2019 ◽

Vol 24 (24) ◽

pp. 4621 ◽

Cited By ~ 2

Author(s):

Amine Gizem Canlı ◽

Bilge Sürücü ◽

Halil İbrahim Ulusoy ◽

Erkan Yılmaz ◽

Abuzar Kabir ◽

...

Keyword(s):

Water Samples ◽

Magnetic Particles ◽

Solid Phase ◽

Standard Addition ◽

Decanoic Acid ◽

Environmental Water ◽

Environmental Water Samples ◽

Analytical Methodology ◽

Simple Method

A sensitive, rapid, reliable, and easily applicable method based on magnetic solid phase extraction (MSPE) combined with HPLC-PDA was developed for monitoring propoxur (PRO) and fenitrothion (FEN) pesticides in environmental water samples. The effect of major experimental variables on the extraction efficiency of both the pesticides was investigated and optimized systematically. For this purpose, a new magnetic material containing decanoic acid on the surface of particles was synthesized and characterized by XRD, FT-IR, SEM, EDX, and TGA analysis in detail. The simultaneous determination of pesticide molecules was carried out by using a Luna Omega C18 column, isocratic elution of acetonitrile (ACN): Water (70:30 v/v) with a flow rate of 1.2 mL min−1. After MSPE, the linear range for pesticide molecules (r2 > 0.9982) was obtained in the range of 5–800 and 10–800 ng mL−1, respectively. The limit of detections (LOD) are 1.43 and 4.71 ng mL−1 for PRO and FEN, respectively while RSDs % are below 3.5%. The applicability of the proposed method in four different environmental samples were also investigated using a standard addition-recovery procedure. Average recoveries at two spiking levels were over the range of 91.3–102.5% with RSD < 5.0% (n = 3). The obtained results show that decanoic acid grafted magnetic particles in MSPE combined with HPLC-PDA is a fast and simple method for the determination of PRO and FEN in environmental water samples.

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Simultaneous Determination of Low Parts-per-Billion Level Pb and as in Waters Using Energy-Dispersive X-Ray Fluorescence Spectrometry

Applied Spectroscopy ◽

10.1366/0003702011951920 ◽

2001 ◽

Vol 55 (3) ◽

pp. 298-306 ◽

Cited By ~ 9

Author(s):

Terrance D. Hettipathirana ◽

Lester H. Smith ◽

Keith Norrish

Keyword(s):

Simultaneous Determination ◽

Matrix Effects ◽

Certified Reference Materials ◽

Ferric Hydroxide ◽

Standard Addition ◽

Energy Dispersive ◽

Fluorescence Spectrometry ◽

Simple Method ◽

X Ray

A simple method is described for the simultaneous determination of low parts-per-billion levels of As and Pb in waters. The method is based on the preconcentration of analytes by adsorbing them onto hydrous ferric hydroxide (HFO) impregnated into the 13 mm diameter area at the center of 32 mm diameter circular disks cut from Whatman filter papers. The adsorbed analytes are determined by using thin-layer energy-dispersive X-ray fluorescence spectrometry. The X-ray intensity of As and Pb adsorbed onto HFO is linearly proportional to the concentration up to 80 μg/L. The precision of the method is ∼ 0.5–5%, and the method detection limit for Pb and As in seawater is 0.63 and 0.21 μg/L, respectively. The method was validated by analyzing the certified reference materials SLRS-3 (riverine water), CASS-4 (nearshore seawater), and NASS-5 (offshore seawater) for As. The adsorption characteristics of Pb, As(III), As(V), Se(IV), Se(VI), and Hg onto the HFO impregnated disks, the interspecies adsorption effects, and the use of the standard addition method to compensate for matrix effects are also presented.

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CFIA-Turbidimetric and Photometric Determination of Vitamin B9 (Folic acid) Using LEDs as a Source of Irradiation and Two Solar Cells as an Energy Transducer

Baghdad Science Journal ◽

10.21123/bsj.14.4.773-786 ◽

2017 ◽

Vol 14 (4) ◽

pp. 773-786

Author(s):

Baghdad Science Journal

Keyword(s):

Folic Acid ◽

Classical Method ◽

Standard Addition ◽

Photometric Determination ◽

Calibration Graph ◽

Ammonium Molybdate ◽

Simple Method ◽

Vitamin B9 ◽

Significant Difference

A specific, sensitive and simple method was used for the determination of: vitamin B9 (Folic acid) in pure and pharmaceutical formulations using continuous flow injection analysis. The method is based on formation of ion pair compound between folic acid and ammonium molybdate in an aqueous medium to obtain a gray precipitate complex, using homemade; Ayah-6SX1-ST-2D solar cell CFI Analyzer. Optimum parameters was studied to increase the sensitivity for developed method. The linear range for the calibration graph was 0.01-0.6 mMol.L-1 of vitamin B9 and LOD was 131.994 ng/sample with correlation coefficient ( r ) of 0.9810, RSD% was lower than 0.1%, (n=9) for the determination of vitamin B9 at concentration (0.07and 0.5) mMol.L-1 respectively. The developed method was applied successfully for the determination of vitamin B9 in pharmaceutical tablets. A comparison was made between two methods: developed method and the classical UV spectrophotometric method at ?max=255 nm, by using the standard addition method via the use of paired t-test. It showed that there was no significant difference between the developed method and the classical method for determination vitamin B9 at 95% confidence level.

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Simplified determination of urinary delta-aminolevulinic acid in a wide range of concentrations.

Clinical Chemistry ◽

10.1093/clinchem/25.4.581 ◽

1979 ◽

Vol 25 (4) ◽

pp. 581-583

Author(s):

H D Fiorentina ◽

M Grogna ◽

F Dewiest

Keyword(s):

Chromatographic Method ◽

Analytical Procedure ◽

Aminolevulinic Acid ◽

Internal Standard ◽

Standard Addition ◽

Simple Method ◽

Wide Range ◽

Arch Environ Health

Abstract We describe a simple method for measuring delta-aminole-vulinic acid in urine without the need for the seldom-used but time-consuming internal-standard addition step. It combines the analytical procedure described by Tomokuni and Ogata [Clin. Chem. 18, 1534 (1972)] and a correction based on urine density to obtain, more rapidly and less expensively, results as accurate as those given by the Davis and Andelman [Arch. Environ. Health 15, 53 (1967)] chromatographic method.

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Colorimetric and Spectrophotometric Determination of Total and Non-phenolic Alkaloids in Ipeca and Its Formulations

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/62.5.1113 ◽

1979 ◽

Vol 62 (5) ◽

pp. 1113-1115

Author(s):

Mohamed R I Saleh ◽

Sawsan El-Masry ◽

Nagwa El-Shaer

Keyword(s):

Standard Deviation ◽

Small Sample ◽

Acid Extract ◽

Simple Method ◽

British Pharmacopoeia ◽

Total Alkaloids ◽

Present Procedure ◽

Relative Standard ◽

Chloroform Phase

Abstract A simple method, requiring no chromatographic separation, is presented for the determination of the total and non-phenolic alkaloids in ipeca and its preparations. The complex formed between the alkaloid and methyl orange at pH 5.0 is extracted with chloroform and treated with 0.1N NaOH. The liberated dye, determined at 460 nm, is a measure of the total alkaloids. The chloroform phase remaining is treated with 0.1N H2SO4, and the acid extract is measured at 283 nm for the non-phenolic alkaloids, calculated as emetine. The proposed method was successfully applied to samples of ipeca powder, ipeca tincture, and 3 British Pharmaceutical Codex mixtures containing ipeca tincture, namely, ipecacuanha mixture, pediatric; ipecacuanha and ammonia mixture, pediatric; and belladonna and ipecacuanha mixture, pediatric. The proposed method compares favorably with the Egyptian Pharmacopoeia, British Pharmacopoeia, and USP methods and has a relative standard deviation of 1.54%. The present procedure is less time-consuming and requires about 45 and 90 min for the assay of ipeca tincture and powder, respectively. Only a small sample (0.2 mL tincture or 1.0 g powder) is required.

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