Tritium exchange labeling of compounds containing -no21 -I, -c=c-, and -c=o groups

Prediction of retention indexes. I. Structure-retention index relationship on apolar columns

A simple method is reported for predicting the retention index (RI) of a chemical compound from the number of carbon and carbon equivalent atoms in the molecule, the RI increment for atom addition and the group retention factors (GRFs) for substituents and functional groups. Atoms other than carbon such as oxygen, nitrogen, sulfur, chlorine, bromine and iodine are assigned carbon atom equivalency of approximately 1, 1, 2, 2, 3 and 4, respectively and are counted for their contribution towards RI prediction. The GRFs of substituents and functional groups are derived from the RIs of reference compounds and series of homologues. Ring structures, ring fusion, ring connection, iso- and neo-carbons, chain branching and unsaturation are also assigned GRFs. The predicted RIs of a number of alicyclic, aliphatic and aromatic hydrocarbons, primary, secondary and tertiary alcohols, phenols, aliphatic amines, aromatic amines, heterocyclics, carboxylic acids, acid esters, aldehydes, ketones, and halogenated compounds, are found to be within +/- 3% of the observed values. The structure-retention index relationship thus developed is extremely useful in the tentative identification of radioactive side products formed in tritium labeling by radiation-induced methods.

A convenient radiometric assay for flavin-containing monooxygenase activity

A rapid, convenient assay to determine the activity of the flavin-containing monooxygenase is described. The method is based on direct analysis of quenched incubation mixtures by thin-layer chromatography and utilizes tritiated dimethylaniline as the substrate. The synthesis of the radiolabeled substrate is described. The usefulness of dimethylaniline N-oxide formation as a measure of flavin-containing monooxygenase activity was assessed using the purified hog liver enzyme, hog liver microsomes, and liver microsomes from untreated and phenobarbital-pretreated rats.