Tissue homogenizates

The FOX assay applied to a skatole oxidation product isolated by HPLC gave a positive result, supporting the contention that it is skatolyl hydroperoxide (40) . Mixtures of 183 and the eight diastereoisomeric hydroperoxides 184 and 185 derived from thymidine (42), as shown in equation 64, can be separated and detected by RP-HPLC with UVD at 229 nm. Each isomer is determined by applying the FOX assay using a capillary reactor heated at 60 °C to provide sufficient time for total oxidation of the Fe(ll) ions, followed by UVD at 596 mn . A commercial kit based on the FOX assay for hydroperoxide determination in plasma, serum and tissue homogenizates appears in Table 2. 

Although the desorption of thallium occurs at relatively low emitter heating currents (20-25 mA) no interference from organic ions can be observed in the investigation of the brain tissue homogenizate. For a FD mass spectrometric investigation, however, the concentration of about 90 mg/1 thallium is high as compared to sample amounts usually required for an alkali metal determination. In order to as-... 

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