scholarly journals Determination of Sulfamethazine in Milk by Biosensor Immunoassay

1999 ◽  
Vol 82 (6) ◽  
pp. 1316-1320 ◽  
Author(s):  
Valérie Gaudin ◽  
Marie-Laure Pavy
Keyword(s):  
Polyclonal Antibodies ◽  
Gold Surface ◽  
Cross Reactivity ◽  
Antibody Concentration ◽  
Optimal Conditions ◽  
Maximum Residue Limit ◽  
Antibiotic Concentration ◽  
Flow Rates ◽  
Carboxymethyl Dextran

Abstract A biosensor based on surface plasmon resonance (SPR) measurement was developed for use in an immunoassay for detection of sulfamethazine (SMZ) in milk. The biospecific surface was a carboxymethyl dextran¯modified gold-surface sensor chip to which SMZ was covalently bound. The assay was based on inhibition of the binding of polyclonal antibodies to immobilized SMZ by SMZ in the sample. The SPR response changed inversely in relation to the antibiotic concentration in the sample. Calibration curves were constructed for SMZ in buffer and in milk at a concentration which included the maximum residue limit (0 to 200 μg/kg). The analysis time per sample varied from 8 to 30 min. Different flow rates and antibodies were modified alternatively during the study to assess their influence on the performance of the assay. The active antibody concentration was calculated at approximately 1880 and 180 nM for the antibody anti-SMZ 1 and the antibody anti-SMZ 2, respectively. No cross-reactivity of antibodies with other antibiotics was found. Under optimal conditions, the detection limits in milk for SMZ were 8 and 1.7 μg/kg, respectively, for antibody 1 and antibody 2, at a flow rate of 20 μL/min.

Flame Atomic Absorption Spectrometric Determination of Gold After Solid-Phase Extraction of Its 2-Aminobenzothiazole Complex on Diaion SP-207

2016 ◽  
Vol 99 (2) ◽  
pp. 534-538 ◽  
Author(s):  
Yunus Emre Unsal ◽  
Mustafa Tuzen ◽  
Mustafa Soylak
Keyword(s):  
Solid Phase ◽  
Sample Volume ◽  
Mine Soil ◽  
Optimal Conditions ◽  
Flow Rates ◽  
Column System ◽  
Flame Atomic Absorption ◽  
Atomic Absorption Spectrometric ◽  
Type Sample

Abstract An SPE of Au (III) on a 2-aminobenzothiazole–coated Diaion SP 207-column system has been developed. The parameters, including pH of solution, amount of 2-aminobenzothiazole, eluent type, sample volume, and flow rates, were examined. The effects of alkali, alkali earth, and some metals were also studied. The recovery values at optimal conditions and detection limits for Au (III) were found as >95% and 3.8 μg L−1, respectively. The factor of preconcentration was 250. The RSD value was <5%. The capacity of adsorption for the resin was 10.4 mg g−1. The accuracy of the method was evaluated by the use of CDN-GS-3D gold-certified reference material. The proposed procedure for the determination of gold was applied to water, mine, soil, and anodic slime samples.

Development of an Analytical Protocol for the Determination of Polybrominated Biphenyls in Water by Enzyme-Linked Immunosorbent Assay

2011 ◽  
Vol 347-353 ◽  
pp. 1537-1541 ◽  
Author(s):  
Han Yu Chen ◽  
Hui Sheng Zhuang
Keyword(s):  
Detection Limit ◽  
Quantitative Determination ◽  
Incubation Time ◽  
Polyclonal Antibodies ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antibody Concentration ◽  
Polybrominated Biphenyls ◽  
Analytical Protocol ◽  
Optimized Conditions

A novel immunoassay has been developed for the quantitative determination of polybrominated biphenyls (PBBs) using indirect competitive format. A new method was developed to synthesize PBBs congener (PCB15) hapten and its artificial immunogen, then the polyclonal antibodies. The assay was optimized concerning the coating conjugate and antibody concentration, incubation time and temperature, the tolerance to organic solvents and so on. Under optimized conditions, PBB15 can be determined in the concentration range of 0.01-100 μg L-1 with a detection limit of 0.02 μg L-1. The cross-reactivities of the assays were below 8%. While water samples could be analyzed directly.

scholarly journals Development of Nanozyme-Labeled Biomimetic Immunoassay for Determination of Sulfadiazine Residue in Foods

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jingbo He ◽  
Li Zhang ◽  
Longhua Xu ◽  
Feifan Kong ◽  
Zhixiang Xu
Keyword(s):  
High Performance ◽  
Detection Method ◽  
Limit Of Detection ◽  
Milk Powder ◽  
Template Molecule ◽  
Optimal Conditions ◽  
Maximum Residue Limit ◽  
Imprinted Polymer ◽  
Milk Samples

The excessive use and ingestion of residues of sulfonamides harm the human body and the environment. To meet the requirements of the maximum residue limit specified by the Ministry of Agriculture of China, a rapid detection method urgently needs to be developed. In the present study, a molecularly imprinted polymer (MIP) that could selectively recognize sulfadiazine (SDZ) was prepared using SDZ as the template molecule and methacrylic acid as the functional monomer. Using MIP as biomimetic antibody and Au@Pt@SiO2 nanozyme as a marker, a new biomimetic immunoassay was developed to detect sulfadiazine. Under the optimal conditions, the limit of detection (IC15) and sensitivity (IC50) of this method were 0.09 and 6.1 mg/L, respectively. To determine the accuracy of this method, honey and milk samples spiked with sulfadiazine were analyzed, with recoveries in the range of 70.8%-90.2%. The method was also used for the quantitative analysis of sulfadiazine residues in milk powder and milk samples, producing results which correlated well with those obtained by high-performance liquid chromatography.

scholarly journals Express determination of cephalexin

2021 ◽  
Vol 21 (3) ◽  
pp. 260-266
Author(s):  
Anastasiia V. Tumskaia ◽  
◽  
Irina V. Kosyreva ◽  
Keyword(s):  
Detection Limit ◽  
Linear Dependence ◽  
Quantitative Assessment ◽  
Heating Time ◽  
Test Methods ◽  
Test Method ◽  
Optimal Conditions ◽  
Antibiotic Concentration ◽  
Blue Channel

Test means based on immobilized Fehling’s reagent for the determination of cephalexin have been obtained. Methods for visual and colorimetric assessment of antibiotic concentration using a smartphone camera have been developed. The optimal conditions for the indicator reaction have been selected with varying heating time and temperature. For a visual semi-quantitative assessment of the content of cephalexin, a color scale has been obtained. The metrological characteristics of the test method have been determined: the range of the determined contents is 0.5–16 mg/ml, the unreliability interval is 0.1–0.4 mg/ml, and the detection limit is 0.4 mg / ml. For the colorimetric assessment of the concentration of cephalexin, a linear dependence of the intensity of the Blue channel on the logarithm of the concentration of cephalexin (у = –96x + 144, r 2 = 0.99) has been constructed, and linear dependences of the area (у = –36986x + 62458, r 2 = 0.96) and perimeter (у = –270x + 786, r 2 = 0.93) from the logarithm of the concentration of cephalexin have been obtained. The range of the determined contents was 0.1–16 mg/ml, the lower limit was 0.1 mg / ml. The verification of the correctness of the developed test methods was carried out by the «introduced-found» method (Sr  0.13).

Immunocytochemical methodology for the localization of neuronal antigens at the ultrastructural level

1990 ◽  
Vol 48 (3) ◽  
pp. 876-877
Author(s):  
Jorge Pecci Saavedra ◽  
Mark Connaughton ◽  
Juan José López ◽  
Alicia Brusco
Keyword(s):  
Spinal Cord ◽  
Substantia Nigra ◽  
Polyclonal Antibodies ◽  
Ultrastructural Level ◽  
Point Of View ◽  
Nerve Tissue ◽  
Tissue Fixation ◽  
Optimal Conditions ◽  
Interpeduncular Nucleus ◽  
Technical Point

The use of antibodies as labels for the localization of specific molecules in the nervous systan has been extensively applied in recent years. Both monoand polyclonal antibodies or antisera have been employed. The knowledge of the organization of neuronal connectivities, gliovascular relationships, glioneuronal relationships and other features of nerve tissue has greatly increased.A number of areas of the nervous systan have been analyzed in our laboratory, including the nuclei of the raphe system, the reticular formation, interpeduncular nucleus, substantia nigra, caudate nucleus, putamen, pallidum, spinal cord, pineal gland and others.From a technical point of view, a number of variables needed to be taken into account in order to obtain reliable and reproducible results. The design of the optimal conditions of tissue fixation, embedding, sectioning, dilution of antibodies, and adaptation of Sternberger PAP technique were sane of the parameters taken into account to optimize the results. It is critical that each step of the technique be defined for each particular case.

Human Prothrombin Activation: Determination of Plasma and Serum Levels of Prothrombin Fragment 3 by Radioimmunoassay

1979 ◽  
Author(s):  
Daniel Walz ◽  
Thomas Brown
Keyword(s):  
Blood Clotting ◽  
Factor Xa ◽  
Heart Association ◽  
Serum Levels ◽  
Cross Reactivity ◽  
Assay Procedure ◽  
A Chain ◽  
Prothrombin Activation ◽  
Theoretical Amount

Human prothrombin activation is unique in that, in addition to the release of fragment 1.2 (FI.2) from the NH-terminus of prothrombin by factor Xa during the generation of thrombin, an additional 13 residue polypeptide, fragment 3 (F3), is autocatalytically removed from the amino-terminus of the thrombin A chain. We have developed a rapid radioimmunoassay for human F3 which incorporates short incubation times and the use of a preprecipitated second antibody; the assay can be performed in three hours. Specificity studies in buffer systems show prothrombin and prethrombin 1 cross-reacting at a level of 0.001; purified thrombin does not cross-react. In the presence of 5% BSA, prothrombin displays considerably less cross-reactivity. No immunoreactive material to F3 antibodies could be detected in 400 μL of plasma. Serum, obtained from whole blood clotting, contained measurable quantities of F3 (40-100 ng/mL). This amount in serum represents only 5-10% of the theoretical amount available should all of the fragment be hydrolytically cleaved during the conversion of prothrombin to thrombin. This assay procedure is currently being utilized to monitor the activation of purified human prothrombin in the absence and presence of selected plasma inhibitors. (Supported in part by NIH 05384-17 and the Michigan Heart Association).

Spectrophotometric study of the complexation equilibria of cadmium ions with 5-bromo and 5-chloro derivatives of 2-(2-pyridylazo)-5-diethylaminophenol (BrPADAP, ClPADAP)

1983 ◽  
Vol 48 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Miroslav Macka
Keyword(s):  
Equilibrium Constants ◽  
Spectrophotometric Study ◽  
Graphical Analysis ◽  
Optimal Conditions ◽  
Cadmium Ions ◽  
Brij 35 ◽  
Ethanol Medium ◽  
Triton X ◽  
Derivatives Of

The composition, optical characteristics, molar absorption coefficients and equilibrium constants of the reactions of formation of the ML and ML2 complexes of both reagents with cadmium(II) ions were determined by graphical analysis and numerical interpretation of the absorbance-pH curves by the modified SQUAD-G program. Optimal conditions were proposed for the spectrophotometric determination of Cd in 10% v/v ethanol medium in the presence of 0.1% w/v Triton X-100 or 1% w/v Brij 35. BrPADAP and ClPADAP are the most sensitive spectrophotometric reagents for the determination of cadmium(II) ions (ε = 1.28-1.44 . 105 mmol-1 cm2 at 560 nm and pH 8.0-9.5) with a high colour contrast in the reaction (Δλmax ~117 nm) and a selectivity similar to that of other N-heterocyclic azodyes (PAR, PAN, etc.).

Spectrophotometric study of the reactions of lanthanoids with bromopyrogallol red in the presence of cation active tensides

1982 ◽  
Vol 47 (2) ◽  
pp. 503-508 ◽  
Author(s):  
Irena Němcová ◽  
Pavla Plocková ◽  
Tran Hong Con
Keyword(s):  
Absorption Spectra ◽  
Photometric Determination ◽  
Spectrophotometric Study ◽  
Ternary Complexes ◽  
Optimal Conditions ◽  
Bromopyrogallol Red ◽  
Binary Complexes

The absorption spectra of the binary complexes of lanthanoids with bromopyrogallol red were measured and the formation of ternary complexes with cation active tenside, Septonex, was studied. Optimal conditions were found for the formation of these complexes and the possibility of their use in the photometric determination of lanthanoids was demonstrated on several examples.

Determination of specific interfacial areas in swirled two-phase flow

1983 ◽  
Vol 48 (3) ◽  
pp. 842-853
Author(s):  
Kurt Winkler ◽  
František Kaštánek ◽  
Jan Kratochvíl
Keyword(s):  
Interfacial Area ◽  
Liquid Volume ◽  
Upward Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Mist Flow ◽  
Interfacial Areas ◽  
Correlation Parameters ◽  
Flow Components

Specific gas-liquid interfacial area in flow tubes 70 mm in diameter of the length 725 and 1 450 mm resp. containing various swirl bodies were measured for concurrent upward flow in the ranges of average gas (air) velocities 11 to 35 ms-1 and liquid flow rates 13 to 80 m3 m-2 h-1 using the method of CO2 absorption into NaOH solutions. Two different flow regimes were observed: slug flow swirled annular-mist flow. In the latter case the determination was carried out separately for the film and spray flow components, respectively. The obtained specific areas range between 500 to 20 000 m3 m-2. Correlation parameters are energy dissipation criteria, related to the geometrical reactor volume and to the static liquid volume in the reactor.

The polarographic and voltammetric determination of 2,6-dicyano-4-nitro-2'-acetylamino-4'-diethylaminoazobenzene

1990 ◽  
Vol 55 (6) ◽  
pp. 1508-1517 ◽  
Author(s):  
Jiří Barek ◽  
Dagmar Civišová ◽  
Ashutosh Ghosh ◽  
Jiří Zima
Keyword(s):  
Azo Dye ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Determination Limit ◽  
Polarographic Reduction ◽  
Hanging Mercury Drop Electrode ◽  
Optimal Conditions ◽  
Pulse Polarography ◽  
Pulse Voltammetry

The polarographic reduction of the title azo dye was studied and optimal conditions were found for its analytical utilization in the concentration range 1 . 10-6 - 1 . 10-7 mol l-1 using differential pulse polarography and 1 . 10-6 - 1 . 10-8 mol l-1 using fast scan differential pulse voltammetry or linear scan voltammetry at a hanging mercury drop electrode. When the latter technique is combined with adsorptive accumulation of the studied substance on the surface of the hanging mercury drop, the determination limit can be further decreased to 3 . 10-9 mol l-1.

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