Purge- trap Gas Chromatography and Mass Spectrometric Method for Analysis of Isoprene in Natural Waters

Gas chromatography with mass spectrum detector (GC-MSD) coupled with purge-and-trap system was developed to analyze the concentration of isoprene in natural waters. The experimental conditions were optimized, including purge gas flow rate (50 mL min−1), purge time (15 min), capillary column (Rt-Alumina BOND/KCl) and its appropriate temperature programming. The precision was less than 4% (n = 6), the detection limit was 0.5 pM, and the recovery was 91%–102%. The analytical results of preservative experiments showed that no obvious variation was observed in the concentrations of isoprene within 60 days under the preservation conditions. The concentrations of isoprene measured with the method ranged from 60.8 pM to 278.7 pM in the Jiaozhou Bay and its adjacent river estuaries, and from 44.7 pM to 77.2 pM in the Yellow River estuary, respectively, which were in good accord with those reported in literatures in other coastal waters. In conclusion, the analytical method meets completely the requirements of the analysis of concentration of isoprene in natural waters.

Graphical AbstractA purge-and-trap system coupled with GC/MSD was used for the analysis of volatile organic compounds in natural waters. After extraction and cooling trap by ultra-high-purity N2 and liquid N2 respectively, volatile isoprene was desorbed with boiling water and then induced into GC/MSD for measurement.Figure optionsDownload as PowerPoint slide