Photo-Degradation of Cypermethrin in Aqueous Solution Studied by HPLC-DAD

2013 ◽  
Vol 634-638 ◽  
pp. 1044-1048
Author(s):  
Yan Ru Liang ◽  
Zhen Bin Gong ◽  
Wen Quan Li
Keyword(s):  
Aqueous Solution ◽  
High Performance ◽  
Degradation Products ◽  
Degradation Process ◽  
Mass Spectrometric ◽  
Photochemical Degradation ◽  
Pseudo First Order Reaction ◽  
Photo Degradation ◽  
Mass Spectrometric Detector ◽  
Degradation Reaction

The photo-degradation process of cypermethrin in aqueous solution was studied using the laboratory-built photochemical degradation device and commercial high performance liquid chromatography (HPLC) with ultraviolet-visible absorbance detector and mass spectrometric detector. Spectrometric characteristics of cypermethrin and its main degradation products suggest that cypermethrin could be photo-degradated and converted into smaller molecular under ultraviolet irradiation. The photo-degradation reaction of cypermethrin in aqueous solution is approximately pseudo-first-order reaction. Light strength, pH and salinity have significant effects on the photo-degradaiton reaction of cypermethrin. Mass spectrometric results show that cypermethrin pesticide can be degraded into new and easily photochemical degrading products through the removal of chlorine.

Laboratory Simulation Study of Photo-Degradation Process of Fenvalerate in Aqueous Solution

2013 ◽  
Vol 312 ◽  
pp. 886-892
Author(s):  
Yan Ru Liang ◽  
Yu Yun Wen ◽  
Xiao Yan Hong ◽  
Zhen Bin Gong ◽  
Wen Quan Li
Keyword(s):  
Aqueous Solution ◽  
Reaction Rate ◽  
Organic Molecules ◽  
Spectral Characteristics ◽  
Degradation Process ◽  
Laboratory Simulation ◽  
Fluorescent Substance ◽  
Photo Degradation ◽  
Small Organic Molecules ◽  
Degradation Reaction

A laboratory-made the efficient photochemical degradation experimental device, combined with high performance liquid chromatography-tandem diode array detector device (DAD), fluorescence detector (FLD), mass spectrometer detector (MS), research fenvalerate its photo degradation. The structure of the spectral characteristics is the product, photo degradation reaction kinetics of degradation products, suggesting fenvalerate light chemical degradation process in an aqueous solution. The spectral characteristics of fenvalerate under ultraviolet light can be degraded into smaller organic molecules; maternal and main product have strong UV - visible absorption, fenvalerate are weakly fluorescent substance in the aqueous solution. The major products are strong fluorescent substance. Almost no effect The photo degradation kinetic data show fenvalerate photo degradation in an aqueous solution to approximate a reaction of the reaction; pesticide initial concentration, the pH value of the aqueous solution of pesticides photo degradation reaction rate; To accelerate the increase of salinity, light intensity fenvalerate in aqueous photo degradation reaction rate; significant influence of small organic molecules, with the type of small organic molecules.

Effect of Environmental Factors of Mannanase on Konjac Glucomannan Molecular Dimension

2011 ◽  
Vol 689 ◽  
pp. 308-314
Author(s):  
Xiao Yan Long ◽  
Xue Gang Luo ◽  
Ju Bai ◽  
Jia Feng Zhu
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Reaction Time ◽  
Environmental Factors ◽  
Weight Distribution ◽  
Degradation Process ◽  
Konjac Glucomannan ◽  
Molecular Dimension ◽  
Degradation Reaction ◽  
Theoretical Foundations

The environmental factors of mannanase konjac glucomannan (KGM) have been investigated in aqueous solution. Molecular weight (Mw) and molecular weight distribution (WMD) of the degraded KGM were measured by GPC. During the degradation process, the molecular weight of the enzymatic products decreases with reaction time, degradation reaction combining two reactions processed with different orders, while WMD broadens at first and then becomes narrow. The reduction of molecular dimension of KGM was lowered with temperature increase, but WMD increases. WMD was reduced with concentration of enzyme increase, but the reduction of molecular dimension of KGM was insignificant in the range of 2.0~6.5 u.mL-1of mannanase concentration. The results show that molecular dimension of KGM could be controlled by soft changes of reaction environment, dimension of KGM molecule could be decreased more than 100 times so as to obtain oligosaccharides, which offers the reference to reliable theoretical foundations and practical ground in exploiting KGM potential function and activity.

scholarly journals Ultraviolet-Photodiode Array and High-Performance Liquid Chromatographic/Mass Spectrometric Studies on Forced Degradation Behavior of Glibenclamide and Development of a Validated Stability-Indicating Method

2008 ◽  
Vol 91 (4) ◽  
pp. 709-719 ◽  
Author(s):  
Gulshan Bansal ◽  
Manjeet Singh ◽  
Kaur Chand Jindal ◽  
Saranjit Singh
Keyword(s):  
Degradation Product ◽  
High Performance ◽  
Limit Of Detection ◽  
Degradation Products ◽  
Mass Spectrometric ◽  
Forced Degradation ◽  
Degradation Behavior ◽  
Prolonged Heating ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic

Abstract A forced degradation study on glibenclamide was performed under conditions of hydrolysis, oxidation, dry heat, and photolysis and a high-performance column liquid chromatographic-ultraviolet (HPLC-UV) method was developed to study degradation behavior of the drug under the forced conditions. The degradation products formed under different forced conditions were characterized through isolation and subsequent infrared/nuclear magnetic resonance/mass spectral analyses, or through HPLC/mass spectrometric (HPLC/MS) studies. The drug degraded in 0.1 M HCl and water at 85C toamajor degradation product, 5-chloro-2-methoxy-N-2-(4-sulfamoylphenyl)ethyl]benzamide (III), and to a minor product, 1-cyclohexyl-3-[[4-(2-aminoethyl)-phenyl]sulfonyl]urea (IV). Upon prolonged heating in the acid, the minor product IV disappeared, resulting in formation of 5-chloro-2-methoxy-benzoic acid (II) and an unidentified product (I). Heating of the drug in 0.1 M NaOH at 85C yielded II and IV as the major products and I and III as the minor products. The drug and the degradation products formed under different conditions were optimally resolved on a C18 column using ammonium acetate buffer (0.025 M, pH 3.5)acetonitrile (45 + 55) mobile phase at a flow rate of 0.6 mL/min, with detection at 230 nm. The method was validated for linearity, precision, accuracy, and specificity. Limit of detection (LOD) and limit of quantitation (LOQ) values were also determined. The method could be successfully applied for simultaneous quantification of glibenclamide and the major product, III. The response of the method was linear in a narrow [0.410 g/mL, correlation coefficient (r2 = 0.9982] and a wide (0.4500 g/mL, r2 = 0.9993) concentration range for glibenclamide, and in the concentration range of 0.02550 g/mL (r2 = 0.9998) for III. The method proved to be precise and accurate for both glibenclamide and III. It was specific for the drug and also selective for each degradation product, and LOQ values for the drug were 0.1 and 0.4 g/mL, whereas those for III were 0.010 and 0.025 g/mL, respectively.

Validation of analytical methods: case study

2020 ◽  
Vol 86 (8) ◽  
pp. 72-79
Author(s):  
M. Yu. Medvedevskikh ◽  
M. P. Krasheninina ◽  
A. S. Sergeeva ◽  
V. B. Baranovskaya
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Analytical Methods ◽  
High Performance ◽  
Experimental Studies ◽  
Measurement Range ◽  
Mass Spectrometric ◽  
Residual Content ◽  
Mass Spectrometric Detector

The study continues the research previously published in the article «Validation of analytical methods: the international requirements» (Zavod. Lab. Diagn. Mater. 2018. Vol. 84. No. 12, pp. 25 – 31). We consider the procedure and the results of validation of the measurement procedure for determination of the residual content of enrofloxacin in food using high performance liquid chromatography with mass spectrometric detection. The program of experimental studies and calculation formulas necessary to assess the metrological characteristics of the method are presented. Validation included assessment of the detection limit, quantitation limit, decision limit, capability of enrofloxacin detection in food samples in accordance with GOST 32797–2014 «Food products, food raw materials. Method for the determination of the residual content of quinolones using high performance liquid chromatography with a mass spectrometric detector». The linearity of the calibration characteristic within the measurement range is demonstrated using the regression analysis procedure. The values of the accuracy indicators and the measurement range specified in GOST 32797–2014 were confirmed when the method was implemented in a testing laboratory.

A study of ofloxacin and levofloxacin photostability in aqueous solutions

10.20883/178 ◽  
2016 ◽  
Vol 85 (4) ◽  
pp. 238
Author(s):  
Anita Frąckowiak ◽  
Bartosz Kamiński ◽  
Bartosz Urbaniak ◽  
Paweł Dereziński ◽  
Agnieszka Klupczyńska ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
High Performance ◽  
Degradation Products ◽  
Mercury Vapor ◽  
Degradation Process ◽  
Hplc Method ◽  
Photodegradation Products ◽  
Kinetics Of Degradation ◽  
High Performance Capillary Electrophoresis ◽  
Kinetics Of

Introduction. The photostability is one of the most important properties of drugs. A comprehensive study of ofloxacin (OFX) and levofloxacin (LVX) photostability in aqueous solutions was performed. Ofloxacin is a chemotherapeutic agent belonging to the second generation fluoroquinolones and is a racemate of (R)-(+)-ofloxacin and (S)-(-)-ofloxacin (LVX).Material and Methods. Samples of OFX and LVX were subjected to stress conditions of UV irradiation using a mercury‑vapor lamp. The study involved development of enantioselective high‑performance liquid chromatography (HPLC) and high‑performance capillary electrophoresis (HPCE) methods for separation of OFX enantiomers and their degradation products. These methods were used to monitor the degradation process of OFX and LVX under irradiation and to determine the kinetics of degradation of these antibacterial agents. Moreover, the identification of photoproducts was also attempted. The structure of the main photoproducts was examined by mass spectrometry (MS).Results and Conclusions. Using HPLC method it was possible to observe two products of OFX degradation and only one for LVX, while using HPCE method eight products of OFX degradation and six of LVX were observed. Some of the photoproducts retain character of optically active compounds. The trend of the photodegradation of both tested compounds was described by autocatalytic reaction proceeding according to the Prout‑Tompkins model. Some of the products of the decomposition catalyze this reaction. The rate of degradation was similar for both enantiomers but t0.5 was slightly longer for LVX than OFX. Based on MS experiments the photodegradation products of the studied fluoroquinolones and possible pathways of UV induced decay were identified.

Study of degradation products and degradation pathways of sulfonated azo dyes under ultraviolet irradiation

2017 ◽  
Vol 89 (3) ◽  
pp. 322-334
Author(s):  
Jiangang Qu ◽  
Nannan Li ◽  
Chunmei Wang ◽  
Jinxin He
Keyword(s):  
Mass Spectrometry ◽  
Azo Dyes ◽  
Ultraviolet Irradiation ◽  
High Performance ◽  
Degradation Products ◽  
Inorganic Ions ◽  
Degradation Process ◽  
Gas Chromatography Mass Spectrometry ◽  
Ionization Mass ◽  
Degradation Pathways

Monitoring the light-induced decomposition course of azo dyes is essential to understand their degradation pathways and mechanisms. In this study, two model dyes are synthesized and used for stimulating the photodegradation processes of azo and hydrazone dyes, respectively. Their intermediates formed during initial and final fading processes are characterized by high-performance liquid chromatography-electrospray ionization-mass spectrometry, gas chromatography-mass spectrometry and ion chromatography. Results reveal that no dramatic differences are observed between the two dyes, although hydrazone dye would undergo a more complicated degradation process. Hydroxyl radicals are the dominant reactive species involved in the photodegradation of both model dyes under ultraviolet irradiation. In the initial steps, the intermediates are almost hydroxylated derivatives, while low-molecular-weight dicarboxylic acids and their hydroxylated and esterified derivatives, as well as non-volatile inorganic ions, are detected and evidenced in the final steps. Furthermore, photodegradation pathways and mechanisms for the two model dyes are proposed accordingly.

Sign in / Sign up

Export Citation Format

Share Document