scholarly journals Photocatalytic Degradation of Trifluralin, Clodinafop-Propargyl, and 1,2-Dichloro-4-Nitrobenzene As Determined by Gas Chromatography Coupled with Mass Spectrometry

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Niyaz A. Mir ◽  
A. Khan ◽  
M. Muneer ◽  
S. Vijayalakhsmi
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Photocatalytic Degradation ◽  
Degradation Mechanism ◽  
Gas Chromatography Mass Spectrometry ◽  
Ionization Mass ◽  
Water Medium ◽  
Fragmentation Pattern ◽  
Chemical Structures ◽  
Clodinafop Propargyl

Phototransformation is considered one of the most key factors affecting the fate of pesticides. Therefore, our study focused on photocatalytic degradation of three selected pesticide derivatives: trifluralin (1), clodinafop-propargyl (2), and 1,2-dichloro-4-nitrobenzene (3). The degradation was carried out in acetonitrile/water medium in the presence of titanium dioxide (TiO2) under continuous purging of atmospheric air. The course of degradation was followed by thin-layer chromatography and gas chromatography-mass spectrometry techniques. Electron ionization mass spectrometry was used to identify the degradation species. GC-MS analysis indicates the formation of several intermediate products which have been characterized on the basis of molecular ion, mass fragmentation pattern, and comparison with NIST library. The photocatalytic degradation of pesticides of different chemical structures manifested distinctly different degradation mechanism. The major routes for the degradation of pesticides were found to be (a) dealkylation, dehalogenation, and decarboxylation, (b) hydroxylation, (c) oxidation of side chain, if present, (d) isomerization and cyclization, (e) cleavage of alkoxy bond, and (f) reduction of triple bond to double bond and nitro group to amino.

scholarly journals Analytical Variables Affecting Analysis of F2-Isoprostanes and F4-Neuroprostanes in Human Cerebrospinal Fluid by Gas Chromatography/Mass Spectrometry

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Hsiu-Chuan Yen ◽  
Hsing-Ju Wei ◽  
Ting-Wei Chen
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Cerebrospinal Fluid ◽  
Chemical Ionization ◽  
Negative Ion ◽  
Gas Chromatography Mass Spectrometry ◽  
Ionization Mass ◽  
Negative Ion Chemical Ionization ◽  
Gold Marker

F2-isoprostanes (F2-IsoPs) are a gold marker of lipid peroxidationin vivo, whereas F4-neuroprostanes (F4-NPs) measured in cerebrospinal fluid (CSF) or brain tissue selectively indicate neuronal oxidative damage. Gas chromatography/negative-ion chemical-ionization mass spectrometry (GC/NICI-MS) is the most sensitive and robust method for quantifying these compounds, which is essential for CSF samples because abundance of these compounds in CSF is very low. The present study revealed potential interferences on the analysis of F2-IsoPs and F4-NPs in CSF by GC/NICI-MS due to the use of improper analytical methods that have been employed in the literature. First, simultaneous quantification of F2-IsoPs and F4-NPs in CSF samples processed for F4-NPs analysis could cause poor chromatographic separation and falsely higher F2-IsoPs values for CSF samples with high levels of F2-IsoPs and F4-NPs. Second, retention of unknown substances in GC columns from CSF samples during F4-NPs analysis and from plasma samples during F2-IsoPs analysis might interfere with F4-NPs analysis of subsequent runs, which could be solved by holding columns at a high temperature for a period of time after data acquisition. Therefore, these special issues should be taken into consideration when performing analysis of F2-IsoPs and F4-NPs in CSF to avoid misleading results.

scholarly journals Metabolic Analysis of Vigna unguiculata Sprouts Exposed to Different Light-Emitting Diodes

2018 ◽  
Vol 13 (10) ◽  
pp. 1934578X1801301 ◽  
Author(s):  
Hyeon Ji Yeo ◽  
Chang Ha Park ◽  
Kyoung Bok Lee ◽  
Jae Kwang Kim ◽  
Jong Seok Park ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Vigna Unguiculata ◽  
High Performance ◽  
Light Emitting Diodes ◽  
Gas Chromatography Mass Spectrometry ◽  
Ionization Mass ◽  
Total Carotenoids ◽  
Light Emitting ◽  
Tof Ms

In order to determine the effect of light-emitting diodes (LEDs) on plant metabolism, the present study examined the primary and secondary metabolite profiles of Vigna unguiculata L. Walp. sprouts that were exposed to red, blue, white, or a combination of red and blue LEDs using high-performance liquid chromatography (HPLC), electrospray ionization-mass spectrometry (ESI-MS), gas chromatography-mass spectrometry (GC-MS), and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). A total of 39 hydrophilic compounds were identified and quantitated using GC-TOF-MS, and six phenylpropanoids and six carotenoids were quantified using HPLC. The plants grown under blue LED light contained the highest level of total carotenoids (253.72 ± 17.27 μg/g) and phenylpropanoids (2600.51 ± 4.90 μg/g). Thus, the current study provides a new approach for enhancing the carotenoid and phenylpropanoid production of V. unguiculata.

Confirmatory Method for Sulfamethazine Residues in Cattle and Swine Tissues, Using Gas Chromatography-Chemical Ionization Mass Spectrometry

1984 ◽  
Vol 67 (1) ◽  
pp. 142-144
Author(s):  
Steven J Stout ◽  
William A Steller ◽  
Arthur J Manuel ◽  
Manfred O Poeppel ◽  
Andrian R Dacunha
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Chemical Ionization ◽  
Negative Ion ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Gas Chromatography Mass Spectrometry ◽  
Ionization Mass ◽  
Fragment Ions ◽  
Positive Ion

Abstract A gas chromatographic (GC) method has been reported for the determination of sulfamethazine residues in cattle and swine tissues. The extracts from this procedure were found to be directly amenable to examination by gas chromatography–mass spectrometry (GC-MS), allowing positive confirmation of an apparent residue of sulfamethazine. Chemical ionization mass spectrometry (CIMS) was chosen as the MS technique because it generated an ion indicative of intact sulfamethazine and fragment ions indicative of the amine functionality and sulfanil moiety. Positive ion (PI) chemical ionization mass spectrometry was adequate by itself for a confirmatory technique. Negative ion (NI) chemical ionization mass spectrometry alone could not be used for the confirmatory analysis of sulfamethazine, but it did offer a means to check the quantitative data from the positive ion analyses and provided complementary confirmatory data. Satisfactory recoveries were obtained for sulfamethazine in swine and cattle tissues at the tolerance level of 0.1 ppm. Apparent sulfamethazine residues in control tissues were less than 0.01 ppm.

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