scholarly journals Development of a Nanocluster-Based Platform for Determination of Sofosbuvir

2021 ◽  
Author(s):  
Zahra Karimzadeh ◽  
Abolghasem Jouyban ◽  
Elaheh Rahimpour
Keyword(s):  
Response Surface Methodology ◽  
Limit Of Detection ◽  
Copper Nitrate ◽  
Plasma Samples ◽  
Copper Nanoclusters ◽  
Good Repeatability ◽  
Direct Acting ◽  
Optimized Conditions ◽  
Linear Concentration

Background: Sofosbuvir is a potent direct-acting antivirus agent that has been listed as a promising medicine for the treatment of all genotypes of hepatitis C virus. As antiviral drugs could be metabolized to their associated compounds and toxicologically and pharmacologically interfere with the parent drugs, identifying the therapeutic range of drugs would be notable. Methods: In the current study, copper nanoclusters (Cu NCs) are synthesized during the reduction of copper nitrate with hydrazine hydrate in a protected media and used as a nanoprobe for the determination of sofosbuvir in plasma samples. Herein, synchronous fluorescence spectroscopy (SFS) is used for monitoring of fluorescence variation of nanoprobe owing to the excessive benefits compared with the traditional fluorescence. Results: SFS peak of Cu NCs has appeared at 355 nm with ∆λ=80 nm which is decreased in the presence of sofosbuvir. To optimize the reaction factors, a response surface methodology is used and in the optimized conditions, a linear concentration-response plot is obtained in a range of 0.05-6.0 µg mL−1 with a limit of detection of 0.0147 µg mL−1. Conclusion: The developed method also reveals good repeatability and selectivity for sofosbuvir in plasma samples.

Ultrasound-Assisted Dispersive Liquid–Liquid Microextraction and Capillary Electrophoretic Determination of Tramadol in Human Plasma

2020 ◽  
Vol 16 ◽  
Author(s):  
Paria Habibollahi ◽  
Azam Samadi ◽  
Alireza Garjani ◽  
Samad Shams Vahdati ◽  
Hamid-Reza Sargazi ◽  
...  
Keyword(s):  
Human Plasma ◽  
Limit Of Detection ◽  
Plasma Samples ◽  
Extraction Solvent ◽  
Human Plasma Samples ◽  
Good Repeatability ◽  
Ultrasound Assisted ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

BACKGROUND: Tramadol, (±)-trans-2-[(dimethylamino) methyl]-1-(3-methoxyphenyl) cyclohexanol, is a synthetic centrally acting analgesic used in the treatment of moderate to chronic pain. Tramadol like other narcotic drugs is used for the treatment of pain and also may be abused. Its overdose can cause adverse effects such as dizziness, vomiting, and nausea. The aim of this paper is to develop a sample preparation method for the determination of tramadol in human plasma samples followed by CE analysis. METHODS: Ultrasound assisted-dispersive liquid–liquid microextraction using binary mixed extractant solvent (chloroform and ethyl acetate) was used for extraction of one hundred microliters of tramadol spiked human plasma samples and in real human plasma samples obtained from the patients with abuse of tramadol. After evaporation the extractant solvent, the residue was reconstituted in 100 µL deionized water and subsequently analyzed by CE-UV. RESULTS: The developed method has remarkable characteristics including simplicity, good repeatability and appreciable accuracy. Under the best extraction conditions, low limit of detection at 7.0 µg per liter level with good linearity in the range of 0.02–10 µg mL‒1 was obtained. CONCLUSION: UA-DLLME using a binary mixed extraction solvent was established for the determination of tramadol in human plasma samples via CE method with UV-detection. In addition, the analysis of tramadol in some plasma samples of patients with abuse of tramadol indicated that the method has acceptable performance for determination of tramadol in plasma samples which indicate that the method is suitable for clinical applications.

scholarly journals DETERMINATION OF TRACE NITRITE AS 4-(4-NITROBENZENAZO)- 1-AMINONAPHTHALENE COMPLEX BY EXTRACTION-SPECTROPHOTOMETRY

2010 ◽  
Vol 9 (2) ◽  
pp. 254-260
Author(s):  
Choirul Amri ◽  
Dwi Siswanta ◽  
Mudasir Mudasir
Keyword(s):  
Detection Limit ◽  
Organic Solvents ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Limit Of Detection ◽  
Absorbance Unit ◽  
Extraction Spectrophotometry ◽  
Linear Concentration

A study of extraction-spectrophotometric method for the determination of trace nitrite as 4-(4-nitrobenzenazo)-1-aminonaphthalene complex using n-amylalcohol and chloroform as organic solvents has been done. Results of the study showed that extraction-spectrophotometric determination of nitrite using n-amylalcohol or chloroform was very sensitive and had low limit of detection. Extraction-spectrophotometric method of nitrite using n-amylalcohol gave range of linear concentration 0.000-0.054 mg/L NO2--N, detection limit of 2.09x10-4 mg/L NO2--N, and sensitivity of 34.514 ± 0.398 absorbance unit per mg/L of NO2--N. Meanwhile, extraction-spectrophotometric of nitrite using chloroform had range of linear concentration of 0.000-0.100 mg/L NO2--N, detection limit of 8.99x10-4 mg/L NO2--N, and sensitivity of 18.353 ± 0.456 absorbance unit per mg/L NO2--N.   Keywords: Nitrite Trace, 4-(4-Nitrobenzenazo)-1-Aminonaphthalene, Extraction-Spectrophotometry

scholarly journals Development of an Analytical Protocol for Determination of Cyanide in Human Biological Samples Based on Application of Ion Chromatography with Pulsed Amperometric Detection

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Ewa Jaszczak ◽  
Marek Ruman ◽  
Sylwia Narkowicz ◽  
Jacek Namieśnik ◽  
Żaneta Polkowska
Keyword(s):  
Ion Chromatography ◽  
Biological Samples ◽  
Amperometric Detection ◽  
Sample Pretreatment ◽  
Cyanide Ion ◽  
Pulsed Amperometric Detection ◽  
Analytical Protocol ◽  
Good Repeatability ◽  
Optimized Conditions

A simple and accurate ion chromatography (IC) method with pulsed amperometric detection (PAD) was proposed for the determination of cyanide ion in urine, sweat, and saliva samples. The sample pretreatment relies on alkaline digestion and application of Dionex OnGuard II H cartridge. Under the optimized conditions, the method showed good linearity in the range of 1–100 μg/L for urine, 5–100 μg/L for saliva, and 3–100 μg/L for sweat samples with determination coefficients (R)>0.992. Low detection limits (LODs) in the range of 1.8 μg/L, 5.1 μg/L, and 5.8 μg/L for urine, saliva, and sweat samples, respectively, and good repeatability (CV < 3%, n=3) were obtained. The proposed method has been successfully applied to the analysis of human biological samples.

scholarly journals  Determination of CLINDAMYCIN HCl in Capsules by New, Validated, Simple and Green Kinetic Spectrometric Method

2021 ◽  
Author(s):  
Shaza Affas ◽  
Amir Alhaj Sakur
Keyword(s):  
Initial Rate ◽  
Limit Of Detection ◽  
Reference Method ◽  
Fixed Time ◽  
Spectrometric Method ◽  
Iodide Ions ◽  
Kinetic Spectrophotometric ◽  
Optimized Conditions ◽  
Good Agreement

Abstract Background: simple, sensitive, free of organic solvents, kinetic spectrophotometric method has been developed for the determination of Clindamycin Hydrochloride, both in pure form and Capsules. Method used is based on reaction of Clindamycin with potassium iodide and potassium iodate in aqueous medium at (25 ±2 °c) to produce yellow colored tri iodide ions (I3-). the reaction is followed spectrophotometrically by measuring the absorbance at 350 nm wavelength during 40 minutes. Results: the effects of analytical parameters on reported kinetic methods were investigated. Under the optimized conditions, the initial rate and fixed time (at 10 min) methods were used for constructing the calibration graphs. The graphs were linear in concentration ranges 1-20 μg.ml-1 with limit of detection of 0.12 and 0.22 μg ml-1for the initial rate and fixed time methods, respectively. The results were satisfactory and the analytical performance for both methods was validated. Conclusion: The proposed methods have been applied to determine the components in capsules with an average recovery of 98.25% to 102.00% and the results are in good agreement with those found by the reference method.

scholarly journals Melamine Recognition: Molecularly Imprinted Polymer for Selective and Sensitive Determination of Melamine in Food Samples

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Mohadese Biabani ◽  
Azizollah Nezhadali ◽  
Ahmad Nakhaei ◽  
Hossein Nakhaei
Keyword(s):  
Limit Of Detection ◽  
Electrochemical Techniques ◽  
Food Samples ◽  
Quantitative Measurements ◽  
Sensitive Determination ◽  
Burman Design ◽  
Mip Sensor ◽  
Optimized Conditions ◽  
Plackett Burman Design

In this study, a sensitive and selective sensor is constructed to measure the melamine (MEL) using molecular imprinting polymer (MIP) technique. Chemical and electrochemical techniques are used to construct the MIP and quantitative measurements. The constructed sensor was modified with GO-Fe3O4@SiO2 nanocomposite. Screening and optimization of factors are done using statistical methods, including Plackett–Burman design (PBD) and central composite design (CCD). Under the optimized conditions, an MIP sensor showed a linear range from 5.0 × 10−7 to 1.0 × 10−5 M MEL concentration with a correlation coefficient (R2) of 0.9997. The limit of detection was obtained (0.028 µM) with a highly reproducible response (RSD 2.15%, n = 4). The electrochemical sensor showed good results for the determination of MEL in food samples.

scholarly journals Spectrofluorimetric determination of amlodipine in human plasma without derivatization

2012 ◽  
Vol 48 (4) ◽  
pp. 719-725 ◽  
Author(s):  
Yucel Kadioglu ◽  
Murat Ozturk
Keyword(s):  
Channel Blocker ◽  
Limit Of Detection ◽  
Plasma Samples ◽  
Experimental Conditions ◽  
Spectrofluorimetric Method ◽  
Relative Standard ◽  
Limit Of Quantitation ◽  
Spectrofluorimetric Determination ◽  
Better Than

A rapid and sensitive spectrofluorimetric method was developed for the determination of amlodipine (AD), a calcium channel blocker, in the plasma. The type of solvent, the wavelength range, and the range of AD concentration were selected to optimize the experimental conditions. The calibration curves were linear (r² >0.997) in the concentration range of 0.1-12.5 ppm of AD. The limit of quantitation and limit of detection values for the method for plasma samples were 0.1 ppm and 0.07 ppm, respectively. The precision calculated as the relative standard deviation was less than 3.5%, and the accuracy (relative error) was better than 5.5% (n=6). The method developed in this study can be directly and easily applied for the determination of AD in the plasma without derivatization in plasma.

scholarly journals Dispersed Conducting Polymer Nanocomposites with Glucose Oxidase and Gold Nanoparticles for the Design of Enzymatic Glucose Biosensors

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2173
Author(s):  
Natalija German ◽  
Almira Ramanaviciene ◽  
Arunas Ramanavicius
Keyword(s):  
Glucose Oxidase ◽  
Conducting Polymer ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Serum Samples ◽  
Glucose Determination ◽  
Constant Potential ◽  
Good Repeatability ◽  
Graphite Rod

Biosensors for the determination of glucose concentration have a great significance in clinical diagnosis, and in the food and pharmaceutics industries. In this research, short-chain polyaniline (PANI) and polypyrrole (Ppy)-based nanocomposites with glucose oxidase (GOx) and 6 nm diameter AuNPs (AuNPs(6 nm)) were deposited on the graphite rod (GR) electrode followed by the immobilization of GOx. Optimal conditions for the modification of GR electrodes by conducting polymer-based nanocomposites and GOx were elaborated. The electrodes were investigated by cyclic voltammetry and constant potential amperometry in the presence of the redox mediator phenazine methosulfate (PMS). The improved enzymatic biosensors based on GR/PANI-AuNPs(6 nm)-GOx/GOx and GR/Ppy-AuNPs(6 nm)-GOx/GOx electrodes were characterized by high sensitivity (65.4 and 55.4 μA mM−1 cm−2), low limit of detection (0.070 and 0.071 mmol L−1), wide linear range (up to 16.5 mmol L−1), good repeatability (RSD 4.67 and 5.89%), and appropriate stability (half-life period (τ1/2) was 22 and 17 days, respectively). The excellent anti-interference ability to ascorbic and uric acids and successful practical application for glucose determination in serum samples was presented for GR/PANI-AuNPs(6 nm)-GOx/GOx electrode.

scholarly journals Aptamer-Based Fluorescence Quenching Approach for Detection of Aflatoxin M1 in Milk

2021 ◽  
Vol 9 ◽  
Author(s):  
Qinqin Qiao ◽  
Xiaodong Guo ◽  
Fang Wen ◽  
Lu Chen ◽  
Qingbiao Xu ◽  
...  
Keyword(s):  
Dairy Products ◽  
Limit Of Detection ◽  
Aflatoxin M1 ◽  
Fluorescence Signal ◽  
Simple Method ◽  
Global Concern ◽  
Structure Switching ◽  
Optimized Conditions ◽  
Milk And Dairy Products

Aflatoxin M1 (AFM1), one of the most toxic mycotoxins, is a feed and food contaminant of global concern. In this study, we developed a fast and simple method for detection of AFM1 based on a structure-switching signaling aptamer. This aptasensor is based on the change in fluorescence signal due to formation of an AFM1/aptamer complex. To generate the aptasensor, the specific aptamer was modified with FAM (carboxyfluorescein), and their complementary DNAs (cDNA) were modified with a carboxytetramethylrhodamine (TAMRA) quenching group. In the absence of AFM1, the aptamers were hybridized with cDNA, resulting in quenching of the aptamer fluorescence due to the proximity of the aptamer’s fluorophore to the quenching group on the cDNA. On the other hand, in the presence of AFM1, a structural switch in the aptamer was induced by formation of an AFM1/aptamer complex. Changes in the structure of the aptamer led to the release of the cDNA, causing the generation of a fluorescence signal. Thus, AFM1 concentrations could be quantitatively monitored based on the changes in fluorescences. Under optimized conditions, this assay exhibited a linear response to AFM1 in the range of 1–100 ng/mL and a limit of detection of 0.5 ng/mL was calculated. This proposed aptasensor was applied to milk samples spiked with a dilution series of AFM1, yielding satisfactory recoveries from 93.4 to 101.3%. These results demonstrated that this detection technique could be useful for high-throughput and quantitative determination of mycotoxin levels in milk and dairy products.

scholarly journals DEVELOPMENT OF A TECHNIQUE FOR THE MASS-SPECTROMETRIC DETERMINATION OF GONADOTROPIN-RELEASING HORMONE AND ITS ANALOGS FOR DOPING CONTROL

2017 ◽  
Vol 12 (2) ◽  
pp. 81-99
Author(s):  
K. M. Shestakova ◽  
G. A. Dudko ◽  
M. A. Dikunets
Keyword(s):  
Matrix Effects ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Internal Standard ◽  
Ion Source ◽  
Gonadotropin Releasing Hormone ◽  
Selected Reaction Monitoring ◽  
Releasing Hormone ◽  
Optimized Conditions

In the present study, a rapid, sensitive, and selective method for determination of several synthetic analogues of gonadotropin-releasing hormone in human urine by solid-phase extraction and ultraperformance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) was developed. Various parameters affecting sample preparation, LC separation, and MS/MS detection were investigated, and optimized conditions were identified. The UPLC-MS/MS system was equipped with an electrospray ion source operating in positive ion mode with selected reaction monitoring. Leuprolide-13С6 was used as internal standard for analytes quantitative assessment. The proposed method was validated considering the parameters specificity, linearity (0.1-10 ng/ml), recovery (52-98%), limit of detection (0.1 ng/ml), matrix effects and stability.

scholarly journals Indirect detection of 5-hydroxytryptamine and tyramine by using tris(2,2’-bipyridyl)ruthenium-graphene modified electrode coupled with capillary electrophoresis

2019 ◽  
Vol 10 (4) ◽  
pp. 336-344
Author(s):  
Zi Wei Zhao ◽  
Fan Lin Li ◽  
Ming Su
Keyword(s):  
Capillary Electrophoresis ◽  
Sulfonic Acid ◽  
Electrostatic Interactions ◽  
Limit Of Detection ◽  
Indirect Detection ◽  
Plasma Samples ◽  
Functionalized Graphene ◽  
Quenching Mechanism ◽  
Highly Sensitive

A highly sensitive and stable solid-state electrochemiluminescence (ECL) sensor was developed based on tris(2,2’-bipyridyl)ruthenium(II) (Ru(bpy)32+) integrating with 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) functionalized graphene. Ru(bpy)32+ is incorporated with the ABTS functionalized graphene based on not only the π-π stacking but also electrostatic interactions. Coupled with capillary electrophoresis (CE), this ECL sensor was used to detect tyramine and 5-hydroxytryptamine (5-HT) based on their quenching effects for the Ru(bpy)32+/tripropylamine (TPA) system. The quenching mechanism was illustrated and the conditions for CE separation and ECL detection were optimized. Based on an S/N = 3, the limit of detection (LOD) for tyramine and 5-HT were 0.1 μM and 0.02 μM, respectively. The applicability of the proposed method was further illustrated in the determination of tyramine and 5-HT in human plasma samples from small intestine carcinoid patients.

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