Microwave‐assisted process (MAP™): Application to the headspace analysis of VOCs in water

Abstract

AbstractA method combining the techniques of microwave‐assisted process (MAP) and gas chromatography (GC) has been developed for the determination of volatile organic compounds in water. For comparison purposes, MAP and conventional gas‐phase extractions using static headspace methods were performed on laboratory‐spiked water samples. The analytes used as models in this preliminary investigation were benzene, toluene, ethylbenzene, chlorobenzene, o‐, m‐, and p‐xylenes, and 1,2‐, 1,3‐, and 1,4‐dichlorobenzenes. MAP uses microwaves to very rapidly heat the bulk of the matrix and achieve a selective vaporization of the analytes that are then transferred onto the gas chromatographic apparatus via identical sampling conditions. The method was tested over a 10–5000 ppb range and proved capable of yielding excellent linearity (R2 > 0.99999) and precision (RSD 1.4%). Compared to the conventional static headspace extraction method, the MAP extraction method offered enhanced sensitivity as evidenced by a response in signal greater by 35% for aliquots from the same aqueous solutions. This level of performance is achieved within one minute of overall sample preparation time for the MAP method, whereas the conventional static headspace method used for comparison purposes required 30 minutes of equilibration time. Similar performance was observed with actual samples.