In-situ measurement of trace isoprene and dimethyl sulfide in seawater and oceanic atmosphere based on room temperature adsorption-thermal desorption

Abstract

Abstact Aqueous biogenic gases play an important role in the global environment. Here, we describe a novel method developed to determine trace levels of biogenic gases (isoprene and dimethyl sulfide, DMS) in situ, based on room temperature enrichment-thermal desorption. The two gases from seawater (isoprene: 630 mL; DMS: 20 mL) and the marine atmosphere (1 L) were adsorbed into a funnel-shaped quartz tube at room temperature, then thermally desorbed (358 °C) and introduced into a gas chromatograph-flame ionization detector (GC-FID) using a portable curie-point injector. A suitable adsorbent material (Carbopack X) was added to the adsorption tube to trap two the target compounds in a gas stream for the first time. Good reproducibility (