Fully Automated Headspace Bubble-in-Drop Microextraction.

A fully automated headspace bubble-in-drop microextraction (automated HS-BID) method, coupled to gas chromatography/mass spectrometric (GC/MS) analysis, was developed for the analysis of nitro musks in environmental water samples. The entire procedure, including the extraction of the analytes by HS-BID and GC/MS analysis of the analyte-enriched solvent, was completely automated. In BID, a certain volume of air is introduced into the extraction solvent droplet, enlarging the surface area of the extraction solvent droplet in relation to the water sample without increasing its volume, significantly enhancing extraction efficiency. Compared to conventional single drop microextraction, the developed method has higher extraction efficiency due to the enlarged surface area of the extraction solvent droplet. Under the optimized conditions (1.0 mL of sample solution, using 1.0 μL of 1-octanol containing of 0.5 μL of air bubble, at 40 °C for extraction for 20 min), the automated HS-BID gave low limits of detections (between 0.012 and 0.042 μg/L), good linearity (from 0.1 to 20 μg/L and from 0.2 to 50 μg/L, with r(2) between 0.9909 and 0.9958, depending on analytes), and good repeatability of the extractions (relative standard deviations, below 4.7%, n = 5). The developed procedure was applied to determine nitro musks in environmental water samples and was demonstrated to be efficient, labor-free, economical, and environmentally benign.