Determination of oxalate by continuons analysis using photochemical oxidation by iron(III) and a CO2 electrode detector

1978 ◽  
Vol 56 (18) ◽  
pp. 2452-2458 ◽  
Author(s):  
Jean Margaret Cooley ◽  
Byron Kratochvil
Keyword(s):  
Carbon Dioxide ◽  
Calibration Curve ◽  
Theoretical Study ◽  
Ionic Species ◽  
Photochemical Oxidation ◽  
Optimum Conditions ◽  
Linear Calibration ◽  
Ion Concentrations ◽  
Co2 Electrode

Oxalate concentrations were measured by photochemical oxidation with iron(III) to carbon dioxide. Technicon AutoAnalyzer components were used to automate the sampling and mixing steps, and the carbon dioxide produced in the radiation step was measured with a CO2 electrode. Variables in the System were evaluated and the optimum conditions identified. A theoretical study was made of the effect on ionic species concentrations of variations in iron(III), acid, and counter ion concentrations. A linear calibration curve could be obtained for oxalate concentrations in the range of 2 × 10−4 to 0.02 M; by modifying conditions linearity could be achieved at both higher and lower concentration ranges. Several other acids are partially oxidized under optimum conditions for oxalate. Tartrate, citrate, and malonate introduce errors of 2% or less at concentrations equivalent to oxalate; malate and pyruvate cause errors on the order of 10%. Several small carboxylic acids were found to interfere with the CO2 electrode.

Separation and Determination of Some Aromatic Sulfones by Reversed-Phase High-Performance Liquid Chromatography

1994 ◽  
Vol 59 (3) ◽  
pp. 569-574 ◽  
Author(s):  
Josef Královský ◽  
Marta Kalhousová ◽  
Petr Šlosar
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
High Performance ◽  
Reversed Phase ◽  
Uv Spectra ◽  
Optimum Conditions ◽  
Linear Calibration ◽  
Technical Grade

The reversed-phase high-performance liquid chromatography of some selected, industrially important aromatic sulfones has been investigated. The chromatographic behaviour of three groups of aromatic sulfones has been studied. The optimum conditions of separation and UV spectra of the sulfones and some of their hydroxy and benzyloxy derivatives are presented. The dependences of capacity factors vs methanol content in mobile phase are mentioned. The results obtained have been applied to the quantitative analysis of different technical-grade samples and isomer mixtures. For all the separation methods mentioned the concentration ranges of linear calibration curves have been determined.

Rapid Determination of Sulfite by Flow Injection Analysis Based on Fuchsin′s Addition

2013 ◽  
Vol 295-298 ◽  
pp. 950-953 ◽  
Author(s):  
Dong Yuan ◽  
Da You Fu ◽  
Wen Yuan Tan
Keyword(s):  
Flow Injection ◽  
Addition Reaction ◽  
Rapid Determination ◽  
Sampling Rate ◽  
Optimum Conditions ◽  
Linear Calibration ◽  
Relative Standard ◽  
Replicate Measurements ◽  
Good Agreement

A rapid spectrophotometric method for flow injection determination of sulfite in tan wastewater is described. The proposed method was based on the addition reaction of sulfite with fuchsin in Na2B4O7-NaOH medium. The optimum conditions allow a linear calibration range of 0.01-1.20 μg ml-1 SO32-. The detection limit is 0.0023μg ml-1 (S/N=3), and the relative standard deviation for night replicate measurements is 1.1% for 0.5μg ml-1 of sulfite. The sampling rate is 60 samples h-1. The procedure has been applied to the determination of sulfite in tan wastewater. The results were in good agreement with those obtained by pararosaniline method.

CALIBRATED PLASMA PROCEDURE AND INR FOR PT STANDARDIZATION. DATA FROM THE FRENCH ETAL0N0RME QUALITY CONTROL SURVEYS

1987 ◽  
Author(s):  
A GOGUEL ◽  
A HOUBOUYAN ◽  
J ROUSSI
Keyword(s):  
Quality Control ◽  
Statistical Analysis ◽  
Calibration Curve ◽  
Large Scale ◽  
Linear Calibration ◽  
Efficient Procedure ◽  
Traditional Procedure ◽  
Common Scale

One of the aim of the survey conducted in last december 1986 was to assess the efficacy of 2 procedures of standardization :1) the INR system, derived from thromboplastin calibration and adopted in 1983 by the WHO.2) the Reference Calibrated Plasmas (RCP) procedure, evaluated on large scale, through French interlaboratory trials (1977-85), exhibiting net improvement of the dispersion of overall data.Labs were asked to perform with their local thromboplastin and method, the PT of a human lyophilized plasma 86 H/I, originated from long term antivitarnines-K (AVK) treated patients. Results were expressed *in time ; *in % activity, according to the traditional procedure based on saline dilutions of normal plasma ; *in INR using the ISI of the local reagent calibrated by the manufacturer. Calibrated plasmas procedure allow the determination of corrected activity ; *in % activity and INR, according to the linear calibration curve obtained from the PT of 2 reference calibrated plasmas with determinated activities in INR and % activity. These RCP were provided with and tested under the same conditions as plasma 86 H/I6 (2 systems of RCP : AVK and artificially depleted).Statistical analysis shows that the "RCP" procedure leads to the best improvement of the interlaboratory variation for the overall data, and the best uniformization of mean results, whatever the way of expression (%, INR), the thromboplastin brand, and the method of PT testing. Results play also in favour of a system of AVK reference plasmas, giving a better grouping than the artificial calibrated plasmas. The INR system nevertheless provides a common scale of data reporting, but might hold profit from an efficient procedure of standardization, such as the calibrated AVK plasmas procedure.Coefficient of variation (CV) expressed in %. Overall data PT of 86 H/I. French Etalonorme Survey.

scholarly journals Utility of N-Bromosuccinimide as a Green Chemical Reagent for Determination of H2-Receptor Antagonists in their Pharmaceutical Dosage Forms

2019 ◽  
Vol 27 (1) ◽  
pp. 47-64
Author(s):  
Ahmed I. Hassan
Keyword(s):  
Correlation Coefficients ◽  
Dosage Forms ◽  
Optimum Conditions ◽  
Linear Calibration ◽  
Receptor Antagonists ◽  
Pharmaceutical Dosage Forms ◽  
Drug Concentrations ◽  
Environmentally Safe ◽  
The Common

Abstract An environmentally safe, simple and robust spectrophotometric method has been developed for determination of H2-receptor antagonists namely: cimetidine (CIM), famotidine (FAM), nizatidine (NIZ), and ranitidine hydrochloride (RAN). The method was depend on the reaction of the studied drugs with N-bromosuccinimide (NBS), environmentally friendly reagent, and the excess NBS was measured by its reaction with phloroglucinol to give a yellow chromogenic product (λmax at 435 nm). The absorption intensity decrease (ΔA) was correlated with drug concentrations in the sample solutions. By using of the optimum conditions, linear calibration curves with good correlation coefficients (0.9958–0.9998) were found between the measured ΔA values and the corresponding drugs concentrations in the range of 12-80 μg mL−1. Limits of detection were in the range 1.31-2.21 μg mL−1. The proposed method was validated and successfully applied for the analysis of the above mentioned drugs in their bulk and pharmaceutical dosage forms with good recoveries (98.5 ± 0.98 to 102.5 ± 0.79%). No interferences were obtained from the common excipients. The proposed method was successfully applied for the analysis of H2RAs in their dosage forms and the results were comparable with that obtained by the official methods.

scholarly journals A Spectrophotometric Flow Injection Method for Determination of Ultratrace Amounts of Phenylhydrazine by Its Inhibition Effect on the Reaction of Thionin and Nitrite

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
M. Keyvanfard ◽  
Kh. Alizad
Keyword(s):  
Sulfuric Acid ◽  
Flow Injection ◽  
Sodium Nitrite ◽  
Calibration Graph ◽  
Optimum Conditions ◽  
Linear Calibration ◽  
Inhibition Effect ◽  
Colorimetric Procedure ◽  
Simple Flow

A simple flow injection colorimetric procedure for determining phenylhydrazine was established. It is based on the reaction of phenylhydrazine in sulfuric acid with thionin and sodium nitrite. Reaction was monitored spectrophotometrically by measuring thionin absorbance atλmax=602 nm. A standard or sample solution was injected into the sulfuric acid stream, which was then merged with sodium nitrite stream and thionin stream. Optimum conditions for determining phenylhydrazine were investigated by univariate method. Under the optimum conditions, a linear calibration graph was obtained over the range 0.05–0.60 μmol L−1, and the detection limit was 0.027 μmol L−1(s/n=3). The proposed method has been satisfactorily applied to the determination of phenylhydrazine in human serum and water samples.

scholarly journals A New Spectrophotometric Method for Analysis of Allopurinol in Aqueous Solutions and Pharmaceutical Preparations

2009 ◽  
Vol 6 (2) ◽  
pp. 309-314
Author(s):  
Baghdad Science Journal
Keyword(s):  
Absorption Spectrum ◽  
Aqueous Solutions ◽  
Spectrophotometric Method ◽  
Calibration Curve ◽  
Pharmaceutical Preparations ◽  
High Sensitivity ◽  
Good Stability ◽  
Optimum Conditions ◽  
Wide Range

A new method for determination of allopurinol in microgram level depending on its ability to reduce the yellow absorption spectrum of (I-3) at maximum wavelength ( ?max 350nm) . The optimum conditions such as "concentration of reactant materials , time of sitting and order of addition were studied to get a high sensitivity ( ? = 27229 l.mole-1.cm-1) sandal sensitivity : 0.0053 µg cm-2 ,with wide range of calibration curve ( 1 – 9 µg.ml-1 ) good stability (more then24 hr.) and repeatability ( RSD % : 2.1 -2.6 % ) , the Recovery % : ( 98.17 – 100.5 % ) , the Erel % ( 0.50 -1.83 % ) and the interference's of Xanthine , Cystein , Creatinine , Urea and the Glucose in 20 , 40 , 60 fold of analyate were also studied .

scholarly journals A Validated, Rapid HPLC-ESI-MS/MS Method for the Determination of Lycopsamine

2015 ◽  
Vol 10 (7) ◽  
pp. 1934578X1501000
Author(s):  
Nikoletta Jedlinszki ◽  
Dezső Csupor
Keyword(s):  
Quality Control ◽  
Calibration Curve ◽  
Pyrrolizidine Alkaloid ◽  
Validation Period ◽  
Aqueous Samples ◽  
Linear Calibration ◽  
Good Repeatability ◽  
Interday Precision ◽  
Control Samples

The aim of the present work was to develop and validate an HPLC-MS/MS method for the determination of a major pyrrolizidine alkaloid of comfrey (lycopsamine) in aqueous samples as a basis for the development of a method for the determination of absorption of lycopsamine by human skin. A linear calibration curve was established in the range of 1.32–440 ng. The intraday precision during the 3-day validation period ranged between 0.57 and 2.48% while the interday precision was 1.70% and 1.95% for quality control samples. LOD was 0.014 ng and recovery was above 97%. The lycopsamine content of the samples stored for 9 and 25 days at 22°C, 10°C and −25°C did not vary. These results underline the good repeatability and accuracy of our method and allow the analysis of samples with very low lycopsamine content.

scholarly journals Preconcentration and determination of Metformine Hydrochloride in different samples by cloud point extraction coupling with uv-visible spectrophotometry

2016 ◽  
Vol 13 (2) ◽  
pp. 470-479
Author(s):  
Baghdad Science Journal
Keyword(s):  
Cloud Point ◽  
Calibration Curve ◽  
Cloud Point Extraction ◽  
Limit Of Detection ◽  
Molar Absorptivity ◽  
Basic Medium ◽  
Optimum Conditions ◽  
Visible Spectrophotometry ◽  
Uv Visible

This work was influenced the separation and preconcentration steps were carried out to determination of metformin (MET) in pharmaceutical preparations and human serum samples. Complex formation method and cloud-point extraction (CPE) coupling with UV-Visible spectrophotometry were used to investigated of study target.The results has showed the best optical characteristic for calibration curve and statistical data which were obtained under optimum conditions. The first method is based on the reaction of MET with nickel (II) in alkaline medium an absorption maximum ?)max) at 434nm. ''Beer's low'' is obeyed in the concentration range (10-100µg.ml-1) with molar absorptivity of 3.9x103 L.mol-1.cm-1.The limit of detection and quantitation values were 2.37 and7.11 µg.ml-1 respectively. The second method based on extraction of traces amounts of MET using the cloud-point extraction (CPE). This method implicated for using of a nonionic surfactant (Triton x-114) as an extraction medium which was entrap the hydrophobic complex formed between MET and nickel(ii) in basic medium as reaction system for designing the CPE procedure. The optimum conditions were similar the first method expect the amount of surfactant which was 0.5 ml. The concentrations range of calibration curve from 3.5to100 µg.ml-1 and molar absorptivity of 1.2x104 L.mol-1.cm-1. In this method was access to less of concentrations in Limit of detection and quantitation which were 0.74and 2.22 µg.ml-1 respectively. The precise (RSD %) and accuracy (recovery %) of both methods were ranged between 0.24-0.47, 97.86-98.68 respectively. The data of two methods were appeared high acceptable with standered of British Pharmacopoeia through using statistic methods (f-test and t-test), that they may be used in analysis of MET.

Improved determination of D-glucaric acid in urine.

1981 ◽  
Vol 27 (3) ◽  
pp. 422-426 ◽  
Author(s):  
K Jung ◽  
D Scholz ◽  
G Schreiber
Keyword(s):  
Calibration Curve ◽  
Optimization Procedure ◽  
Optimization Criterion ◽  
Optimal Conditions ◽  
Glucaric Acid ◽  
Linear Calibration ◽  
Optimization Scheme ◽  
Urinary Creatinine ◽  
Glucuronidase Activity

Abstract Using a simplex optimization procedure, we have elaborated a sensitive and reliable micromethod for determining D-glucaric acid, based on inhibition of glucuronidase activity by 1,4-D-glucarolactone, produced from D-glucaric acid by heating. The maximum attainable difference between glucuronidase activity in the reaction mixture with and without D-glucaric acid was used as an optimization criterion. From the optimization scheme, 1 mmol/L 4-nitrophenyl-beta-D-glucuronide and pH 5.0 were found to be optimal conditions for determination of D-glucaric acid with this test. In contrast to other similar methods, in which a logarithmic calibration curve is used, we calculate D-glucaric acid with a linear calibration curve by using the Dixon (Biochem. J. 55: 170, 1953) plot. The coefficient of variation for the method (within-run and between-day precision) was from 3.1 to 5.8%. Men excrete more D-glucaric acid than do women per 24 hours, but we saw no sex-related differences in excretion of D-glucaric acid when it was expressed in terms of urinary creatinine.

Spectrophotometric determination of nickel(II) in different samples by complexation with some triazolylazo dyes

2006 ◽  
Vol 60 (2) ◽  
Author(s):  
A. Khedr
Keyword(s):  
Spectrophotometric Determination ◽  
Aqueous Media ◽  
Direct Determination ◽  
Optimum Conditions ◽  
Linear Calibration ◽  
Phenolic Ring ◽  
Determination Of Nickel ◽  
The Stability ◽  
Sensitive Spectrophotometric Method

AbstractA new sensitive spectrophotometric method for the determination of nickel(II) with 3-(2-hydroxy-5-acetyl-(L1),-5-ethoxycarbonyl-(L2),-5-methyl-(L3),-5-formyl-(L4),-5-bromophen-1-ylazo)-1,2,4-triazole (L5), and 3-(2,4-dihydroxyphen-1-ylazo)-1,2,4-triazole (L6) in aqueous media containing 40 vol. % methanol has been developed. The method is based on the formation of stable coloured Ni(II) complexes with stoichiometric ratios 1: 1 and 1: 2 (n(M): n(L)). Linear calibration graphs are obtained up to 7.04 µg cm−3 of nickel(II) under optimum conditions attained from investigation of complex formation. The absorption maxima varied from 485 nm to 545 nm and the molar absorptivities ranged from 0.84 × 104 to 4.65 × 104 dm3 mol−1 cm−1 for 1: 1 and 1: 2 (n(M): n(L)) complexes with varying the substituent on the phenolic ring. The optimum ranges for the direct determination of nickel(II) (Ringbom) and the stability constants of the formed complexes are determined. The developed method was applied to the spectrophotometric determination of nickel(II) in some samples with satisfactory results.

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