Fully automatic exposed and in-syringe dynamic single-drop microextraction with online agitation for the determination of polycyclic musks in surface waters of the Pearl River Estuary and South China Sea.

An automatic exposed and in-syringe dynamic single-drop microextraction method (SDME) for the determination of five polycyclic musks in natural waters was developed using gas chromatography with mass spectrometry. Online agitation was first introduced to the automatic SDME with a magnetic mixer fixed to the bottom of the sample tray of the autosampler. A high enrichment factor (110 ∼182) for the target analytes could be achieved after several parameters that affected the microextraction were optimized. The recoveries were between 84.9 and 119.5%, while the limit of detection ranged from 3.4 to 11 ng/L with relative standard deviation < 11.1% for the polycyclic musks. This new SDME mode is fully automatic with great convenience, high enrichment and good reproducibility, and no human intervention. The proposed method was, therefore, successfully applied to determine the polycyclic musks in 31 surface sea waters that were collected from the Pearl River Estuary and the South China Sea. Most polycyclic musks could be detected with the total concentrations ranging from 58.9 to 528.5 ng/L. By using spatial interpolation method of ordinary kriging, the most contaminated area was found near the cities of Dongguan and Guangzhou with local discharge via the major rivers.