SIMULTANEOUS DETERMINATION OF ORTHO-XYLENE, META-XYLENE AND PARA-XYLENE BY FLOW INJECTION-FOURIER TRANSFORM INFRARED-SPECTROSCOPY

A method has been developed for the direct simultaneous determination of ortho-, meta- and para-xylene in xylol by Fourier transform infrared spectroscopy. The method is based on the injection of samples, diluted in hexane, into a carrier solution of hexane. The absorbance measurements were carried out at 743, 770 and 796 cm-1, respectively, with a resolution of 4 cm-1. The limit of detection corresponds to 0.03% v/v for ortho- and meta-xylene and to 0.02% v/v for para-xylene using a 0.13 mm pathlength micro flow cell. The method does not require the use of sophisticated cells or complex data treatment, it is precise and provides accurate results in the analysis of spiked and real samples; results obtained are comparable to those found using a reference method based on the ratio of the peak height absorbances of the different compounds studied.