6169

6169

بيييييييييييييييييييي

كارشناسي ارشد

فيزيك

يببيب

يببيب

ثبثبثب

يزز

Abstract CMK-1 typed ordered nanoporous carbon was investigated as a novel solid phase microextraction fiber for the first time. The structural order and textural properties of the prepared materials were studied by XRD, SEM and nitrogen adsorption. The microextraction process was coupled with GC-FID and used to extract BTEX and MNT from the head space of the solution samples. Prepared fibers featured advantages like easy and fast preparation together with high thermal and mechanical resistance which a fiber could be used for more than 60 tests. Using the Taguchi method, an orthogonal array design (OAD), OA16 (45) was employed to optimize the HS-SPME of BTEX and BTEX. Five relevant factors, i.e. sample volume, stirring rate, ionic strength, extraction time and temperature were selected and the effects of each factor were studied at four levels on the extraction efficiency of BTEX and MNT compounds and optimized. Based on the results obtained from the analysis of variance (ANOVA), the optimum conditions for extraction BTEX were established as: 12 ml sample volume; vial temperature : laboratory temperature; 8 % (w/v) NaCl ; 30 min extraction time and stirring rate of 1200rpm. Based on the results obtained from the analysis of variance (ANOVA), the optimum conditions for extraction MNT were established as: 12 ml sample volume; 60°C; 8 % (w/v) NaCl ; 30 min extraction time and stirring rate of 600rpm.Under the optimized conditions and for all BTEX components, the linearity was from 3 to 800 μg L−1, the relative standard deviation (RSD%) of the method was between 4.21 and 9.37% and limit of detections (LODs)were between 0.27 and 1.1 μg L−1.The recovery values were from 87.1% to 106.25% in water samples. Under the optimized conditions and for all MNT components, the linearity was from 0.5 to 400 μg L−1, the relative standard deviation (RSD%) of the method was between 3.75 and 4.25% and limit of detections (LODs) were between 0.01 and 0.16 μg L−1.The recovery values were from 89.6% to 108.8% in water samples. Finally, the applicability of the proposed method was evaluated by the extraction and determination of BTEX in the real water samples and petrochemical samples.