THE DETERMINATION OF 5-HYDROXYTRYPTAMINE, RELATED INDOLEALKYLAMINES AND 5-HYDROXYINDOLEACETIC ACID IN THE BOVINE EYE BY GAS-CHROMATOGRAPHY NEGATIVE-ION CHEMICAL-IONIZATION MASS-SPECTROMETRY

Methods were developed for the analysis of 5-hydroxytryptamine, relate d indolealkylamines (tryptamine, melatonin, 5-methoxytryptamine, N-ace tyl-5-hydroxytryptamine and 6-hydroxymelatonin) and 5-hydroxyindole-3- acetic acid (5HIAA) in bovine retina, aqueous and vitreous humours. 5- Hydroxytryptamine and related indolealkylamines were extracted and der ivatized to form their corresponding pentafluoropropionyl spirocyclic derivatives. 5HIAA was extracted and derivatized to the corresponding pentafluoropropionamide-trifluoroethyl derivative. Identification and quantitation by gas chromatography-negative ion chemical ionization ma ss spectrometry was made with reference to deuteriated internal standa rds. 5-Hydroxytryptamine was present in all (n = 34) retinal samples a nalysed (20.53 +/- 1.64 ng) while N-acetyl-5-hydroxytryptamine was det ected in half of the samples of retina (0.06 +/- 0.02 ng). Melatonin ( 0.15 +/- 0.06 ng) and tryptamine (0.78 +/- 0.34 ng) were detected in o nly a small number of retinas. 5-Methoxytryptamine was not present in retina. 5-Hydroxytryptamine was also present in aqueous (0.76 +/- 0.17 ng ml-1) and vitreous (0.35 +/- 0.05 ng ml-1) humours from bovine eye . Tryptamine, melatonin, 5-methoxytryptamine and N-acetyl-5-hydroxytry ptamine were not detected in bovine aqueous and vitreous humours. 5HIA A was found in both bovine aqueous (2.03 +/- 0.38 ng ml-1) and vitreou s (0.65 +/- 0.06 ng ml-1) humours, but its consistent determination in retina was obviated by interference from spurious peaks.