Photoinduced Isomerization of Lycopene and Application to Tomato Cultivation

The present study aimed to investigate if growth conditions have an impact on the isomeric composition of lycopene in tomatoes. First a model system for photoinduced isomerization was established. Tomato extracts were irradiated with a halogen lamp, whose wavelength spectrum is close to the spectrum of daylight and thus mimics field-grown cultivation. Different optical filters were interposed between lamp and samples to simulate greenhouse conditions. 5-<i>cis</i>-Lycopene was formed preferentially while the concentration of 7-<i>cis</i>-lycopene decreased in field-grown model systems. The change of isomerization in greenhouse model systems led to a significantly different ratio. Consequently 5-<i>cis</i>- and 7-<i>cis</i>-lycopene were identified as potent markers for the differentiation of various lighting conditions during cultivation. This result was verified in biological samples. Authentic field-grown tomatoes (<i>var. Lycopersicon esculentum Mill. var. commune L. H. Bailey “Harzfeuer”</i>) showed a significantly higher content of 5-<i>cis</i>-lycopene 5.90 ± 0.45% compared to tomatoes of the same variety grown under electric lighting 4.11 ± 0.10%. Additionally, the ratio of 7-<i>cis</i>-lycopene was significantly lower under field-grown conditions

Photochemically Induced Bound Residue Formation of Carbamazepine with Dissolved Organic Matter

More than 400 new nitrogen containing products were detected upon experimental sunlight photolysis of the pharmaceutical carbamazepine (CBZ) in the presence of dissolved organic matter (DOM) by Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). These products were presumably formed through covalent binding of CBZ phototransformation products with DOM molecules. About 50% of these newly formed bound residues contained one nitrogen atom and had a molecular mass between 375 and 525 Da, which was 150 to 200 Da higher than for an average DOM molecule. In addition, a previously unknown CBZ phototransformation product, 3-quinolinecarboxylic acid (3-QCA), was identified by liquid chromatography high resolution tandem mass spectrometry (LC-HRMS/MS). 3-QCA was likely formed through oxidative ring cleavage and subsequent decarboxylation of acridine, a well-known phototransformation product of CBZ. Collision induced dissociation experiments and Kendrick mass defect analyses corroborated that about 160 of the new products were formed via covalent binding of 3-QCA with DOM molecules of above-average O/C and H/C ratios. Experiments at lower CBZ concentration suggested that the importance of bound residue formation increases with increasing DOM/CBZ ratios. Photochemically induced bound residue formation of polar contaminants with DOM in the aqueous phase is thus a disregarded pathway along which contaminants can be transformed in the environment. The method presented here offers a new possibility to study the formation of bound residues, which may be of relevance also for other transformation processes in natural waters where radical intermediates are generated