scholarly journals Indirect Competitive Determination of Tetracycline Residue in Honey Using an Ultrasensitive Gold-Nanoparticle-Linked Aptamer Assay

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2144 ◽  
Author(s):  
Yan-Mei Sheng ◽  
Jian Liang ◽  
Jing Xie
Keyword(s):  
Gold Nanoparticles ◽  
Food Safety ◽  
Bovine Serum Albumin ◽  
Peroxidase Activity ◽  
Limit Of Detection ◽  
High Accuracy ◽  
Important Food ◽  
Bovine Serum Albumin Conjugate ◽  
Aptamer Assay

Tetracycline residue in honey has become an increasingly important food safety problem. In this work, an ultrasensitive gold nanoparticles (AuNPs)-linked aptamer assay was developed to determine the tetracycline residue in honey. First, a tetracycline–bovine serum albumin conjugate coating was applied to a microplate. Then, with the incubation of AuNPs-linked aptamer, the fixed tetracycline in the microplate competed for the limited aptamer with the free tetracycline in the sample. Higher amounts of free tetracycline in the sample were associated with more competitive binding of aptamer-AuNPs, and the aptamer-AuNPs binding with tetracycline-BSA was lower. Finally, as a kind of nanozyme, AuNPs exhibited peroxidase activity and oxidized 3,3′,5,5′-tetramethylbenzidine, transforming it from colorless to blue, and achieving the measurement at 652 nm. The analytical performance—including linearity, limit of detection, selectivity, precision, repeatability, and accuracy—has been investigated. It was successfully applied to the determination of tetracycline in honey samples with high accuracy and sensitivity.

Indirect Determination of Amikacin by Gold Nanoparticles as Redox Probe

2020 ◽  
Vol 17 ◽  
Author(s):  
Mansureh Alizadeh ◽  
Mandana Amiri ◽  
Abolfazl Bezaatpour
Keyword(s):  
Gold Nanoparticles ◽  
Bacterial Infections ◽  
Limit Of Detection ◽  
Pharmaceutical Preparation ◽  
Cathodic Peak ◽  
Easy Method ◽  
Peak Current ◽  
Indirect Determination ◽  
Tract Infections

: Amikacin is an aminoglycoside antibiotic used for many gram-negative bacterial infections like infections in the urinary tract, infections in brain, lungs and abdomen. Electrochemical determination of amikacin is a challenge in electroanalysis because it shows no voltammetric peak at the surface of bare electrodes. In this approach, a very simple and easy method for indirect voltammetric determination of amikacin presented in real samples. Gold nanoparticles were electrodeposited at the surface of glassy carbon electrode in constant potential. The effect of several parameters such as time and potential of deposition, pH and scan rates on signal were studied. The cathodic peak current of Au3+ decreased with increasing amikacin concentration. Quantitative analysis of amikacin was performed using differential pulse voltammetry by following cathodic peak current of gold ions. Two dynamic linear ranges of 1.0 × 10−8–1.0 × 10-7 M and 5.0 × 10−7–1.0 × 10-3 M were obtained and limit of detection was estimated 3.0× 10−9 M. The method was successfully determined amikacin in pharmaceutical preparation and human serum. The effect of several interference in determination of amikacin was also studied.

Direct radioimmunoassay of 6-sulfatoxymelatonin in plasma with use of an iodinated tracer

1991 ◽  
Vol 37 (4) ◽  
pp. 536-539 ◽  
Author(s):  
Catherine Harthé ◽  
Bruno Claustrat ◽  
Jocelyne Brun ◽  
Guy Chazot
Keyword(s):  
Plasma Sample ◽  
Limit Of Detection ◽  
Circadian Variation ◽  
Hepatic Metabolism ◽  
Pharmaceutical Formulations ◽  
Practical Application ◽  
Bovine Serum Albumin Conjugate ◽  
Preliminary Study ◽  
Related Compounds

Abstract We describe here a direct a radioimmunoassay (RIA) for the determination of 6-sulfatoxymelatonin (aMT6s) in plasma, with iodinated aMT6s as tracer. The aMT6s antiserum was raised in rabbit by immunization with a bovine serum albumin conjugate, giving negligible cross-reactivities for related compounds. The low limit of detection (15 pmol/L) allowed a direct assay that required only a 100-microL plasma sample. Dilutions of plasma and of synthetic aMT6s gave the same parallel response in the RIA. A preliminary study showed a circadian variation in healthy volunteers, with mean concentrations ranging from 52 (at 1600-2100 h) to 378 pmol/L (at 0400 h), whereas this rhythm was abolished in pinealomectomized patients. After administration of melatonin orally, or by infusion, the aMT6s concentrations in plasma concorded with previous data on aMT6s production and pharmacokinetics, with aMT6s being cleared from plasma more slowly than melatonin. This assay should have practical application in the development of new pharmaceutical formulations that minimize the hepatic metabolism of melatonin.

scholarly journals Gold Nanoparticles with Different Particle Sizes for the Quantitative Determination of Chlorpyrifos Residues in Soil by SERS

2019 ◽  
Vol 20 (11) ◽  
pp. 2817 ◽  
Author(s):  
Yong He ◽  
Shupei Xiao ◽  
Tao Dong ◽  
Pengcheng Nie
Keyword(s):  
Gold Nanoparticles ◽  
Limit Of Detection ◽  
Soil Surface ◽  
Surface Enhanced Raman Spectroscopy ◽  
Sers Substrate ◽  
Least Squares Regression ◽  
Simple Method ◽  
Good Linear ◽  
Relative Standard

Chlorpyrifos (CPF) is widely used in the prevention and control of crop pests and diseases in agriculture. However, the irrational utilization of pesticides not only causes environmental pollution but also threatens human health. Compared with the conventional techniques for the determination of pesticides in soil, surface-enhanced Raman spectroscopy (SERS) has shown great potential in ultrasensitive and chemical analysis. Therefore, this paper reported a simple method for synthesizing gold nanoparticles (AuNPs) with different sizes used as a SERS substrate for the determination of CPF residues in soil for the first time. The results showed that there was a good linear correlation between the SERS characteristic peak intensity of CPF and particle size of the AuNPs with an R2 of 0.9973. Moreover, the prepared AuNPs performed great ultrasensitivity, reproducibility and chemical stability, and the limit of detection (LOD) of the CPF was found to be as low as 10 μg/L. Furthermore, the concentrations ranging from 0.01 to 10 mg/L were easily observed by SERS with the prepared AuNPs and the SERS intensity showed a good linear relationship with an R2 of 0.985. The determination coefficient (Rp2) reached 0.977 for CPF prediction using the partial least squares regression (PLSR) model and the LOD of CPF residues in soil was found to be as low as 0.025 mg/kg. The relative standard deviation (RSD) was less than 3.69% and the recovery ranged from 97.5 to 103.3%. In summary, this simple method for AuNPs fabrication with ultrasensitivity and reproducibility confirms that the SERS is highly promising for the determination of soil pesticide residues.

scholarly journals Tannic Acid-Capped Gold Nanoparticles as a Novel Nanozyme for Colorimetric Determination of Pb2+ Ions

Chemosensors ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 332
Author(s):  
Kseniya V. Serebrennikova ◽  
Nadezhda S. Komova ◽  
Anna N. Berlina ◽  
Anatoly V. Zherdev ◽  
Boris B. Dzantiev
Keyword(s):  
Gold Nanoparticles ◽  
Tannic Acid ◽  
Oxidation Reaction ◽  
Limit Of Detection ◽  
Colorimetric Sensor ◽  
Spring Water ◽  
Colorimetric Determination ◽  
Highly Sensitive ◽  
Maximal Sensitivity

In this study, tannic acid-modified gold nanoparticles were found to have superior nanozyme activity and catalyze the oxidation reaction of 3,3′,5,5′-tetramethylbenzidine in the presence of hydrogen peroxide. Enhancing the catalytic activity of the nanozyme by Pb2+ ions caused by selectively binding metal ions by the tannic acid-capped surface of gold nanoparticles makes them an ideal colorimetric probe for Pb2+. The parameters of the reaction, including pH, incubation time, and concentration of components, were optimized to reach maximal sensitivity of Pb2+ detection. The absorption change is directly proportional to the Pb2+ concentration and allows the determination of Pb2+ ions within 10 min. The colorimetric sensor is characterized by a wide linear range from 25 to 500 ng×mL−1 with a low limit of detection of 11.3 ng×mL−1. The highly sensitive and selective Pb2+ detection in tap, drinking, and spring water revealed the feasibility and applicability of the developed colorimetric sensor.

scholarly journals Development of Aflatoxin B1-Lysine Adduct Monoclonal Antibody for Human Exposure Studies

2001 ◽  
Vol 67 (6) ◽  
pp. 2712-2717 ◽  
Author(s):  
Jia-Sheng Wang ◽  
Salahaddin Abubaker ◽  
Xia He ◽  
Guiju Sun ◽  
Paul T. Strickland ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
High Risk ◽  
Bovine Serum Albumin ◽  
Dna Adducts ◽  
Human Exposure ◽  
Limit Of Detection ◽  
Serum Samples ◽  
Bovine Serum Albumin Conjugate ◽  
Aflatoxin B

ABSTRACT Mouse monoclonal antibodies were developed against a synthetic aflatoxin B1 (AFB)-lysine–cationized bovine serum albumin conjugate. The isotype of one of these antibodies, IIA4B3, has been classified as immunoglobulin G1(λ). The affinity and specificity of IIA4B3 were further characterized by a competitive radioimmunoassay. The affinities of IIA4B3 for AFB and its associated adducts and metabolites are ranked as follows: AFB-lysine > 8,9-dihydro-8-(2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl formamido)-9-hydroxy-AFB > AFB = 8,9-dihydro-8-(N 7-guanyl)-9-hydroxy-AFB > aflatoxin M1 > aflatoxin Q1. IIA4B3 had about a 10-fold higher affinity for binding to AFB-lysine adduct than to AFB when 3H-AFB–lysine was used as the tracer. The concentration for 50% inhibition for AFB-lysine was 0.610 pmol; that for AFB was 6.85 pmol. IIA4B3 had affinities at least sevenfold and twofold higher than those of 2B11, a previously developed antibody against parent AFB, for the major aflatoxin-DNA adducts 8,9-dihydro-8-(N 7-guanyl)-9-hydroxy-AFB and 8,9-dihydro-8-(2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl formamido)-9-hydroxy-AFB, respectively. An analytical method based on a competitive radioimmunoassay with IIA4B3 and3H-AFB–lysine was validated with a limit of detection of 10 fmol of AFB-lysine adduct. The method has been applied to the measurement of AFB-albumin adduct levels in human serum samples collected from the residents of areas at high risk for liver cancer.

scholarly journals Simple Spectrophotometric Determination of Torsemide in Bulk Drug and in Formulations

2008 ◽  
Vol 5 (3) ◽  
pp. 473-478 ◽  
Author(s):  
Marothu Vamsi Krishna ◽  
Dannana Gowri Sankar
Keyword(s):  
Limit Of Detection ◽  
Regression Line ◽  
Cost Effective ◽  
Pharmaceutical Formulations ◽  
High Accuracy ◽  
Molar Absorptivity ◽  
Good Precision ◽  
Experimental Parameters ◽  
Bulk Drug

A simple and cost effective spectrophotometric method is described for the determination of torsemide in pure form and in pharmaceutical formulations. The method is based on the formation of blue colored chromogen when the drug reacts with Folin-Ciocalteu (F-C) reagent in alkaline medium. The colored species has an absorption maximum at 760 nm and obeys beer's law in the concentration range 30 – 150 ug mL−1. The absorbance was found to increase linearly with increasing concentration of TSM, which is corroborated by the calculated correlation coefficient value of 0.9999 (n=8). The apparent molar absorptivity and sandell sensitivity were 1.896×103L mol−1cm−1and 0.183 μg cm−2, respectively. The slope and intercept of the equation of the regression line are 5.4x10−3and 1.00×10−4respectively. The limit of detection was 0.94.The optimum experimental parameters for the reaction have been studied. The validity of the described procedure was assessed. Statistical analysis of the results has been carried out revealing high accuracy and good precision. The proposed method was successfully applied to the determination of TSM in pharmaceutical formulations.

An enhanced enzyme-linked aptamer assay for the detection of zearalenone based on gold nanoparticles

2021 ◽  
Author(s):  
Shumin Sun ◽  
Yanli Xie
Keyword(s):  
Gold Nanoparticles ◽  
Signal Amplification ◽  
Competitive Assay ◽  
Aptamer Assay ◽  
Sensitive Determination

Enhanced enzyme-linked aptamer assay (ELAA) for rapid and sensitive determination of zearalenone (ZEN) was established based on HRP signal amplification by using a AuNP modified aptamer as a probe in a competitive assay.

scholarly journals Modulating Linker Composition of Haptens Resulted in Improved Immunoassay for Histamine

Biomolecules ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 597 ◽  
Author(s):  
Lin Luo ◽  
Xiao-Qun Wei ◽  
Bao-Zhu Jia ◽  
Jin-Yi Yang ◽  
Yu-Dong Shen ◽  
...  
Keyword(s):  
Small Molecules ◽  
Limit Of Detection ◽  
Food Samples ◽  
Important Food ◽  
Buffer Solution ◽  
Protein Conjugates ◽  
Inhibition Concentration ◽  
Hapten Design ◽  
Direct Derivatization

Histamine (HA) is an important food contaminant generated during food fermentation or spoilage. However, an immunoassay for direct (derivatization free) determination of HA has rarely been reported due to its small size to induce the desired antibodies by its current hapten-protein conjugates. In this work, despite violating the classical hapten design criteria which recommend introducing a linear aliphatic (phenyl free) linker into the immunizing hapten, a novel haptens, HA-245 designed and synthesized with a phenyl-contained linker, exhibited significantly enhanced immunological properties. Thus, a quality-improved monoclonal antibody (Mab) against HA was elicited by its hapten-carrier conjugates. Then, as the linear aliphatic linker contained haptens, Hapten B was used as linker-heterologous coating haptens to eliminate the recognition of linker antibodies. Indirect competitive ELISA (ic-ELISA) was developed with a 50% inhibition concentration (IC50) of 0.21 mg/L and a limit of detection (LOD) of 0.06 mg/L in buffer solution. The average recoveries of HA from spiked food samples for this ic-ELISA ranged from 84.1% and 108.5%, and the analysis results agreed well with those of referenced LC-MS/MS. This investigation not only realized derivatization-free immunoassay for HA, but also provided a valuable guidance for hapten design and development of immunoassay for small molecules.

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