Sampling volatile organic compounds using a modified solid phase microextraction device

Headspace solid phase microextraction (headspace SPME) has been demonstrated to be an excellent solvent‐free sampling method. One of the major factors contributing to the success of headspace SPME is the concentrating effect of the fiber coating toward organic compounds. The affinity of the fiber coating toward very volatile analytes, such as chloromethane, may, however, not be large enough for detection at the parts per trillion concentration level. Static headspace analysis, on the other hand, is very effective for these very volatile compounds. As analyte volatility decreases, the sensitivity of static headspace analysis drops. The complementary nature of these two sampling methods can be exploited by combining the SPME device with a gastight syringe. The sensitivity of the new sampling device is better than that of SPME for very volatile compounds or that of static headspace analysis for less volatile compounds. This new method can sample a wide range of compounds from chloromethane (b.p. −24°C) to bromoform (b.p. 149°C) with estimated limits of detection at the low parts per trillion level.