New extraction of toluene from water samples based on nano-carbon structure before determination by gas chromatography

Toluene enters waters from different industries and has a hazardous effect on the environment and humans. So, accurate determination of toluene in water must be evaluated by new technology. In this study, the carbon nanotube and nitrogen-doped porous graphene (CNTs/ N -DPG) as a carbon nanostructure was used to extract toluene in waters and wastewater samples before being determined by a gas chromatography–flame ionization detector (GC–FID). The toluene was extracted in 20 mL of water samples with 30 mg of CNTs/ N -DPG in the presence of an ultra-sonication accessory by the packed syringe membrane filter solid-phase microextraction. After extraction, the carbon nanostructure was separated from water and standard solution by membrane filter at pH 5.0. The carbon nanostructure extracted on the filter was transferred to a closed gas chromatography vial, and toluene was released in the headspace space of the vial by heat accessory. Finally, the toluene was determined by injecting 10–100 μL of vial air into the gas port of the GC–FID. The main parameters, such as flow rate, amount of adsorbent, pH, and toluene concentration, were studied and discussed. The linear range, the limit of detection, the limit of quantification, and the relative standard deviation (%RSD) were obtained 1–185 μg L −1 , 0.22 μg L −1 , 1.0 μg L −1 , and 1.46, respectively ( n = 10). By the mechanism extraction, the electrostatic force and π – π interaction caused the toluene adsorption process by the carbon nanostructure in the water sample. The proposed methodology was validated with the gas chromatography–mass spectrometry (GC–MS) analyzer. Graphical abstract