Monitoring the degradation of tetracycline by ozone in aqueous medium via atmospheric pressure ionization mass spectrometry

Dalmázio, Ilza; Almeida, Mariana O.; Augusti, Rodinei; Alves, Tânia Maria de Almeida

doi:10.1016/j.jasms.2006.12.001

Cited by 160 publications

(60 citation statements)

References 49 publications

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“…30 Recent examples have shown that ESI-MS, in conjunction with ESI-MS/MS, can be successfully applied to monitor a number of processes, including the environmentally-relevant ones, furnishing novel and significant information about them. [31][32][33][34][35][36][37][38][39][40][41] In this work, ESI(-)-MS (electrospray ionization mass spectrometry in the negative ion mode), in conjunction with ultraviolet-visible spectrophotometry (UV-Vis) and total organic carbon (TOC) techniques, were employed to monitor the reductive degradation of four prototype food dyes: Amaranth (1), Sunset Yellow (2), Red 40 (3) and Brilliant Blue (4) (Figure 1). The reactions were Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Degradation of food dyes by zero-valent metals exposed to ultrasonic irradiation in water medium: optimization and electrospray ionization mass spectrometry monitoring

Pavanelli¹,

Bispo²,

Nascentes³

et al. 2011

J. Braz. Chem. Soc.

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A degradação redutiva de quatro corantes típicos (Azul Brilhante, Amaranto, Amarelo Crepúsculo e Vermelho 40), largamente empregados pela indústria alimentícia, por metais de valência zero (Fe e Sn), sob irradiação ultrassônica (US) em meio aquoso ácido (pH 3,0), foi estudada. As reações foram monitoradas por ESI(-)-MS (espectrometria de massas com ionização electrospray no modo negativo), além de espectrofotometria UV-Vis e carbono orgânico total (TOC). A influência de parâmetros preponderantes (tempo de exposição à radiação ultrassônica e massa do metal) nas taxas de degradação foi seguramente estabelecida por meio da construção de planejamentos fatoriais e superfícies de resposta. Deste modo, observou-se que, sob as condições experimentais otimizadas, ferro metálico (Fe) degradou eficientemente todos os corantes (com taxas de degradação superiores a 90% após 30 min de reação), enquanto que estanho metálico (Sn) apresentou um desempenho notavelmente inferior. As baixas taxas de mineralização obtidas foram consequência, provavelmente, do caráter essencialmente redutivo de tais processos. Baseado nos resultados do monitoramento por ESI(-)MS, uma rota de degradação plausível para o corante Azul Brilhante em meio aquoso, pelo sistema Fe/US, foi proposta e envolve, como etapas iniciais, a hidrogenação da ligação dupla exocíclica carbono-carbono, seguida pela inserção de hidreto no grupamento imino da molécula.The reductive degradation of four prototype dyes largely employed by the food industry (Brilliant Blue, Amaranth, Sunset Yellow and Red 40), by zero-valent metals (Fe and Sn) under ultrasonic irradiation in acidic aqueous solution (pH 3.0), was studied. The reactions were monitored by direct infusion ESI(-)-MS (electrospray ionization mass spectrometry in the negative ion mode) as well as by UV-Vis and total organic carbon (TOC). The influence of major parameters (time of exposure to ultrasonic irradiation and mass of metal) on the degradation rates was firmly established by means of factorial design and surface response approaches. Hence, it was noticed that, under the optimized experimental conditions, metallic iron (Fe) was able to efficiently degrade all the dyes (with rates higher than 90% after 30 min reaction time), whereas metallic tin (Sn) exhibited a noticeably lower performance. Low mineralization rates were achieved probably due to the essentially reductive character of such process. Based on the results from the ESI(-)-MS monitoring, a plausible degradation route for the Brilliant Blue dye in aqueous medium by the Fe/US system was proposed. Hence, this route involves, as initial pathways, the hydrogenation of the exocyclic carbon-carbon double bond of the dye followed by the insertion of hydride at its imino moiety. Keywords: electrospray ionization mass spectrometry, monitoring, food dyes, zero-valent metals IntroductionColor is by far the most important sensorial property of foods. In this way, dyes have been widely used to accentuate their original colors, or to provide different ones.While bei...

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Section: Introductionmentioning

confidence: 99%

Degradation of food dyes by zero-valent metals exposed to ultrasonic irradiation in water medium: optimization and electrospray ionization mass spectrometry monitoring

Pavanelli¹,

Bispo²,

Nascentes³

et al. 2011

J. Braz. Chem. Soc.

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“…Pharmaceuticals and personal care products (PPCPs) are now recognized as a new class of emerging pollutants and have been the subject of increasing concern and scientific interest [1,2]. Several kinds of drugs, such as antibiotics, hormones, preservatives and anesthetics, have been identified in surface water, groundwater, sewage water, and drinking water, of which antibiotics are of special concern due to their extensive use in human and veterinary medicine [3,4].…”

Section: Introductionmentioning

confidence: 99%

Photodegradation of tetracycline and formation of reactive oxygen species in aqueous tetracycline solution under simulated sunlight irradiation

Chen

et al. 2008

Journal of Photochemistry and Photobiology A: Chemistry

252

100

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The photochemical kinetics and mechanism of the antibiotic compound tetracycline (TC) was investigated in aqueous solution under simulated sunlight irradiation. The study of the electron spin resonance revealed that the singlet oxygen ( 1 O 2 ) was generated and the formation rate decreased with increasing pH in illuminated TC solution. Also, it was found that the H 2 O 2 was produced and increased with increasing pH under the simulated sunlight irradiation. The results verified that TC could be sunlight excited and induced the formation of reactive oxygen species. Moreover, the contributions of oxidation reaction to photodegradation of TC were clarified by the role of different radical scavengers. The kinetic model elucidated the involvement of TC photoinduced singlet oxygen on the photodegradation of TC. It was verified that the photodegradation of TC was predominantly attributed to direct photolysis. The quantum yields of direct photolysis increases with increasing pH in the range of 6.0-9.0, varying from 3.4 × 10 −4 to 1.1 × 10 −2 . The indirect photolysis of TC was carried out in the presence of nitrate, bicarbonate, ferric ions and humic acid (HA), respectively. The results verified that the photodegradation of tetracycline was not obviously affected by these photosensitizers except ferric ions, indicating that the direct photolysis of TC was predominant process.

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“…[27][28][29] Electrospray ionization mass spectrometry (ESI-MS), because of its appealing and unique attributes, has rapidly becoming an alternative approach suitably employed to a direct monitoring of a increasing number of relevant environmental processes. [30][31][32][33][34][35][36][37][38][39][40] In these inquiries, the information provided by the MS (the m/z values of the ionic species) and MS/MS data (the fragmentation profiles of a given mass-selected ion) are meticulously evaluated aiming to propose chemical structures of products (and in some cases transient intermediates) likely formed in the condensed phase. 41 The identification of by-products arising from oxidative treatments, which can be more risky than the own precursors indeed, 42 is an important point that must be taken into consideration for the evaluation of the overall performance of a given process.…”

Section: Introductionmentioning

confidence: 99%

Ozonation of ethinylestradiol in aqueous-methanolic solution: direct monitoring by electrospray ionization mass spectrometry

Vieira¹,

Nascentes²,

Augusti³

2010

J. Braz. Chem. Soc.

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A ozonólise do etinilestradiol (1), um hormônio sintético esteroidal, numa solução de água/metanol foi investigada. Análises por HPLC-UV revelaram que o hormônio foi completamente consumido, tanto em pH 5 quanto 8, após um tempo reacional de 20 min. O monitoramento por espectrometria de massas com ionização electrospray no modo negativo (ESI(-)-MS) revelou o contínuo consumo de 1 (detectado em sua forma desprotonada, [1 -H] -, de m/z 295), concomitantemente com o aparecimento de produtos de oxidação. Estruturas químicas foram propostas para tais produtos com base nos dados de MS (valores de m/z) e MS/MS (padrões de fragmentação dos ânions). Estes dados, em associação com conhecimento sobre a reatividade de moléculas orgânicas frente ao ozônio em solução aquosa, foram avaliados e uma rota reacional inédita para a ozonização do etinilestradiol foi sugerida. Assim, como primeira etapa nesta sequência reacional propôs-se uma adição 1,3-dipolar do ozônio sobre o anel fenólico de 1 para gerar o produto di-hidroxilado 2 (detectado como [2 -H] -de m/z 311). A perda de acetileno como o único canal de dissociação de [2 -H] -confirmou que a hidroxilação ocorreu no anel fenólico e não na porção acetilênica de 1. Oxidações subsequentes foram propostas para explicar a formação de outros produtos, todos eles contendo o grupo funcional COOH (como verificado pela dissociação das respectivas moléculas desprotonadas através da perda característica de CO 2 ). Os dados de ESI(-)-MS também revelaram diferenças notáveis entre as reações conduzidas em pH 5 e 8, i.e., em meios levemente ácido e básico, respectivamente.The ozonolysis of ethinylestradiol (1), a synthetic steroidal estrogen, in an aqueous-methanolic solution was investigated. HPLC-UV analyses revealed that 1 was completely consumed after a 20 min reaction time either at pH 5 or 8. ESI(-)-MS (electrospray ionization mass spectrometry in the negative ion mode) monitoring also revealed the continuous consumption of 1 (detected as [1 -H] -of m/z 295) concomitantly with the emergence of oxidation products. Chemical structures were proposed for these products based on the data of MS and MS/MS (the m/z values and fragmentation profiles of the anionic specie, respectively). These data, in conjunction with the well-established knowledge about the reactivity of organic molecules toward ozone in aqueous solution, were evaluated and an unprecedented reaction route for the ozonation of 1 could thus be suggested. Hence, the first step in this reaction sequence was ascribed to involve a 1,3-dipolar cycloaddition of ozone at the phenolic ring of 1 yielding the di-hydroxylated product 2 (detected as [2 -H] -of m/z 311). The loss of acetylene as the unique dissociation channel for [2 -H] -thus confirmed that such hydroxylation occurred at the phenolic ring rather than the acetylenic moiety of 1. Subsequent oxidations were proposed to be the origin of a number of other products, all of them bearing the COOH functionally (this was verified by the characteristic loss of CO 2 during the...

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Monitoring the degradation of tetracycline by ozone in aqueous medium via atmospheric pressure ionization mass spectrometry

Cited by 160 publications

References 49 publications

Degradation of food dyes by zero-valent metals exposed to ultrasonic irradiation in water medium: optimization and electrospray ionization mass spectrometry monitoring

Degradation of food dyes by zero-valent metals exposed to ultrasonic irradiation in water medium: optimization and electrospray ionization mass spectrometry monitoring

Photodegradation of tetracycline and formation of reactive oxygen species in aqueous tetracycline solution under simulated sunlight irradiation

Ozonation of ethinylestradiol in aqueous-methanolic solution: direct monitoring by electrospray ionization mass spectrometry

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