scholarly journals Theoretical description of the ligand function for ionoselective electrodes reversible to metal anion complexes. 1. Lower detection limit and its determining factors

2020 ◽  
pp. 17-28
Author(s):  
Vladimir V. Egorov ◽  
Andrei V. Semenov ◽  
Andrei D. Novakovskii ◽  
Yauhen B. Akayeu
Keyword(s):  
Detection Limit ◽  
Layer Thickness ◽  
Diffusion Layer ◽  
Theoretical Description ◽  
Diffusion Layer Thickness ◽  
Thiocyanate Ion ◽  
Lower Detection Limit ◽  
Diffusion Parameters ◽  
Lower Detection ◽  
And Diffusion

Within the framework of the steady-state diffusion model, the theoretical description for the thiocyanate ion lower detection limit (LDL) by the tetrathiocyanatozincate selective electrode, has been presented. The main assumptions of this model are constancy of the ion exchanger concentration along the membrane, traditionally used in various phaseboundary potential diffusion models, and linear profiles of components’ concentrations in diffusion layers. Simple quantitative expressions have been obtained, connecting thiocyanate ion concentration in the solution surface layer (responsible for LDL value) with phase boundary extraction equilibria constants, stability constants for zinc thiocyanate complexes, and diffusion parameters in the membrane and solution phases. Calculated LDL values are in good agreement with experimental data provided in the literature. It has been shown that LDL can be reduced substantially by controlling such easily regulated diffusion parameters as diffusion layer thickness in the membrane phase, which is a function of time, and diffusion layer thickness of the sample solution, which is governed by stirring regime.

Exchange Current Density and Diffusion Layer Thickness in Molten LiCl-KCl Eutectic: A Modeling Perspective for Pyroprocessing of Metal Fuels

2016 ◽  
Vol 195 (3) ◽  
pp. 253-272 ◽  
Author(s):  
Suddhasattwa Ghosh ◽  
Krishan Kumar ◽  
Aligati Venkatesh ◽  
P. Venkatesh ◽  
Bandi Prabhakara Reddy
Keyword(s):  
Layer Thickness ◽  
Diffusion Layer ◽  
Current Density ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Diffusion Layer Thickness ◽  
And Diffusion

A novel 3D Zn-coordination polymer based on a multiresponsive fluorescent sensor demonstrating outstanding sensitivities and selectivities for the efficient detection of multiple analytes

2021 ◽  
Author(s):  
Yu Liu ◽  
Yan Wang ◽  
Xiao-Sa Zhang ◽  
Yu-Shu Sheng ◽  
Wen-Ze Li ◽  
...  
Keyword(s):  
Detection Limit ◽  
Coordination Polymer ◽  
Fluorescent Sensor ◽  
Lower Detection Limit ◽  
Ph Values ◽  
Efficient Detection ◽  
Wide Range ◽  
Lower Detection ◽  
Multiple Analytes

A Zn-CP exhibits remarkable fluorescence behaviours and stability in a wide range of pH values. It can become an outstanding candidate in the selective sensing of Fe3+, Mg2+, Cr2O72−, MnO4−, NB and NM at a lower detection limit.

Manual Immunonephelometric Assay of Proteins, with Use of Polymer Enhancement

1974 ◽  
Vol 20 (9) ◽  
pp. 1181-1186 ◽  
Author(s):  
Jorge Lizana ◽  
Kristoffer Hellsing
Keyword(s):  
Detection Limit ◽  
Urinary Albumin ◽  
Optimal Time ◽  
Immunological Reaction ◽  
Reaction Conditions ◽  
Enhancing Effect ◽  
Lower Detection Limit ◽  
Small Series ◽  
Lower Detection ◽  
Immunonephelometric Assay

Abstract A manual immunonephelometric method for proteins has been developed by using an ordinary fluorometer as a nephelometer. By applying the enhancing effect of polyethylene glycol (av mol wt, 6000) on the immunological reaction, albumin and fibrinogen were quantitated after a 10-min reaction time. Under the present conditions the sensitivity was increased and thus antiserum consumption was decreased. The reaction conditions were carefully studied with respect to optimal time and concentration of the reactants. The precision of the method was 2.6-3.6% (CV). The lower detection limit in the albumin-antialbumin system was 0.1 mg/liter. Comparative studies showed a correlation coefficient of 0.991 with an automated immunonephelometric method for urinary albumin, and of 0.908 with a thrombin clottable method for plasma fibrinogen. We especially suggest use of this manual immunonephelometric method where small series of samples are to be analyzed.

New noncompetitive immunoassays of small analytes

1995 ◽  
Vol 41 (7) ◽  
pp. 986-990 ◽  
Author(s):  
U Piran ◽  
W J Riordan ◽  
L A Livshin
Keyword(s):  
Detection Limit ◽  
Liquid Phase ◽  
Binding Sites ◽  
Dynamic Range ◽  
Lower Detection Limit ◽  
Controlled Pore Glass ◽  
Lower Detection ◽  
Pore Glass ◽  
Clinically Significant ◽  
Acridinium Ester

Abstract We developed a novel noncompetitive immunoassay format for monoepitopic analytes and describe here a model assay for triiodothyronine (T3), performed on Ciba Corning's ACS:180 analyzer. Acridinium ester (AE)-labeled bivalent anti-T3 was incubated with the sample, producing AE-anti-T3/T3 complexes and unreacted AE-anti-T3. Controlled-pore glass particles (CPG) with immobilized diiodothyronine (T2) were then added in excess, to bind AE-anti-T3 possessing two unoccupied binding sites but not AE-anti-T3 bound to one or two T3 molecules. Paramagnetic particles (PMP) with immobilized anti-AE were then added to the same cuvette to capture AE-anti-T3/T3 complexes; AE-anti-T3 bound to the surface of CPG, however, was not captured, because of steric hindrance. After the incubation, the PMP was magnetically separated to remove the liquid phase and the suspended CPG from the cuvette. The chemiluminescence associate with the PMP remaining in the cuvette was then measured. This noncompetitive T3 assay exhibited a 10-fold lower detection limit than the equivalent competitive T3 assay, i.e., 0.3 vs pg/test. Imprecision (CV) in the clinically significant range was 6% or less. The assay also displayed two- to sevenfold lower cross-reactivities and a wider dynamic range.

Highly Sensitive Paper-Disc Assays for Detecting Penicillin in Milk

1985 ◽  
Vol 48 (1) ◽  
pp. 16-20 ◽  
Author(s):  
GINA M. BALBI ◽  
PAUL A. HARTMAN
Keyword(s):  
Detection Limit ◽  
Starter Cultures ◽  
Biologically Active ◽  
Penicillin G ◽  
Lower Detection Limit ◽  
Critical Concentrations ◽  
Plate Assay ◽  
Lower Detection ◽  
Standard Assay ◽  
Dairy Starter Cultures

A modified Bacillus subtilis disc-plate assay could detect 0.015 I.U. of penicillin G per ml of milk, whereas the lower detection limit of the standard assay was 0.050 I.U. per ml. Likewise, a modified Bacillus stearothermophilus disc-plate assay could detect 0.003 I.U. of penicillin G per ml of milk, whereas the lower detection limit of the standard assay was 0.005 I.U. per ml. Increased sensitivities were accomplished by preloading assay discs with “critical” concentrations so that minute quantities of antibiotic above the “critical” concentrations would produce zones of inhibition. Only a few alterations in routine laboratory procedure were required to perform the assays. Use of these assays should assure a milk supply that would not cause allergic reactions in humans or significantly inhibit dairy starter cultures. The general principal of “critical” concentration might have applications other than those that we have described, to increase the sensitivity of radial-diffusion analyses for biologically active compounds.

Improved Spectrophotometric Determination of Cyclopiazonic Acid in Poultry Feed and Corn

1990 ◽  
Vol 73 (2) ◽  
pp. 257-259 ◽  
Author(s):  
Ivan Chang-Yen ◽  
Keshore Bidasee
Keyword(s):  
Detection Limit ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Cyclopiazonic Acid ◽  
Poultry Feed ◽  
Reaction Conditions ◽  
Lower Detection Limit ◽  
Lower Detection ◽  
Feed Samples

Abstract An improved visible spectrophotometric method has been developed for cyclopiazonic acid in poultry feed and corn. The method Is based on the reaction of cyclopiazonic acid with Ehrlich reagent and detection at 580 nm. Reaction conditions were optimized with respect to reaction and measurement times and acid and Ehrlich reagent concentrations. Calibration curves were linear from 1 to 20 μg cyclopiazonic acid in 3 mL Ehrlich reagent, with a lower detection limit of 0.08 mg/kg for 50 g samples of poultry feed and corn. Recoveries from 50 g samples of poultry feed spiked with cyclopiazonic ranging from 0.16 to 1.20 mg/kg averaged 93.8%. Moldy corn and poultry feed samples analyzed by this method contained between 1 and 4 mg/kg cyclopiazonic acid.

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