Kinetic study of the Jaffé reaction for quantifying creatinine in serum: 2. Evaluation of buffered reagent and comparison of different data-processing options.

1989 ◽  
Vol 35 (3) ◽  
pp. 360-363 ◽  
Author(s):  
B L Bacon ◽  
H L Pardue
Keyword(s):  
Data Processing ◽  
Curve Fitting ◽  
Fixed Time ◽  
Good Precision ◽  
Creatinine Concentration ◽  
Kinetic Determination ◽  
Predictive Method ◽  
Target Values ◽  
Standard Additions

Abstract Here we describe the evaluation of several data-processing options for the kinetic determination of creatinine by use of the Jaffé reaction. Data-processing options evaluated include initial-rate, two-point fixed-time, rate at t = k-1, and multipoint curve-fitting predictive methods. We evaluated these options for a buffered formulation of the Jaffé reagent and studied the effects of potential interferents, including glucose, acetoacetate, bilirubin, and albumin, on each option. To reduce effects of bilirubin, we evaluated the inclusion of a preoxidation step with ferricyanide. All the data-processing options gave good precision and linearity between the measurement objective and creatinine concentration. However, differences between slopes of calibration plots in aqueous and serum matrices ranged from a high of +60% for the two-point, fixed-time method to a low of -11% for the curve-fitting, predictive method. Standard additions of creatinine to sera were quantified reliably (yielding 96% to 102% of target values) by the predictive method and less reliably (62% to 102%) by the other methods. We conclude that the predictive method has the potential to yield the most reliable results for creatinine.

scholarly journals A Simple and Sensitive Inhibitory Kinetic Method for the Carbocisteine Determination

2021 ◽  
Vol 66 (1) ◽  
Author(s):  
Abhishek Srivastava ◽  
Vivek Sharma ◽  
Vinay Kumar Singh ◽  
Krishna Srivastava
Keyword(s):  
Good Accuracy ◽  
Quantitative Estimation ◽  
Kinetic Method ◽  
Fixed Time ◽  
Disodium Salt ◽  
Disulfonic Acid ◽  
Stable Complex ◽  
Reaction Conditions ◽  
Kinetic Determination

Abstract. A fast, reproducible, and sensitive method is proposed for the kinetic determination of carbocisteine (CCys). The method depends on the inhibitory property of carbocisteine, which reduces the Hg2+ catalyzed substitution rate of cyanide from [Ru(CN)6]4- with N-R-salt (1-Nitroso-2-naphthol-3,6-disulfonic acid disodium salt) via forming a stable complex with Hg2+. Spectrophotometric measurements were carried out by recording the absorbance at 525 nm (λmax of [Ru(CN)5 Nitroso-R-Salt]3- complex) at a fixed time of 10 and 15 min under the optimized reaction conditions with [N-R-salt] = 4.5 × 10-4 M, I = 0.05 M (KNO3), Temp = 45.0 ± 0.2 o C, pH = 7.0 ± 0.03, [Hg2+] = 8.0 × 10-5 M and [Ru(CN)64-] = 4.25 × 10-5  M. With the proposed method, CCys can be determined quantitatively down to 3.0 × 10-6 M. This methodology can be effectively used for the rapid quantitative estimation of CCys in the pharmaceutical samples with good accuracy and reproducibility. The addition of common excipients in pharmaceuticals even up to 1000 times with [CCys] does not interfere significantly in the estimation of CCys.   Resumen. Se propone un método rápido, reproducibley sensible para la determinación cinética de la carbocisteina (CCys). El método depende de la propiedad inhibitoria de la carbocisteina que reduce la tasa de sustitución catalizada por Hg2+ del cianuro de [Ru(CN)6]4- con la sal N-R (sal disódica del ácido 1-Nitroso-2-naftol-3,6-disulfónico) mediante la formación de un complejo estable con Hg2+. Las mediciones espectrofotométricas se llevaron a cabo registrando la absorbancia a 525 nm (λmax del complejo [Ru(CN)5 Sal-Nitroso-R]3-) en un tiempo fijo de 10 y 15 min en las condiciones de reacción optimizadas con [sal-NR] = 4.5 × 10-4 M, I = 0.05 M (KNO3), Temp = 45.0 ± 0.2 o C, pH = 7.0 ± 0.03, [Hg2+] = 8.0 × 10-5 M y [Ru(CN)64-] = 4.25 × 10-5 M. Con el método propuesto, CCys se puede determinar cuantitativamente hasta 3,0 × 10-6 M. Esta metodología se puede utilizar eficazmente para la estimación cuantitativa rápida de CCys en las muestras farmacéuticas con buena precisión y reproducibilidad. La adición de excipientes comunes en productos farmacéuticos incluso hasta 1000 veces con [CCys] no interfiere significativamente en la estimación de CCys.

A stopped-flow clinical analyzer in which immobilized-enzyme reaction loops are used.

1977 ◽  
Vol 23 (6) ◽  
pp. 1033-1036 ◽  
Author(s):  
M D Joseph ◽  
D J Kasprzak ◽  
S R Crouch
Keyword(s):  
Immobilized Enzyme ◽  
Enzymatic Reaction ◽  
Enzyme Reaction ◽  
Fixed Time ◽  
Stopped Flow ◽  
Good Precision ◽  
Indicator Reaction ◽  
Flow Mixing ◽  
Kinetic Mode

Abstract A stopped-flow clinical analyzer is described that makes use of a reaction loop containing immobilized enzyme(s) for the determination of the analyte/substrate. The analyzer has been evaluated by determining glucose with immobilized glucose oxidase. The stopped-flow mixing system was constructed at a current cost of less than $500. The analyzer separates the enzymatic reaction from a followup, spectrophotometric indicator reaction. This separation allows the enzymatic reaction to be used in either a fixed-time, kinetic mode or in an equilibrium mode. Likewise, the indicator reaction can be used in either mode. Results for glucose in blood serum indicate that good precision and accuracy can be obtained.

An enzymic, reaction-rate assay for serum creatinine with a centrifugal analyzer.

1982 ◽  
Vol 28 (1) ◽  
pp. 114-117 ◽  
Author(s):  
P K Jaynes ◽  
R D Feld ◽  
G F Johnson
Keyword(s):  
Reaction Rate ◽  
Dynamic Range ◽  
Ketone Bodies ◽  
Creatinine Concentration ◽  
Kinetic Determination ◽  
Micro Scale ◽  
Standard Curve ◽  
Esterified Fatty Acids ◽  
Absorbance Change

Abstract We describe a procedure for specific, rapid, kinetic determination of creatinine, in which a manual coupled-enzyme micro-scale assay is adapted to a centrifugal analyzer. The creatinine reaction is ultimately linked to NADH utilization, which is measured by the absorbance change at 340 nm. This procedure requires 15 microL of serum and the standard curve is linear to a creatinine concentration of 200 mg/L. A four-point kinetic algorithm allows the dynamic range of the assay to be extended without sacrificing sensitivity, and makes a separate serum blank unnecessary. The within-run precision (CV) for samples with a creatinine concentration of 11 and 52 mg/L was 5.6 and 2.4%, respectively; day-to-day CV for a creatinine concentration of 11 mg/L was 7.7% (n = 21). We compared this procedure with a kinetic Jaffé procedure, with excellent agreement (r = 0.996; y = 0.96x + 2.4 mg/L). Bilirubin, non-esterified fatty acids, and ketone bodies do not affect creatinine determinations by this method; thus the method is especially useful for monitoring the renal function of diabetics.

Determination of Verapamil in Exhaled Breath Condensate by Using Microextraction and Liquid Chromatography

2019 ◽  
Vol 15 (5) ◽  
pp. 535-541 ◽  
Author(s):  
Fariba Pourkarim ◽  
Ali Shayanfar ◽  
Maryam Khoubnasabjafari ◽  
Fariborz Akbarzadeh ◽  
Sanaz Sajedi-Amin ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Exhaled Breath Condensate ◽  
Exhaled Breath ◽  
Good Precision ◽  
Dispersive Liquid Liquid Microextraction ◽  
Breath Condensate ◽  
Liquid Microextraction

Background:Developing a simple analysis method for quantification of drug concentration is one of the essential issues in pharmacokinetic and therapeutic drug monitoring studies.Objective:A fast and reliable dispersive liquid-liquid microextraction procedure was employed for preconcentration of verapamil in exhaled breath condensate (EBC) samples and this was followed by the determination with high-performance liquid chromatography-ultraviolet detection.Methods:A reverse-phase high-performance liquid chromatography (RP-HPLC) combined with a dispersive liquid-liquid microextraction method (DLLME) was applied for quantification of verapamil in the EBC samples. The developed method was validated according to FDA guidelines.Results:Under the optimum conditions, the method provided a linear range between 0.07 and 0.8 µg.mL-1 with a coefficient of determination of 0.998. The intra- and inter-day relative standard deviation and relative error values of the method were below 15%, which indicated good precision and accuracy. The proposed method was successfully applied for the analysis of verapamil in two real samples with concentrations of 0.07 and 0.09 µg.mL-1.Conclusion:The established HPLC-UV-DLLME method could be applied for the analysis of verapamil in human EBC samples.

Determination of Epsilon Aminocaproic Acid Based on Charge Transfer Complexation with p-Nitrophenlol by Spectrophotometry

2020 ◽  
Vol 16 ◽  
Author(s):  
Sheng-Yun Li ◽  
Fang Tian
Keyword(s):  
Charge Transfer ◽  
Aminocaproic Acid ◽  
Concentration Limit ◽  
Official Method ◽  
Good Precision ◽  
Pharmaceutical Dosage Forms ◽  
Relative Standard ◽  
A Charge ◽  
Epsilon Aminocaproic Acid

: A spectrophotometry was investigated for the determination of epsilon aminocaproic acid (EACA) with p-nitrophenol (PNP). The method was based on a charge transfer (CT) complexation of this drug as n-electron donor with π-acceptor PNP. Experiment indicated that the CT complexation was carried out at room temperature for 10 minutes in dimethyl sulfoxide solvent. The spectrum obtained for EACA/PNP system showed the maximum absorption band at wavelength of 425 nm. The stoichiometry of the CT complex was found to be 1:1 ratio by Job’s method between the donor and the acceptor. Different variables affecting the complexation were carefully studied and optimized. At the optimum reaction conditions, Beer’s law was obeyed in a concentration limit of 1～6 µg mL-1. The relative standard deviation was less than 2.9%. The apparent molar absoptivity was determined to be 1.86×104 L mol-1cm-1 at 425 nm. The CT complexation was also confirmed by both FTIR and 1H NMR measurements. The thermodynamic properties and reaction mechanism of the CT complexation have been discussed. The developed method could be applied successfully for the determination of the studied compound in its pharmaceutical dosage forms with a good precision and accuracy compared to official method as revealed by t- and F-tests.

Deproteinizing methods evaluated for determination of uric acid in serum by reversed-phase liquid chromatography with ultraviolet detection.

1987 ◽  
Vol 33 (8) ◽  
pp. 1427-1430 ◽  
Author(s):  
R Sakuma ◽  
T Nishina ◽  
M Kitamura
Keyword(s):  
Uric Acid ◽  
Liquid Chromatography ◽  
Perchloric Acid ◽  
High Performance ◽  
Reversed Phase ◽  
Precipitation Method ◽  
Zinc Hydroxide ◽  
Good Precision ◽  
Ultraviolet Detection

Abstract We evaluated six deproteinizing methods for determination of uric acid in serum by "high-performance" liquid chromatography with ultraviolet detection: those involving zinc hydroxide, sodium tungstate, trichloroacetic acid, perchloric acid, acetonitrile, and centrifugal ultrafiltration (with Amicon MPS-1 devices). We used a Toyosoda ODS-120A reversed-phase column. The mobile phase was sodium phosphate buffer (40 mmol/L, pH 2.2) containing 20 mL of methanol per liter. Absorbance of the eluate was monitored at 284 nm. The precipitation method with perchloric acid gave high recoveries of uric acid and good precision, and results agreed with those by the uricase-catalase method of Kageyama (Clin Chim Acta 1971;31:421-6).

scholarly journals Determination of the order of fractional derivative for subdiffusion equations

2020 ◽  
Vol 23 (6) ◽  
pp. 1647-1662
Author(s):  
Ravshan Ashurov ◽  
Sabir Umarov
Keyword(s):  
Fractional Derivative ◽  
Fixed Time ◽  
Time Instant ◽  
Observation Data ◽  
Additional Information ◽  
Fractional Modeling ◽  
Time Fractional Derivative ◽  
The Right ◽  
Right Order

Abstract The identification of the right order of the equation in applied fractional modeling plays an important role. In this paper we consider an inverse problem for determining the order of time fractional derivative in a subdiffusion equation with an arbitrary second order elliptic differential operator. We prove that the additional information about the solution at a fixed time instant at a monitoring location, as “the observation data”, identifies uniquely the order of the fractional derivative.

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