An isotopic labeling method for determining production of volatile organohalogens by marine microalgae

Abstract

An isotopic method has been developed to establish the biological production of volatile organohalogens. The marine microalgae Porphyridium purpureum and Dunaliella tertiolecta were grown in seawater medium containing NaH13CO3, and volatile organohalogens were extracted and analyzed by gas chromatography-mass spectrometry (GC-MS). Isotopically labeled methyl halides were formed in each microalgal culture, and the 13CHCl3 found in the P. purpureum culture confirmed the production of chloroform reported by Scarratt and Moore (Limnol. Oceanogr. 1999. 44: 703-707). No incorporation of 13C into dichloromethane was observed, even though slightly increased CH2Cl2 concentrations were detected in both algal cultures at the end of the incubation period.