Development of Solid Phase Micro Extraction Technique for Determination of Triazines in Water Samples Using Experimental Design

Abstract

A sensitive direct immersion solid phase microextraction technique coupled with gas chromatography-mass spectrometry (SPME-GC-MS) was optimized and validated for analysis of triazines in drinking water. Preliminary evaluation of fibre materials indicated that carbowax-divinylbenzene was better than poly-dimethyl siloxane-divinylbenzene thus it was selected for further work. Variables namely extraction times, extraction temperature, ionic strength and stirring rate were screened and optimized using a two-level full factorial design and central composite design. The proposed optimized analytical procedures was obtained using sample volume (10 mL), extraction time (50 min), extraction temperature (50 °C), ionic strength (20 % NaCl), stirring rate (240 rpm) and pH (6.5). Desorption time and temperature were 5 min and 250 °C respectively. Recoveries were achieved in the range of 77 to 91.6 % at fortified concentration of 2 μg L^-1. Linearity ranges from 0.02 to 10 μg L^-1 (with r = 0.982 to 0.998). Detection and quantification limits were obtained in the range of 0.004 to 0.047 μg L^-1 and 0.012 to 0.159 μg L^-1 for all targeted compounds. An analysis of triazines in drinking water samples has managed to detect the presence of ametryn in the range of 0.026 to 0.240 μg L^-1.