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.

scholarly journals Isolation and Structure Determination of Echinochrome A Oxidative Degradation Products

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4778
Author(s):  
Natalia P. Mishchenko ◽  
Elena A. Vasileva ◽  
Andrey V. Gerasimenko ◽  
Valeriya P. Grigorchuk ◽  
Pavel S. Dmitrenok ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Degradation Products ◽  
Lethal Dose ◽  
Oxidative Degradation ◽  
Degradation Process ◽  
Oxidation Products ◽  
Chemical Mechanism ◽  
Ionization Mass ◽  
Echinochrome A ◽  
Esi Ms

Echinochrome A (Ech A, 1) is one of the main pigments of several sea urchin species and is registered in the Russian pharmacopeia as an active drug substance (Histochrome®), used in the fields of cardiology and ophthalmology. In this study, Ech A degradation products formed during oxidation by O2 in air-equilibrated aqueous solutions were identified, isolated, and structurally characterized. An HPLC method coupled with diode-array detection (DAD) and mass spectrometry (MS) was developed and validated to monitor the Ech A degradation process and identify the appearing compounds. Five primary oxidation products were detected and their structures were proposed on the basis of high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) as 7-ethyl-2,2,3,3,5,7,8-heptahydroxy-2,3-dihydro-1,4-naphthoquinone (2), 6-ethyl-5,7,8-trihydroxy-1,2,3,4-tetrahydronaphthalene-1,2,3,4-tetraone (3), 2,3-epoxy-7-ethyl-2,3-dihydro-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone (4), 2,3,4,5,7-pentahydroxy-6-ethylinden-1-one (5), and 2,2,4,5,7-pentahydroxy-6-ethylindane-1,3-dione (6). Three novel oxidation products were isolated, and NMR and HR-ESI-MS methods were used to establish their structures as 4-ethyl-3,5,6-trihydroxy-2-oxalobenzoic acid (7), 4-ethyl-2-formyl-3,5,6-trihydroxybenzoic acid (8), and 4-ethyl-2,3,5-trihydroxybenzoic acid (9). The known compound 3-ethyl-2,5-dihydroxy-1,4-benzoquinone (10) was isolated along with products 7–9. Compound 7 turned out to be unstable; its anhydro derivative 11 was obtained in two crystal forms, the structure of which was elucidated using X-ray crystallography as 7-ethyl-5,6-dihydroxy-2,3-dioxo-2,3-dihydrobenzofuran-4-carboxylic acid and named echinolactone. The chemical mechanism of Ech A oxidative degradation is proposed. The in silico toxicity of Ech A and its degradation products 2 and 7–10 were predicted using the ProTox-II webserver. The predicted median lethal dose (LD50) value for product 2 was 221 mg/kg, and, for products 7–10, it appeared to be much lower (≥2000 mg/kg). For Ech A, the predicted toxicity and mutagenicity differed from our experimental data.

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.

Environmental Friendly Degradation of Atrazine by Ozone and Identification of Main Degradation Products

2014 ◽  
Vol 1001 ◽  
pp. 52-57
Author(s):  
Marián Šudý ◽  
Karol Balog ◽  
Maroš Soldán
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Degradation Products ◽  
Degradation Process ◽  
Gas Chromatography Mass Spectrometry ◽  
Oh Radicals ◽  
Environmental Friendly ◽  
Chromatography Mass Spectrometry ◽  
Atrazine Degradation

The present study investigates the degradation of atrazine (2-chloro-4-(ethylamino)-6-isopropylamino-s-triazine) by ozone and OH radicals during ozonization with the identification of the main degradation products after ozonation. The identification of main degradation products during atrazine degradation process was conducted by gas chromatography–mass spectrometry (GC–MS).

scholarly journals Brain/blood ratios of methadone and ABCB1 polymorphisms in methadone-related deaths

2021 ◽  
Vol 135 (2) ◽  
pp. 473-482
Author(s):  
S. Iwersen-Bergmann ◽  
S. Plattner ◽  
S. Hischke ◽  
A. Müller ◽  
H. Andresen-Streichert ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Performance ◽  
Efflux Pump ◽  
Venous Blood ◽  
Reversed Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Ionization Mass ◽  
Nucleotide Polymorphisms ◽  
Gene Encoding ◽  
The Brain

AbstractMethadone is an opioid that often leads to fatalities. Interpretation of toxicological findings can be challenging if no further information about the case history is available. The aims of this study were (1) to determine whether brain/blood ratios can assist in the interpretation of methadone findings in fatalities; (2) to examine whether polymorphisms in the gene encoding the P-glycoprotein (also known as multidrug resistance protein 1 (MDR1) or ATP-binding cassette sub-family B member 1 (ABCB1)), which functions as a multispecific efflux pump in the blood–brain barrier, affect brain/blood ratios of methadone. Femoral venous blood and brain tissue (medulla oblongata and cerebellum) from 107 methadone-related deaths were analysed for methadone by gas chromatography-mass spectrometry. In addition, all the samples were genotyped for three common ABCB1 single nucleotide polymorphisms (SNPs rs1045642, rs1128503, and rs2032582) using ion-pair reversed-phase high-performance liquid chromatography-electrospray ionization mass spectrometry (ICEMS). In nearly all cases, methadone concentrations were higher in the brain than in the blood. Inter-individual brain/blood ratios varied (0.6–11.6); the mean ratio was 2.85 (standard deviation 1.83, median 2.35). Moreover, significant differences in mean brain/blood ratios were detected among the synonymous genotypes of rs1045642 in ABCB1 (p = 0.001). Cases with the T/T genotype had significantly higher brain/blood ratios than cases with the other genotypes (T/T vs. T/C difference (d) = 1.54, 95% CI [1.14, 2.05], p = 0.002; T/T vs. C/C d = 1.60, 95% CI [1.13, 2.29], p = 0.004). Our results suggest that the rs1045642 polymorphisms in ABCB1 may affect methadone concentrations in the brain and its site of action and may be an additional factor influencing methadone toxicity.

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