Possibilities of analyzing indoor air by gas chromatography using retention index monitoring

Indoor air samples are usually collected in Tenax TA™ adsorbent tubes and analyzed using a thermal desorption cold trap injector combined with GC/MS‐ and/or GC/FID‐ techniques. Often only selected sample tubes can be analyzed using rather expensive GC/MS equipment for compound identification. The identification and quantitation method described here employs a two‐channel high resolution gas Chromatograph equipped with a thermal desorption cold trap injector and two flame ionization detectors. Separation of sample compounds is done using two capillary columns of different polarity stationary phases. Identifications are made by two‐channel retention index monitoring (RIM) using a pattern recognition software for automatic assignment of selected n‐alkane standards from among sample peaks. RIM is suitable for analyzing indoor air samples when (I) preliminary results are needed immediately, (II) the amount of the different sample compounds are on a same concentration level, and (III) tens of similar samples from different sources are to be analyzed. In addition (IV) the method is easy to use in routine laboratory practice.