Determination of synthetic polycyclic musks in aqueous samples by ultrasound-assisted dispersive liquid-liquid microextraction and gas chromatography-mass spectrometry.

A simple and solvent-minimized procedure for the determination of six commonly found synthetic polycyclic musks in aqueous samples using ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) coupled with gas chromatography-mass spectrometry (GC-MS) is described. The parameters affecting the extraction efficiency of analytes from water samples were systematically investigated. The best extraction conditions involved the rapid injection of a mixture of 1.0 mL of isopropyl alcohol (as a dispersant) and 10 μL of carbon tetrachloride (as an extractant) into 10 mL of water containing 0.5 g of sodium chloride in a conical-bottom glass tube. After ultrasonication for 1.0 min and centrifugation at 5,000 rpm (10 min), the sedimented phase 1.0 μL was directly injected into the GC-MS system. The limits of quantitation (LOQs) were less than 0.6 ng/L. The precision for these analytes, as indicated by relative standard deviations (RSDs), was less than 11% for both intra- and interday analysis. Accuracy, expressed as the mean extraction recovery, was between 71 and 104%. Their total concentrations were determined in the range from 8.3 to 63.9 ng/L in various environmental samples by using a standard addition method.