The Effective Carbon Number of Chlorobenzenes

Detector response of 12 chlorobenzenes was investigated (mono-, di-, tri-, tetra-, penta-, and hexachlorobenzene, CBs) using flame ionization detector in a capillary gas chromatographic system. We determined the signal-reducing effect of the chlorine atom on the aromatic ring relative to the number of the chlorine substituents and expressed with the effective carbon number (ECN). Benzene was applied as a reference substance. Using the signal-modifying pattern of the chlorine atoms on the benzene's response, we developed an alternative calibration measurement method (CBs-ECN method) for the 12 CBs and compared it with classic calibration. The differences in the concentrations calculated by the two quantitative methods were under 4.5% for 11 CBs and 7% for one compound.Taking advantage of the opportunities provided by the CBs-ECN pattern it is not necessary to apply all of the 12 CBs but only one single component, the hexachlorobenzene for the calibration. With this simplification, the preparation of the calibration standards is faster, does not require purchasing all 12 CBs for each subsequent calibration, and the exposure to harm and expenses are reduced.