De novo formation of phthalimide from ubiquitous phthalic acid derivatives during the drying process of tea (Camellia sinensis) and selected herbal infusions.

It is well documented that under some circumstances phthalimide, a known degradation product of the fungicide folpet, can be formed as an artifact during gas chromatographic analysis. This fact explains one phthalimide source, but does not explain a great number of positive findings in the group of dried plant commodities obtained with an artifact-free analysis. Therefore, in the framework of this study, herbal and tea plants were grown in a glasshouse under the best possible protection against external environmental influences and ensuring the exclusion of the use of folpet. It was demonstrated that relevant amounts of phthalimide are formed during the drying process as part of the routine production of tea and herbals and in the absence of folpet. In this context, the presence of the widespread environmental chemical phthalic anhydride and its impact was investigated. We conclude that phthalimide is no reliable indicator for the active use of folpet.

A method for the quantification of 8-methoxypsoralen by mass spectrometry for offline extracorporeal photopheresis.

BACKGROUND: Extracorporeal photopheresis (ECP) is an efficient method to treat various autoimmune diseases, cutaneous T-cell lymphoma, and graft-versus-host disease. It is based on the ex vivo inactivation of lymphocytes by 8-methoxypsoralen (8-MOP)/UV light treatment. Despite the adhesive, lipophilic nature of 8-MOP, no quality control is established for the ECP procedure. METHODS: We developed a sensitive high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) assay to monitor residual 8-MOP concentration after UVA irradiation in the whole blood supernatant after acetonitrile precipitation. RESULTS: The preanalytical stability of 8-MOP exceeded 7 days, allowing batch mode analysis. Linearity was determined with R2 above 0.99. The 8-MOP concentrations decreased exponentially after UV exposure, with decay constants of 0.0259 in plasma and 0.0528 in saline. The recovery of 8-MOP in photopheresates was about 68%, indicating binding to DNA as well as to plastic structures. UVA induced no 8-MOP fragmentation, but caused self-adducts under extreme conditions (10-fold UV dosage). CONCLUSIONS: Detection of 8-MOP proved to be feasible and demonstrated that the doses were in the pharmaceutically active range.