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Stéphane Bouchonnet - One of the best experts on this subject based on the ideXlab platform.
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ultraviolet degradation of Procymidone structural characterization by gas chromatography coupled with mass spectrometry and potential toxicity of photoproducts using in silico tests
Rapid Communications in Mass Spectrometry, 2013Co-Authors: Ahmad Rifai, Yasmine Souissi, Christophe Genty, Carine Clavaguéra, Sophie Bourcier, Farouk Jaber, Stéphane BouchonnetAbstract:RATIONALE Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of Procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS Aqueous solutions of Procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of Procymidone. CONCLUSIONS 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than Procymidone itself considering the QSAR-predicted rat LD50.
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Ultraviolet degradation of Procymidone--structural characterization by gas chromatography coupled with mass spectrometry and potential toxicity of photoproducts using in silico tests.
Rapid Communications in Mass Spectrometry, 2013Co-Authors: Ahmad Rifai, Yasmine Souissi, Christophe Genty, Carine Clavaguéra, Sophie Bourcier, Farouk Jaber, Stéphane BouchonnetAbstract:RATIONALE: Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of Procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS: Aqueous solutions of Procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS: Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of Procymidone. CONCLUSIONS: 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than Procymidone itself considering the QSAR-predicted rat LD50. Copyright © 2013 John Wiley & Sons, Ltd
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Ultraviolet degradation of Procymidone – structural characterization by gas chromatography coupled with mass spectrometry and potential toxicity of photoproducts using in silico tests
Rapid communications in mass spectrometry : RCM, 2013Co-Authors: Ahmad Rifai, Yasmine Souissi, Christophe Genty, Carine Clavaguéra, Sophie Bourcier, Farouk Jaber, Stéphane BouchonnetAbstract:RATIONALE Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of Procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS Aqueous solutions of Procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of Procymidone. CONCLUSIONS 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than Procymidone itself considering the QSAR-predicted rat LD50.
Ahmad Rifai - One of the best experts on this subject based on the ideXlab platform.
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ultraviolet degradation of Procymidone structural characterization by gas chromatography coupled with mass spectrometry and potential toxicity of photoproducts using in silico tests
Rapid Communications in Mass Spectrometry, 2013Co-Authors: Ahmad Rifai, Yasmine Souissi, Christophe Genty, Carine Clavaguéra, Sophie Bourcier, Farouk Jaber, Stéphane BouchonnetAbstract:RATIONALE Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of Procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS Aqueous solutions of Procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of Procymidone. CONCLUSIONS 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than Procymidone itself considering the QSAR-predicted rat LD50.
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Ultraviolet degradation of Procymidone--structural characterization by gas chromatography coupled with mass spectrometry and potential toxicity of photoproducts using in silico tests.
Rapid Communications in Mass Spectrometry, 2013Co-Authors: Ahmad Rifai, Yasmine Souissi, Christophe Genty, Carine Clavaguéra, Sophie Bourcier, Farouk Jaber, Stéphane BouchonnetAbstract:RATIONALE: Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of Procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS: Aqueous solutions of Procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS: Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of Procymidone. CONCLUSIONS: 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than Procymidone itself considering the QSAR-predicted rat LD50. Copyright © 2013 John Wiley & Sons, Ltd
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Ultraviolet degradation of Procymidone – structural characterization by gas chromatography coupled with mass spectrometry and potential toxicity of photoproducts using in silico tests
Rapid communications in mass spectrometry : RCM, 2013Co-Authors: Ahmad Rifai, Yasmine Souissi, Christophe Genty, Carine Clavaguéra, Sophie Bourcier, Farouk Jaber, Stéphane BouchonnetAbstract:RATIONALE Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of Procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS Aqueous solutions of Procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of Procymidone. CONCLUSIONS 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than Procymidone itself considering the QSAR-predicted rat LD50.
Laura Marabini - One of the best experts on this subject based on the ideXlab platform.
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Estrogenic effect of Procymidone through activation of MAPK in MCF-7 breast carcinoma cell line.
Life sciences, 2005Co-Authors: Sonia Radice, Enzo Chiesara, Silvia Frigerio, R. Fumagalli, Daniela Parolaro, Tiziana Rubino, Laura MarabiniAbstract:Abstract Procymidone modifies sexual differentiation in vitro and induces estrogenic activity in primary cultured rainbow trout hepatocytes, as shown by an increase in the contents of vitellogenin and heat shock proteins. Since this dicarboximide fungicide is found in human tissues, it was considered of interest to investigate its ability to induce endocrine damage in the MCF-7 human cell line. The mechanism of this estrogenic action was also evaluated. Procymidone 100 μM stimulated cell growth from day 3 up to day 12 and raised the level of pS2 on day 3. Although Procymidone does not bind the estrogen receptor (ER), the antiestrogen ICI 182780 inhibited its effect on cell growth and pS2 content, suggesting that the ER is involved indirectly in these effects. In exploring the mechanism of ER indirect activation we found that the antibody against c-Neu receptor (9G6) did not modify Procymidone's effects on cell growth and pS2 expression. Thus, Procymidone does not bind the c-Neu membrane receptor, excluding this indirect ER activation pathway. We also found that Procymidone induced mitogen-activated protein kinase (MAPK) at 15 and 30 min, and that PD 98059, a MAPK (Erk1/2) inhibitor, prevented Procymidone's effects on cell growth and pS2, indicating that MAPK activation is responsible for Procymidone ER activation. The production of reactive oxygen species (ROS) with these times and elimination of the phenomenon by α-tocopherol (α-T), a ROS scavenger, is proof that oxygen free-radical production is at the basis of the MAPK activation by Procymidone.
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Estrogenic activity of Procymidone in rainbow trout (Oncorhynchus mykiss) hepatocytes: a possible mechanism of action.
Chemico-biological interactions, 2004Co-Authors: Sonia Radice, Enzo Chiesara, Silvia Frigerio, R. Fumagalli, Michela Ferraris, Laura MarabiniAbstract:Abstract It is known that Procymidone modifies sexual differentiation in vivo and in vitro, and that it induces vitellogenin (Vtg) synthesis in primary cultured rainbow trout hepatocytes. The aim of this study was to evaluate the mechanism underlying this latter in vitro estrogenic action. The cells were treated for 24 h with Procymidone 150 μM (with 17β-estradiol [E2] 20 μM as a positive control) combined with an estrogen receptor (ER) antagonist (tamoxifen 20 μM or ICI 182,780 1 μM) or, given the drug toxic action on the production of reactive oxygen species (ROS), a free radical scavenger (α-tocopherol 30 μM). The results from ELISA experiments provided evidence that Procymidone Vtg-induction is inhibited by ER antagonists and by α-tocopherol suggesting that both ER and ROS are involved in this effect. The ROS detection revealed that the treatment with α-tocopherol and tamoxifen completely prevented ROS induction by Procymidone, that was not inhibited by ICI 182,780. In exploring the mechanism mediating these events and its timing, we found that Procymidone induced mitogen-activated protein kinase (MAPK) at 30 and 60 min, and that this effect was blocked by co-treatment with α-tocopherol. In summary, the results of the study clearly support the idea that the estrogenic activity of Procymidone in primary cultured trout hepatocytes is mediated by ROS production, and that this activity is similar to that of the ligand-independent ER activation involving MAPK.
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Estrogenic activity of Procymidone in primary cultured rainbow trout hepatocytes (Oncorhynchus mykiss).
Toxicology in vitro : an international journal published in association with BIBRA, 2002Co-Authors: Sonia Radice, Laura Marabini, Michela Ferraris, Enzo ChiesaraAbstract:Abstract It has been shown that Procymidone, a dicarboximide fungicide, alters sexual differentiation in vivo and in vitro. The aim of this study was to evaluate the estrogenic activity of this fungicide using the synthesis of vitellogenin (Vtg) in rainbow trout hepatocyte as a biological marker. The cells were treated for 24 h with Procymidone 150 μ m , using 17β-estradiol 20 μ m as a positive control. The doses were chosen on the basis of cell viability (Neutral Red and MTT tests) and solubility. The results show that Procymidone leads to a qualitative and quantitative increase in Vtg synthesis. In Western immonoblots, the 170 and 30 kDa bands, which respectively correspond to the monomeric form of Vtg and posvitine, were brighter in cells treated with Procymidone and 17β-estradiol than those corresponding to the negative controls (cells treated for 24 h with DMSO 0.1% alone); ELISA showed that the cells treated with the fungicide and 17β-estradiol had a 48 and 76%, respectively, higher Vtg concentration than the negative controls ( P
Christophe Genty - One of the best experts on this subject based on the ideXlab platform.
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ultraviolet degradation of Procymidone structural characterization by gas chromatography coupled with mass spectrometry and potential toxicity of photoproducts using in silico tests
Rapid Communications in Mass Spectrometry, 2013Co-Authors: Ahmad Rifai, Yasmine Souissi, Christophe Genty, Carine Clavaguéra, Sophie Bourcier, Farouk Jaber, Stéphane BouchonnetAbstract:RATIONALE Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of Procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS Aqueous solutions of Procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of Procymidone. CONCLUSIONS 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than Procymidone itself considering the QSAR-predicted rat LD50.
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Ultraviolet degradation of Procymidone--structural characterization by gas chromatography coupled with mass spectrometry and potential toxicity of photoproducts using in silico tests.
Rapid Communications in Mass Spectrometry, 2013Co-Authors: Ahmad Rifai, Yasmine Souissi, Christophe Genty, Carine Clavaguéra, Sophie Bourcier, Farouk Jaber, Stéphane BouchonnetAbstract:RATIONALE: Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of Procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS: Aqueous solutions of Procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS: Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of Procymidone. CONCLUSIONS: 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than Procymidone itself considering the QSAR-predicted rat LD50. Copyright © 2013 John Wiley & Sons, Ltd
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Ultraviolet degradation of Procymidone – structural characterization by gas chromatography coupled with mass spectrometry and potential toxicity of photoproducts using in silico tests
Rapid communications in mass spectrometry : RCM, 2013Co-Authors: Ahmad Rifai, Yasmine Souissi, Christophe Genty, Carine Clavaguéra, Sophie Bourcier, Farouk Jaber, Stéphane BouchonnetAbstract:RATIONALE Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of Procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS Aqueous solutions of Procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of Procymidone. CONCLUSIONS 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than Procymidone itself considering the QSAR-predicted rat LD50.
Carine Clavaguéra - One of the best experts on this subject based on the ideXlab platform.
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ultraviolet degradation of Procymidone structural characterization by gas chromatography coupled with mass spectrometry and potential toxicity of photoproducts using in silico tests
Rapid Communications in Mass Spectrometry, 2013Co-Authors: Ahmad Rifai, Yasmine Souissi, Christophe Genty, Carine Clavaguéra, Sophie Bourcier, Farouk Jaber, Stéphane BouchonnetAbstract:RATIONALE Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of Procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS Aqueous solutions of Procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of Procymidone. CONCLUSIONS 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than Procymidone itself considering the QSAR-predicted rat LD50.
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Ultraviolet degradation of Procymidone--structural characterization by gas chromatography coupled with mass spectrometry and potential toxicity of photoproducts using in silico tests.
Rapid Communications in Mass Spectrometry, 2013Co-Authors: Ahmad Rifai, Yasmine Souissi, Christophe Genty, Carine Clavaguéra, Sophie Bourcier, Farouk Jaber, Stéphane BouchonnetAbstract:RATIONALE: Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of Procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS: Aqueous solutions of Procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS: Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of Procymidone. CONCLUSIONS: 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than Procymidone itself considering the QSAR-predicted rat LD50. Copyright © 2013 John Wiley & Sons, Ltd
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Ultraviolet degradation of Procymidone – structural characterization by gas chromatography coupled with mass spectrometry and potential toxicity of photoproducts using in silico tests
Rapid communications in mass spectrometry : RCM, 2013Co-Authors: Ahmad Rifai, Yasmine Souissi, Christophe Genty, Carine Clavaguéra, Sophie Bourcier, Farouk Jaber, Stéphane BouchonnetAbstract:RATIONALE Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of Procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS Aqueous solutions of Procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of Procymidone. CONCLUSIONS 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than Procymidone itself considering the QSAR-predicted rat LD50.