scholarly journals Online Monitoring of Electrochemical Degradation of Paracetamol through a Biomimetic Sensor

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Mariana Calora Quintino de Oliveira ◽  
Marcos Roberto de Vasconcelos Lanza ◽  
José Luis Paz Jara ◽  
Maria Del Pilar Taboada Sotomayor
Keyword(s):  
Liquid Chromatography ◽  
Flow Injection Analysis ◽  
Online Monitoring ◽  
Degradation Products ◽  
Process Efficiency ◽  
Carbon Electrode ◽  
Electrochemical Degradation ◽  
First Time ◽  
Line Analysis ◽  
Biomimetic Sensor

This paper reports, for the first time, the online monitoring to the electrochemical degradation of the paracetamol using a biomimetic sensor coupled to a Flow Injection Analysis (FIA) system. The electrochemical degradation of the drug was carried out in aqueous medium using a flow-by reactor with a DSA anode. The process efficiency was monitored at real time by the biomimetic sensor constructed by modifying a glassy carbon electrode with a Nafion membrane doped with iron tetrapyridinoporphyrazine (FeTPyPz). Simultaneously, we carried out off-line analysis by liquid chromatography (HPLC) during the experiments in order to validate the proposed system. In addition, to investigate the degradation products of the paracetamol electrolysis, we used the techniques of UPLC/MS and GC/MS.

Analysis of herbicide atrazine and its degradation products in cereals by ultra-performance liquid chromatography-mass spectrometry

2016 ◽  
Vol 8 (17) ◽  
pp. 3599-3604 ◽  
Author(s):  
Shuxuan Liang ◽  
Xinfeng Dong ◽  
Ming Su ◽  
Hanwen Sun
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Degradation Products ◽  
Ultra Performance Liquid Chromatography ◽  
Liquid Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Herbicide Atrazine ◽  
First Time

A novel ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) method was developed for the first time for the determination of herbicide atrazine (ATR) and its principal metabolites namely desisopropylatrazine (DIA), desethylatrazine (DEA) and hydroxyatrazine (HA) in cereals.

scholarly journals Investigation of forced and total degradation products of amlodipine besylate by liquid chromatography and liquid chromatography-mass spectrometry

2014 ◽  
Vol 20 (2) ◽  
pp. 295-304 ◽  
Author(s):  
Zora Stoiljkovic ◽  
Milka Jadranin ◽  
Svetlana Djuric ◽  
Slobodan Petrovic ◽  
Avramov Ivic ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Degradation Products ◽  
Chemical Oxidation ◽  
Reversed Phase ◽  
Mass Spectrometry Analysis ◽  
Molecular Formula ◽  
Electrochemical Degradation ◽  
Amlodipine Besylate ◽  
Spectrometry Analysis

An isocratic, reversed-phase liquid chromatographic method was applied for the investigation of the degradation products of amlodipine besylate under the stressed conditions in solution. Amlodipine besylate stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation and photodegradation as well as to the electrochemical degradation by cyclic voltammetry in 0.05 mol/L NaHCO3 on gold electrode. The total degradation of amlodipine besylate was achieved in 5 mol/L NaOH at 80?C for 6 h and the compound with molecular formula C15H16NOCl was identified as a main degradation product. Under acidic (5 mol/L HCl at 80?C for 6 h) stress conditions 75.2% of amlodipine besylate degradation was recorded. Oxidative degradation in the solution of 3% H2O2-methanol 80:20 at 80?C for 6 h showed that amlodipine besylate degraded to 80.1%. After 14 days of expose in photostability chamber amlodipine besylate solution showed degradation of 32.2%. In electrochemical degradation after 9 hours of cyclization the beginning of amlodipine oxidation was shifted for 200 mV to more negative potentials, with the degradation of 66.5%. Mass spectrometry analysis confirmed the presence of dehydro amlodipine derivate with molecular formula C20H23N2O5Cl in oxidative and acidic conditions while in electrochemical degradation was detected in traces.

scholarly journals Enantioselective Monitoring of Biodegradation of Ketamine and Its Metabolite Norketamine by Liquid Chromatography

Chemosensors ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 242
Author(s):  
Ariana Pérez-Pereira ◽  
Alexandra Maia ◽  
Virgínia Gonçalves ◽  
Cláudia Ribeiro ◽  
Maria Elizabeth Tiritan
Keyword(s):  
Liquid Chromatography ◽  
Wastewater Treatment Plants ◽  
Degradation Products ◽  
Sewage Treatment ◽  
Epidemiological Studies ◽  
Aquatic Environments ◽  
Limit Of Quantification ◽  
Chiral Compounds ◽  
Array Detection ◽  
First Time

Ketamine (K) and its main metabolite, norketamine (NK), are chiral compounds that have been found in effluents from wastewater treatment plants (WWTPs) and aquatic environments. Little is known about their enantioselective biodegradation during sewage treatment; however, this information is pivotal for risk assessment, the evaluation of WWTP performance and wastewater epidemiological studies. The aim of this study was to investigate the biodegradation pattern of the enantiomers of K by activated sludge (AS) from a WWTP. For that, an enantioselective liquid chromatography with diode array detection (LC-DAD) method was developed and validated to quantify the enantiomers of K and NK. Both K and NK enantiomers were separated, in the same chromatographic run, using a Lux® 3 µm cellulose-4 analytical column under isocratic elution mode. The method was demonstrated to be linear (r2 > 0.99) and precise (<11.3%). Accuracy ranged between 85.9 and 113.6% and recovery ranged between 50.1 and 86.9%. The limit of quantification was 1.25 µg/mL for the enantiomers of NK and 2.5 µg/mL for K. The method was applied to monitor the biodegradation assay of the enantiomers of K by AS for 14 days. K was poorly biodegraded, less than 15% for both enantiomers, and enantioselectivity in the biodegradation was not observed. The metabolite NK and other possible degradation products were not detected. This work reports, for the first time, the behavior of both enantiomers of K in biodegradation studies.

The Influence of Some Factors on Spirolactone Stability in Solution

2008 ◽  
Vol 59 (7) ◽  
Author(s):  
Daniela Lucia Muntean ◽  
Silvia Imre ◽  
Cosmina Voda
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Uv Irradiation ◽  
High Performance ◽  
Degradation Products ◽  
Simultaneous Action ◽  
Ethanolic Solution ◽  
Degradation Processes ◽  
Stable Solutions ◽  
Preformulation Study

The influence of some factors on spironolactone stability in solution was studied, by applying high-performance liquid chromatography, as a part of a pharmaceutical preformulation study in order to obtain a spironolactone solution for alopecia treatment. Solutions of 1 mg/ml spironolactone in aqueous ethanolic solution 1 : 1 and in 20 mM cyclodextrines solutions (b-, hydroxi-b- and methyl-b-cyclodextrine) was used, maintained at 8 and 22 �C, protected from light and after UV irradiation at 254 nm. The main degradation products were 7a-thiospirolactone and canrenone. The most stable solutions were the alcoholic ones and with methyl-beta-cyclodextrine, but the simultaneous action of temperature and UV irradiation allowed degradation processes after one hour of exposure, more aggressive in the presence of methyl-beta-cyclodextrine. In conclusion, for alopecia treatment with spironolactone a 1 mg/mL ethanolic solution could be used and it is recommendable the protection of treated zone.

scholarly journals Characterization and Study on Fragmentation Pathways of a Novel Nerve Agent, ‘Novichok (A234)’, in Aqueous Solution by Liquid Chromatography–Tandem Mass Spectrometry

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1059
Author(s):  
Jin Young Lee ◽  
Kyoung Chan Lim ◽  
Hyun Suk Kim
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solution ◽  
Liquid Chromatography ◽  
Degradation Products ◽  
Aqueous Sample ◽  
Tandem Mass ◽  
Aqueous Samples ◽  
Fragmentation Pathways ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

As a first step toward studying the properties of Novichok (ethyl (1-(diethylamino)ethylidene)phosphoramidofluoridate (A234)), we investigated its degradation products and fragmentation pathways in aqueous solution at different pH levels by liquid chromatography–tandem mass spectrometry. A234 was synthesized in our laboratory and characterized by nuclear magnetic resonance spectroscopy. Three sets of aqueous samples were prepared at different pH levels. A stock solution of A234 was prepared in acetonitrile at a concentration of 1 mg/mL and stored at −20 °C until use. Aqueous samples (0.1 mg/mL) were prepared by diluting the stock solution with deionized water. The acidic aqueous sample (pH = 3.5) and basic aqueous sample (pH = 9.4) were prepared using 0.01 M acetic acid and 0.01 M potassium carbonate, respectively. The analysis of the fragmentation patterns and degradation pathways of A234 showed that the same degradation products were formed at all pH levels. However, the hydrolysis rate of A234 was fastest under acidic conditions. In all three conditions, the fragmentation pattern and the major degradation product of A234 were determined. This information will be applicable to studies regarding the decontamination of Novichok and the trace analysis of its degradation products in various environmental matrices.

Identification, Characterization, and Quantification of Impurities of Safinamide Mesilate: Process-Related Impurities and Degradation Products

2017 ◽  
Vol 100 (4) ◽  
pp. 1029-1037 ◽  
Author(s):  
Liang Zou ◽  
Lili Sun ◽  
Hui Zhang ◽  
Wenkai Hui ◽  
Qiaogen Zou ◽  
...  
Keyword(s):  
Degradation Products ◽  
Hplc Method ◽  
Formation Mechanisms ◽  
Stability Indicating ◽  
Related Impurities ◽  
Related Substances ◽  
Water Ph ◽  
Bulk Drug ◽  
First Time

Abstract The characterization of process-related impurities and degradation products of safinamide mesilate (SAFM) in bulk drug and a stability-indicating HPLC method for the separation and quantification of all the impurities were investigated. Four process-related impurities (Imp-B, Imp-C, Imp-D, and Imp-E) were found in the SAFM bulk drug. Five degradation products (Imp-A, Imp-C, Imp-D, Imp-E, and Imp-F) were observed in SAFM under oxidative conditions. Imp-C, Imp-D, and Imp-E were also degradation products and process-related impurities. Remarkably, one new compound, identified as (S)-2-[4-(3-fluoro-benzyloxy) benzamido] propanamide (i.e., Imp-D), is being reported here as an impurity for the first time. Furthermore, the structures of the aforementioned impurities were characterized and confirmed via IR, NMR, and MS techniques, and the most probable formation mechanisms of all impurities proposed according to the synthesis route. Optimum separation was achieved on an Inertsil ODS-3 column (250 × 4.6 mm, 5 μm), using 0.1% formic acid in water (pH adjusted to 5.0) and acetonitrile as the mobile phase in gradient mode. The proposed method was found to be stability-indicating, precise, linear, accurate, sensitive, and robust for the quantitation of SAFM and its process-related substances, including its degradation products.

Sign in / Sign up

Export Citation Format

Share Document