scholarly journals Selective capturing of phenolic derivative by a binary metal oxide microcubes for its detection

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mohammed Muzibur Rahman
Keyword(s):  
Detection Limit ◽  
Dynamic Range ◽  
Electrochemical Performances ◽  
Electron Mediator ◽  
Limit Of Quantification ◽  
Electrochemical Approach ◽  
Binary Metal Oxide ◽  
Conducting Coating ◽  
Ultra Trace ◽  
Binary Material

AbstractDevelopment of highly efficient and potential material for toxic p-nitrophenol is an important design for sensitive detection of hazardous species from ecology and environment. Here it is developed, an efficient as well as selective of p-nitrophenol using binary material by electrochemical performances, including good linearity, lower detection limit, good stability, higher reproducibility and extreme sensitivity. The prepared electrode was fabricated by immobilization of SnO2/CdO microcubes (MCs) with conducting coating binders by using well-known glassy carbon electrode (GCE). The proposed MCs with SnO2/CdO were well-functionalized and prepared by facile hydrothermal technique. The general instrumentation namely, FTIR, UV/vis, FESEM, XPS, TEM, EDS, and powder XRD were employed for the morphological evaluation of the prepared doped MCs, structural, optical and elemental analyses. The large dynamic range (LDR) from 1.0 to 0.01 mM with 0.13 pM detection limit (S/N = 3), limit of quantification (LOQ; 0.43 pM), and an excellent sensitivity of 7.12 µAµM−1cm−2 were exhibited by the fabricated binary material based on SnO2/CdO MCs for selective p-nitrophenol capturing. In shortly, the SnO2/CdO MCs can be employed as an efficient electron mediator with binary materials fabricated GCE for capturing the p-nitrophenol at ultra-trace amounts. Then the binary synthesized material of SnO2/CdO MCs is used as potential and sensitive sensor layer by stable electrochemical approach for sensitive capturing of toxic p-nitrophenol from environmental samples.

Comparative performances of phenolic sensors based on various CeO2-carbon material nanocomposites for environmental safety

Sensor Review ◽  
2018 ◽  
Vol 38 (4) ◽  
pp. 467-477 ◽  
Author(s):  
Faisal K. Algethami ◽  
Hadi M. Marwani ◽  
Abdullah M. Asiri ◽  
Mohammed M. Rahman
Keyword(s):  
Detection Limit ◽  
Carbon Material ◽  
Chemical Sensor ◽  
Ultra Violet ◽  
Limit Of Quantification ◽  
Content Type ◽  
Electrochemical Approach ◽  
Vis Spectroscopy ◽  
Wet Chemical ◽  
Sensor Probe

Purpose The purpose of this study is to prepare various CeO2-based carbon material (CNT, CB, GO) nanocomposites through a wet chemical process for the development of a sensor probe to detect various environmental toxins by using an electrochemical approach under room temperature conditions. A comparative study on sensitive and selective phenolic sensor (4-methoxyphenol; 4-MP) has been fabricated by modifying a glassy carbon electrode (GCE) with various nanocomposites (NCs) such as CeO2, CeO2–CNT (carbon nanotubes), CeO2–CB (carbon black) and CeO2–GO (graphene oxide) NCs. Design/methodology/approach The CeO2–CNT NCs were prepared by the wet chemical method at low temperature. NCs were characterized by various methods such as transmission electron microscopy (TEM), Fourier-transform infra-red (FTIR), ultra-violet/visible (UV-Vis) spectroscopy and XRD (X-ray diffraction). CeO2–CNT NCs were immobilized as a film on the flat surface of the GCE by using binders (5% Nafion). The electrochemical measurements of the 4-MP detection with the CeO2–CNT NCs/Nafion/GCE sensor were studied by the current-voltage method. Findings In the optimal conditions, the sensitivity, detection limit and limit of quantification of 4-MP sensor probe were found to be 47.56 µAcm-2 µM−1, 12.0 ± 0.2 nM and 40.0 ± 0.5 nM (S/N of 3), respectively. Research limitations/implications This electrochemical sensor showed an acceptable analytical performance in the detection of 4-MP with higher sensitivity, lower detection limit, large dynamic concentration range, good reproducibility and fast response time. Practical implications This electrochemical approach can be applied practically for the determination of selective 4-MP in real environmental and extracted samples. Social implications CeO2–CNT NCs/Nafion/GCE sensor probe was used for the safety of environmental and health-care fields at larger scales. Originality/value This electrochemical approach is a significant achievement on the development of sensor probe. The results are indicated as being technically detailed with an up-to-date account of recent chemical sensor research studies.

scholarly journals Surfactant modified carbon nanotube paste electrode for the sensitive determination of mitoxantrone anticancer drug

2017 ◽  
pp. 39 ◽  
Author(s):  
Jamballi G. Manjunatha
Keyword(s):  
Cyclic Voltammetry ◽  
Carbon Nanotube ◽  
Detection Limit ◽  
Dynamic Range ◽  
Sodium Dodecyl ◽  
High Sensitivity ◽  
Current Response ◽  
Limit Of Quantification ◽  
Carbon Nanotube Paste Electrode ◽  
Paste Electrode

<p class="PaperAbstract"><span lang="EN-US">Surfactant modified carbon nanotube paste electrode is prepared as electrochemical sensor with high sensitivity in responding to Mitoxantrone (MTX). Electrochemical oxidation of MTX is investigated in buffered solution by cyclic voltammetry that is found very sensitive method for detection of MTX. It is shown that the sodium dodecyl sulfate modified carbon nanotube paste electrode (SDSMCNTPE) gives enhanced current response for MTX compared to the bare carbon nanotube paste electrode (BCNTPE). Different parameters were tested to optimize the conditions for MTX determination. The effects of different surfactant and surfactant concentration, pH, scan rate, detection limit (LOD), limit of quantification (LOQ) and concentration of MTX on the oxidation peak current values were determined. Excellent results were obtained by cyclic voltammetry using SDSMCNTPE, where two MTX oxidation peaks appeared at 367 and 596 mV </span><span lang="EN-US">vs.</span><span lang="EN-US"> SCE. Detailed analysis of the second voltammetric peak showed the linear dynamic range between 2×10<sup>−7</sup> and 7×10<sup>−6</sup> M MTX with the slope of co-relation coefficient of 0.99271. LOD and LOQ were determined as 3.5 ×10<sup>−8</sup> M and 11×10<sup>−8</sup> M, respectively. The SDSMCNTPE showed very good reproducibility, high stability in its voltammetric response, high electrochemical sensitivity and low detection limit for MTX.</span></p>

scholarly journals A tandem giant magnetoresistance assay for one-shot quantification of clinically relevant concentrations of N-terminal pro-B-type natriuretic peptide in human blood

2021 ◽  
Author(s):  
Fanda Meng ◽  
Weisong Huo ◽  
Jie Lian ◽  
Lei Zhang ◽  
Xizeng Shi ◽  
...  
Keyword(s):  
Detection Limit ◽  
Giant Magnetoresistance ◽  
Dynamic Range ◽  
Point Of Care ◽  
Sample Volume ◽  
Small Sample ◽  
Broad Dynamic Range ◽  
Gmr Sensors ◽  
Gmr Sensor ◽  
Sample Volume Requirement

AbstractWe report a microfluidic sandwich immunoassay constructed around a dual-giant magnetoresistance (GMR) sensor array to quantify the heart failure biomarker NT-proBNP in human plasma at the clinically relevant concentration levels between 15 pg/mL and 40 ng/mL. The broad dynamic range was achieved by differential coating of two identical GMR sensors operated in tandem, and combining two standard curves. The detection limit was determined as 5 pg/mL. The assay, involving 53 plasma samples from patients with different cardiovascular diseases, was validated against the Roche Cobas e411 analyzer. The salient features of this system are its wide concentration range, low detection limit, small sample volume requirement (50 μL), and the need for a short measurement time of 15 min, making it a prospective candidate for practical use in point of care analysis.

scholarly journals Rapid and Sensitive Quantification of Intracellular Glycyl-Sarcosine for Semi-High-Throughput Screening for Inhibitors of PEPT-1

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1019
Author(s):  
Teresa von Linde ◽  
Gzona Bajraktari-Sylejmani ◽  
Walter E. Haefeli ◽  
Jürgen Burhenne ◽  
Johanna Weiss ◽  
...  
Keyword(s):  
Sample Preparation ◽  
High Throughput ◽  
High Throughput Screening ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Peptide Bond ◽  
Peptide Transporter ◽  
Systemic Absorption ◽  
Screening Assay ◽  
Limit Of Quantification

The peptide transporter PEPT-1 (SLC15A1) plays a major role in nutritional supply with amino acids by mediating the intestinal influx of dipeptides and tripeptides generated during food digestion. Its role in the uptake of small bioactive peptides and various therapeutics makes it an important target for the investigation of the systemic absorption of small peptide-like active compounds and prodrug strategies of poorly absorbed therapeutics. The dipeptide glycyl-sarcosine (Gly-Sar), which comprises an N-methylated peptide bond that increases stability against enzymatic degradation, is widely utilized for studying PEPT-1-mediated transport. To support experiments on PEPT-1 inhibitor screening to identify potential substrates, we developed a highly sensitive Gly-Sar quantification assay for Caco-2 cell lysates with a dynamic range of 0.1 to 1000 ng/mL (lower limit of quantification 0.68 nM) in 50 µL of cell lysate. The assay was validated following the applicable recommendations for bioanalytic method validation of the FDA and EMA. Sample preparation and quantification were established in 96-well cell culture plates that were also used for the cellular uptake studies, resulting in a rapid and robust screening assay for PEPT-1 inhibitors. This sample preparation principle, combined with the high sensitivity of the UPLC-MS/MS quantification, is suitable for screening assays for PEPT-1 inhibitors and substrates in high-throughput formats and holds the potential for automation. Applicability was demonstrated by IC50 determinations of the known PEPT-1 inhibitor losartan, the known substrates glycyl-proline (Gly-Pro), and valaciclovir, the prodrug of aciclovir, which itself is no substrate of PEPT-1 and consequently showed no inhibition in our assay.

Preparation and Immunological Traits of Monoclonal Antibody against Sarafloxacin

2012 ◽  
Vol 459 ◽  
pp. 54-57
Author(s):  
Guo Ying Fan ◽  
Jin Qing Jiang
Keyword(s):  
Monoclonal Antibody ◽  
Detection Limit ◽  
Cell Fusion ◽  
Light Chain ◽  
Dynamic Range ◽  
Fusion Technology ◽  
Alternative Method ◽  
Ic50 Values ◽  
The Stability ◽  
Igg1 Isotype

Through cell fusion technology, five hybridoma lines of sarafloxacin (SAR), named S1-B2, S2-C6, S2-E7, S3-C5, and S3-E5, were identified and their corresponding mAbs were of the IgG1 isotype with a k light chain. The Kaffs of all mAbs were between 2.8 and 4.6×109 L/mol. The titers and IC50 values of purified ascite fluids were in the range of 0.512–2.56×106 and 0.32–0.48 ng/mL, respectively. The performances of S1-B2 and S2-C6 were more consistent in the stability experiments. Based on the S1-B2 hybridoma, an icELISA method was developed. The dynamic range was from 0.004 to 18 ng/mL, with a detection limit for the assay and IC50 values of 0.002 and 0.32 ng/mL, respectively. Therefore, the establishment of these hybridomas may provide an alternative method for the detection of SAR residues in food-original animals.

Development and Validation of HPLC Method for Simultaneous Estimation of Reduced and Oxidized Glutathione in Bulk Pharmaceutical Formulation

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Singh N ◽  
◽  
Akhtar MJ ◽  
Anchliya A ◽  
◽  
...  
Keyword(s):  
Detection Limit ◽  
Limit Of Detection ◽  
Reduced Glutathione ◽  
Pharmaceutical Formulations ◽  
Hplc Method ◽  
Simultaneous Estimation ◽  
Oxidized Glutathione ◽  
Range Limit ◽  
Limit Of Quantification ◽  
Reduced And Oxidized Glutathione

The objective of this study was the development, optimization, and validation of a RP-HPLC method for the quantification of reduced glutathione (GSH) and oxidized glutathione (GSSG) in pharmaceutical formulations The separation utilized a C18 column at room temperature with absorption wavelength 210nm. The mobile phase was an isocratic flow of a 95:5 (v/v) mixture of 25mM phosphate buffer (pH 2.7) and methanol with flow rate at 1.0 mL/min. Validation of the method assessed with the methods ability in seven categories: linearity, range, limit of detection, limit of quantification, accuracy, precision, and selectivity. The method show an acceptable degree of linearity with r²=0.9994 and 0.999 over a concentration range of 10-200 μg/mL for GSH and GSSG respectively. The detection limit and quantification limit for GSH 20.7μg/mL and 69.24μg/mL and for GSSG 17.22μg/mL and 57.42μg/mL respectively. The percent recovery of the method was 99.98-100.93 %. Following validation, the method was employed in the determination of glutathione in pharmaceutical formulations in the form of a liposome. The proposed method offers a simple, accurate, and inexpensive way to quantify reduced glutathione.

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.

118 DEVELOPMENT AND EVALUATION OF A TIME-RESOLVED FLUORESCENCE IMMUNOASSAY FOR ESTRONE-1-SULFATE IN URINE AS A TOOL FOR DIAGNOSIS OF EARLY PREGNANCY IN SWINE

2008 ◽  
Vol 20 (1) ◽  
pp. 139
Author(s):  
Y. S. Park ◽  
S. H. Yang ◽  
S. M. Park ◽  
S. J. Kim ◽  
J. B. Kim
Keyword(s):  
Early Pregnancy ◽  
Field Trial ◽  
Dynamic Range ◽  
Sulfate Concentration ◽  
Fluorescence Immunoassay ◽  
Time Resolved Fluorescence ◽  
Limit Of Quantification ◽  
Time Resolved ◽  
Pregnancy Diagnosis ◽  
Routine Basis

Early identification of pregnancy or non-pregnancy in sows is considered very important, as the management of sows during the post service period is crucial if the breeding efficiency of a herd is to be maximized. Studies of steroid hormones in pregnant sows showed that there was a significant increase in plasma estrone-1-sulfate concentration by the 16th day of gestation, which reaches peak values between Days 23 and 30 of gestation. Since plasma estrone-1-sulfate concentrations are high between Days 23 and 30 of pregnancy, its determination has been used as a means for early pregnancy diagnosis and monitoring fertility in sows. However, the application of the method in pig farms on a routine basis remains restricted because blood sampling is difficult and disturbs the animals. The present study describes the development of a simple and reliable time-resolved fluorescence immunoassay (TR-FIA) method for the estimation of estrone-1-sulfate in swine urine, which was assessed as a means for early diagnosis of pregnancy and monitoring fertility in sows. We demonstrated cross activity between Anti-estrone-1-glucuronide antibody (Clone 155) and estrone-1-sulfate. The method is based on a direct competitive heterogeneous immunoassay by the typical procedure of competitive immunocomplex formation. For detection of estrone-1-sulfate, anti-estrone-1-glucuronide antibody (Clone 155) was first coated on polystyrene microplates, and estrone-1-sulfate was captured by the primary antibody with estrone-1-glucuronide labeled with europium. The immunocomplex was subsequently dissociated by the enhancement solution containing Triton X-100, acetic acid, and chelators. The free europium was detection by DELFIA 1420 detector (Perkin-Elmer Life Sciences, Waltham, MA, USA). The fluorescence intensity of free europium at 613 nm was proportional to the logarithm of the concentration of estron-1-sulfate in a dynamic range of 0.078~10 ng mL–1. Intra-assay variation for estrone-1-sulfate was 4%. The limit of quantification was 100 pg mL–1. The mean estrone-1-sulfate concentration was significantly higher in pregnant sows (15.6 � 5.3 ng mL–1) than in non-pregnant sows and in sows in estrus (0.74 � 0.44 ng mL–1). Taking the concentration of 20 pg mL–1 as a cut-off, all cases of non-pregnant sows and sows in estrus were negative. Urine estrone-1-sulfate concentrations in pregnant sows at 23-day intervals post-service were 14~16 ng mL–1. According to the results of our field trial, urine estrone-1-sulfate concentrations are very low during estrus and remain low in non-pregnant sows at different stages of the estrous cycle, whereas the concentration increases significantly during specific stages of pregnancy at 23-day intervals. It is concluded that the satisfactory sensitivity of the present assay in combination with the good correlation for pregnancy from the present field trial makes this method a very useful technique for early pregnancy diagnosis in swine; the simplicity of urine sampling makes also it suitable for practical use.

scholarly journals Evaluation of Pharmaceutical Quality of Mesalamine Delayed Release Tablets Using a New High Sensitivity Reversed-Phase UPLC Method for its Genotoxic/Aniline Impurity

2011 ◽  
Vol 8 (1) ◽  
pp. 167-179 ◽  
Author(s):  
Rakshit Kanubhai Trivedi ◽  
Mukesh C. Patel
Keyword(s):  
Detection Limit ◽  
Drug Product ◽  
Reversed Phase ◽  
Forced Degradation ◽  
Limit Of Quantification ◽  
Release Formulation ◽  
Pharmaceutical Quality ◽  
Delayed Release ◽  
Run Time

A reversed phase ultra performance liquid chromatography (UPLC) method was developed and validated for the quantification of aniline in mesalamine delayed-release tablets. The optimization of the experimental condition was carried out considering some important requirements like, detection limit, short run time and reproducibility. In the present study, isocratic reversed-phase UPLC method was developed for determination and separation of aniline from the drug product. The drug and impurity are well separated by using a reversed phase (Reprosil Gold C18-XBD) column and mobile phase comprising of buffer pH 6.0 and acetonitrile in the ratio of 90:10 v/v. Other UPLC parameters which were optimised are flow rate, 0.5 mL/min; detection wavelength, 200 nm; column oven temperature, 50°C and injection volume 7 µL. Stability indicating capability was also established by forced degradation experiments. The method was validated as per ICH guideline. LOQ (limit of quantification) concentration (18 ng/mL) was found precise with RSD of less than 2%. In essence, the present study provides an improved low detection limit and lower run time for evaluation of pharmaceutical quality of mesalamine delayed-release formulation. Moreover, the developed method was also successfully applied for quantification of aniline in mesalamine delayed-release formulation. The same method can also be used for determination of aniline from drug substances.

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