A single-step synthesized supehydrophobic melamine formaldehyde foam for trace determination of volatile organic pollutants

Superhydrophobic materials have attracted many attentions in recent years while their application in sample preparation remained almost intact. In this project, a rough surface of melamine formaldehyde foam was silanized by chemical deposition of trichloromethylsilane to form a highly porous and superhydrophobic material, presumably a suitable medium for extracting non-polar compounds such as benzene and its methyl derivatives. The prepared sorbent was packed in a needle for the headspace needle-trap microextraction of benzene, toluene, ethylbenzene and xylenes (BTEX). Major parameters associated with the extraction/desorption processes were considered for optimization. Under the optimized condition, the linear dynamic range was from 20 to 1000 ng L−1 (R2 > 0.98). For evaluating the method precision, inter-day, intra-day and needle-to-needle relative standard deviations (RSD%) were calculated (<13%) for water samples spiked at 500 ng L−1 of BTEX. The LOD values were in the range of 5-10 ng L−1 using gas chromatography-flame ionization detector (GC-FID). Finally, hookah water was considered as suspicious real sample, assumed to contain volatile organic pollutants. Among these pollutants, toluene was identified, at the concentration level of 439 ng L−1, in one of the hookah samples while benzene was detectable at much lower level. Also, some other organic pollutants were identified in the smoke and hookah water using GC-mass spectrometry (GC-MS). In addition, the suspicious BTEX-containing samples from petrochemical waste water of Asalooye (Persian Gulf) were analyzed.