scholarly journals Rapid Surface Sensitivity and Selectivity Determination of New Materials Based on CdS, ZnS

2016 ◽  
Vol 152 ◽  
pp. 634-638 ◽  
Author(s):  
I.A. Kirovskaya ◽  
E.V. Mironova ◽  
A.A. Grigan ◽  
S.N. Pogodin ◽  
K.S. Zhansakova
Keyword(s):  
New Materials ◽  
Surface Sensitivity ◽  
Sensitivity And Selectivity

Simultaneous Determination of Alogliptin, Linagliptin, Saxagliptin, and Sitagliptin in Bulk Drug and Formulation by UPLC Q-TOF-MS

2020 ◽  
Vol 17 (1) ◽  
pp. 95-105
Author(s):  
Ramji Rathod ◽  
Faraat Ali ◽  
Amrish Chandra ◽  
Robin Kumar ◽  
Meenakshi Dahiya ◽  
...  
Keyword(s):  
Internal Standard ◽  
Gradient Elution ◽  
Ultra Performance Liquid Chromatography ◽  
Pharmaceutical Dosage Forms ◽  
Sensitivity And Selectivity ◽  
The Mean ◽  
Bulk Drug ◽  
Positive Ion ◽  
Higher Sensitivity

Background: A simple and sensitive Ultra Performance Liquid Chromatography-Mass Spectrometry method was developed and validated to measure the concentrations of Alogliptin (ALO), Linagliptin (LIN), Saxagliptin (SAX), and Sitagliptin (SIT) using Pioglitazone (PIO) as an internal standard. Methods: Chromatographic separation of six gliptins was achieved on a C-18 column (100×2.1 mm, 2.7 μm) using a mobile phase consisting of formic acid in water, 0.1%v/v: acetonitrile in gradient elution. Electrospray ionization (ESI) source was operated in the positive ion mode. Targeted MS/MS mode on a QTOF MS was used to quantify the drug utilizing the transitions of 340.1(m/z), 473.2 (m/z), 316.2 (m/z), 408.1 (m/z), and 357.1 (m/z) for ALO, LIN, SAX, SIT and PIO respectively. Results: As per ICH Q2R1 guidelines, a detailed validation of the method was carried out and the standard curves were found to be linear over the concentration ranges of 1516.0-4548.1 ng mL-1, 519.8- 1559.4 ng mL-1, 1531.4-4594.3 ng mL-1and 1519.6-4558.8 ng mL-1 for ALO, LIN, SAX and SIT respectively. Precision and accuracy results were within the acceptable limits. The mean recovery was found to be 98.8 _ 0.76 % (GEM), 102.2 _ 1.59 % (LIN), 95.3 _ 2.74 % (SAX) and 99.2 _ 1.75 % (SIT) respectively. Conclusions: The optimized validated UPLC QTOF-MS/MS method offered the advantage of shorter analytical times and higher sensitivity and selectivity. The optimized method is suitable for application in quantitative analysis of pharmaceutical dosage forms for QC laboratory.

Recent Advances in Electrochemical Determination of Pesticides

2021 ◽  
Vol 21 (12) ◽  
pp. 5795-5811
Author(s):  
Milan Z. Momčilović ◽  
Jelena S. Milićević ◽  
Marjan S. Ranđelović
Keyword(s):  
Electrochemical Sensors ◽  
Work Force ◽  
Electrochemical Determination ◽  
Human Consumption ◽  
Agricultural Practice ◽  
Carbon Paste ◽  
Boron Doped Diamond ◽  
Voltammetric Detection ◽  
Sensitivity And Selectivity

Widespread usage of pesticides in agricultural practice caused their residues to appear in water and food products intended for human consumption. The potential toxicity of these resources has raised awareness about pesticide tracking in the environment. Development of reliable electrochemical sensors for the on-site determination of pesticide concentrations is envisioned as an alternative to conventional chromatographic methods which are robust, expensive and require skilled work force. Modification of the working electrode surface can result in enhanced electrochemical response towards selected pesticide making such electrode convenient sensor for facile and efficient determination of pesticides in low concentrations. New generation of nanomaterials is applied in electrode modification in order to improve its sensitivity and selectivity. The present review summarizes significant advances in voltammetric detection of pesticides for the period of the past five years. The major focus of this review is set to the types of carbon and oxide based materials, metal nanoparticles, composites and other materials employed to upgrade standard electrode configurations such as glassy carbon and carbon paste electrodes, boron doped diamond electrodes, screen printed and film electrodes, metal and amalgam, and other kinds of electrodes.

X-ray photoemission studies of the interaction of metals and metal ions with DNA

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Esha Mishra ◽  
Subrata Majumder ◽  
Shikha Varma ◽  
Peter A. Dowben
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Conformational Changes ◽  
Photoelectron Spectroscopy ◽  
X Ray ◽  
Surface Sensitivity ◽  
Metal Interaction ◽  
The Status ◽  
Sensitivity And Selectivity ◽  
Insight Into

Abstract X-ray Photoelectron Spectroscopy (XPS) has been used to study the interactions of heavy metal ions with DNA with some success. Surface sensitivity and selectivity of XPS are advantageous for identifying and characterizing the chemical and elemental structure of the DNA to metal interaction. This review summarizes the status of what amounts to a large part of the photoemission investigations of biomolecule interactions with metals and offers insight into the mechanism for heavy metal-bio interface interactions. Specifically, it is seen that metal interaction with DNA results in conformational changes in the DNA structure.

Microsized Graphite Sensors for Potentiometric Determination of Cyclobenzaprine Hydrochloride in Pure Powder, Tablets, and Plasma

2011 ◽  
Vol 94 (6) ◽  
pp. 1807-1814 ◽  
Author(s):  
Nesrin K Ramadan ◽  
Hala E Zaazaa ◽  
Hanan A Merey
Keyword(s):  
Polyvinyl Chloride ◽  
International Union ◽  
Electroactive Material ◽  
Significant Difference ◽  
Intact Drug ◽  
Sensitivity And Selectivity ◽  
Ph Range ◽  
The U.S ◽  
Chloride Matrix

Abstract Two cyclobenzaprine hydrochloride (CZ) microsized graphite selective sensors were investigated with dibutylsebacate as a plasticizer in a polymeric matrix of carboxylated polyvinyl chloride (PVC-COOH) in the case of sensor 1, based on the interaction between the drug and the dissociated COOH groups in the PVC-COOH. Sensor 2 was based on the interaction between the drug and ammonium reineckate, which acted as anionic electroactive material in the presence of polyvinyl chloride matrix. The two sensors were constructed by using 2-hydroxy propyl β-cyclodextrin as an ionophore, which has a significant influence on increasing the membrane sensitivity and selectivity of both sensors. Fast and stable Nernstian responses of 1 × 10–5–1 × 10–2 and 1 × 10m–4–1 × 10–2 M for the two sensors, respectively, with slopes of 58.6 and 55.5 mV/decade, respectively, over the pH range 2–4 were obtained. The proposed method displayed useful analytical characteristics for determination of CZ in its pure powder form with average recoveries 99.95 ± 0.23 and 99.61 ± 0.34% for sensors 1 and 2, respectively, and in plasma with good recoveries. The sensors were also used to determine the intact drug in the presence of its degradate and, thus, could be used as stability-indicating methods. The obtained results by the proposed methods were statistically analyzed and compared with those obtained by the U.S. Pharmacopeia method; no significant difference for either accuracy or precision was observed. Results obtained with the two electrodes revealed their performance characteristics, which were evaluated according to International Union of Pure and Applied Chemistry recommendations.

scholarly journals Portable smartphone-integrated paper sensors for fluorescence detection of As(III) in groundwater

2020 ◽  
Vol 7 (12) ◽  
pp. 201500
Author(s):  
Sha Liu ◽  
Yong Li ◽  
Chao Yang ◽  
Liqiang Lu ◽  
Yulun Nie ◽  
...  
Keyword(s):  
Environmental Problem ◽  
Visual Detection ◽  
High Sensitivity ◽  
Integration System ◽  
Detection Range ◽  
Sensitivity And Selectivity ◽  
Toxic Metalloid ◽  
Interfering Ions ◽  
Cu Nanoclusters

Arsenic contamination in groundwater is a supreme environmental problem, and levels of this toxic metalloid must be strictly monitored by a portable, sensitive and selective analytical device. Herein, a new system of smartphone-integrated paper sensors with Cu nanoclusters was established for the effective detection of As(III) in groundwater. For the integration system, the fluorescence emissive peak of Cu nanoclusters at 600 nm decreased gradually with increasing As(III) addition. Meanwhile, the fluorescence colour also changed from orange to colourless, and the detection limit was determined as 2.93 nM (0.22 ppb) in a wide detection range. The interfering ions also cannot influence the detection selectivity of As(III). Furthermore, the portable paper sensors based on Cu nanoclusters were fabricated for visual detection of As(III) in groundwater. The quantitative determination of As(III) in natural groundwater has also been accomplished with the aid of a common smartphone. Our work has provided a portable and on-site detection technique toward As(III) in groundwater with high sensitivity and selectivity.

scholarly journals What are the Main Sensor Methods for Quantifying Pesticides in Agricultural Activities? A Review

Molecules ◽  
2019 ◽  
Vol 24 (14) ◽  
pp. 2659 ◽  
Author(s):  
Roy Zamora-Sequeira ◽  
Ricardo Starbird-Pérez ◽  
Oscar Rojas-Carillo ◽  
Seiling Vargas-Villalobos
Keyword(s):  
Detection Limit ◽  
Crop Production ◽  
Fruits And Vegetables ◽  
Extended Period ◽  
Pesticide Use ◽  
General Description ◽  
Agricultural Activities ◽  
Agricultural Pesticides ◽  
Sensitivity And Selectivity

In recent years, there has been an increase in pesticide use to improve crop production due to the growth of agricultural activities. Consequently, various pesticides have been present in the environment for an extended period of time. This review presents a general description of recent advances in the development of methods for the quantification of pesticides used in agricultural activities. Current advances focus on improving sensitivity and selectivity through the use of nanomaterials in both sensor assemblies and new biosensors. In this study, we summarize the electrochemical, optical, nano-colorimetric, piezoelectric, chemo-luminescent and fluorescent techniques related to the determination of agricultural pesticides. A brief description of each method and its applications, detection limit, purpose—which is to efficiently determine pesticides—cost and precision are considered. The main crops that are assessed in this study are bananas, although other fruits and vegetables contaminated with pesticides are also mentioned. While many studies have assessed biosensors for the determination of pesticides, the research in this area needs to be expanded to allow for a balance between agricultural activities and environmental protection.

Boosting theoretical zeolitic framework generation for the determination of new materials structures using GPU programming

2011 ◽  
Vol 13 (10) ◽  
pp. 4674 ◽  
Author(s):  
Laurent A. Baumes ◽  
Frederic Kruger ◽  
Santiago Jimenez ◽  
Pierre Collet ◽  
Avelino Corma
Keyword(s):  
Gpu Programming ◽  
New Materials ◽  
Zeolitic Framework
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