Characterisation of Indoor VOCs

In order to increase the number of compounds that can be separated in a single analysis, it is not unusual to use a combination of GC columns with different polarities [28]. Temperature programming is also often required to achieve acceptable separation of analytes. A typical temperature program which has been used to separate different classes of indoor VOCs is summarised as follows (1) hold at 40 °C for 1 min, (2) raise at 15 °C min to 105 °C, (3) hold at 105 °C for 5 min, (4) raise at 20 °Cmin to 245 °C and (5) hold at 245 °C for 5 min [10]. Column diameters ranging from 0.25 to 0.53 mm and lengths ranging from 25 to 100 m have been employed for indoor VOC measurements [ 10,42,51 ]. The choice of column dimensions depends on the properties of the compounds to be separated. 

In their recent review of the application of GC in environmental analysis, 

Santos and Galceran [15] suggested that future perspectives of GC analysis 

Such developments could impact future indoor VOC measurements markedly. 

HPLC is mainly used for the analysis of the derivatives of low molecular weight carbonyl compounds such as formaldehyde [40, 59, 65]. However, formaldehyde is also quantified by a variety of other procedures, including the spectrometric acetyl-acetone method [66] and the chromotropic acid pro- 

---