title: Determination of bifonazole and identification of its photocatalytic degradation products using UPLC-MS/MS.
abstract: The main goal of the presented work was to investigate the effect of ZnO or/and TiO2on the stability of bifonazole in solutions under UVA irradiation. To this end, a simple and reproducible UPLC method for the determination of bifonazole in the presence of its photocatalytic degradation products was developed. Linearity was studied in the range of 0.0046-0.15 mg mL-1with a determination coefficient of 0.9996. Bifonazole underwent a photocatalytic degradation process under the experimental conditions used. Comparative studies showed that combination of TiO2/ZnO (1:1 w/w) was a more effective catalyst than TiO2or ZnO with a degradation rate of up to 67.57% after 24 h of irradiation. Further, kinetic analyses indicated that the photocatalytic degradation of bifonazole in the mixture of TiO2/ZnO can be described by a pseudo-first order reaction. Statistical comparison clearly indicated that the presence of TiO2/ZnO also affected the stability of bifonazole from a cream preparation after 15 h of UVA exposure (p < 0.05). Ten photodegradation products of bifonazole were identified for the first time and their plausible fragmentation pathways, derived from MS/MS data, were proposed. The main pathway in the photocatalytic transformation of bifonazole in the presence of ZnO or/and TiO2involves hydroxylation of the methanetriyl group and/or adjacent phenyl rings and cleavage of the imidazole moiety.
authors.affiliation: Department of Inorganic and Analytical Chemistry, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Agata
authors.identifier: http://orcid.org/0000-0001-9125-250X
authors.initials: A
authors.lastname: Kryczyk
authors.affiliation: Department of Medicinal Chemistry, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Paweł
authors.identifier: http://orcid.org/0000-0003-3594-1241
authors.initials: P
authors.lastname: Żmudzki
authors.affiliation: Department of Inorganic and Analytical Chemistry, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Urszula
authors.initials: U
authors.lastname: Hubicka
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007093:Imidazoles / Q000032:analysis* / Q000737:chemistry* / Q000528:radiation effects; D057230:Limit of Detection; D016014:Linear Models; D010782:Photolysis; D015203:Reproducibility of Results; D063465:Skin Cream / Q000737:chemistry; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D007093:Imidazoles; D014874:Water Pollutants, Chemical; C036596:bifonazole
keywords: TiO2; ZnO; bifonazole; kinetic evaluation; photocatalytic degradation studies; photostability