Sorbent‐packed needle microextraction trap for benzene, toluene, ethylbenzene, and xylenes determination in aqueous samples

Abstract

A needle trap (NT) device filled with Carbopack X as a sorbent material is evaluated for the static headspace analysis of benzene, toluene, ethylbenzene, and xylene (BTEX) compounds in aqueous samples. Injection parameters used with the NT device (e.g. volume of carrier gas and time to open the split valve) are evaluated to determine the mechanism involved during the desorption and transferring of the target compounds into the GC column. Furthermore, different parameters affecting the adsorption capacity of the sorbent are studied (e.g. sampling time and temperature, headspace/sample volume ratio, salting-out, and stirring). The evaluation of the method with aqueous samples shows that repeatability and recoveries with the NT device are equivalent to those obtained using solid-phase microextraction with a carboxen/PDMS (CAR/PDMS) coating. LODs obtained with flame ionization detection are in the range of 10-25 μg/L, and in the range of hundredths of μg/L with MS detection. The method developed is satisfactorily applied to the analysis of aqueous samples obtained from wastewater treatment plants.

Headspace needle-trap analysis of priority volatile organic compounds from aqueous samples: Application to the analysis of natural and waste waters

“…In-tube or in-needle sorptive extraction methods are approaches based 63 on dynamic headspace (HS) that have been developed to overcome the relatively limited 64 concentration capacity of SPME [10]. Needle-trap devices (NTD's), summarized details static [9,19,20]. In all these studies, benzene, toluene, ethylbenzene and xylenes…”

Needle-type Extraction Device Designed for Rapid and Sensitive Analysis in Gas Chromatography

“…The extracted analytes can then be thermally desorbed in the heated GC injection port, typically without a desorption solvent. 31,33,34 For desorption of the extracted analytes from the sorbent, there are two types of desorption methods: one uses carrier gas flow as the desorption gas, [32][33][34][35][36][37] while another way is not using a carrier gas. When not using a carrier gas, the flow of an inert gas, supplied from a gas tight syringe, was used as the desorption gas.…”

“…44,45 The determination of VOCs in aqueous samples by needle-type extraction device was also reported. [36][37][38][45][46][47] …”

“…46 Crom et al also reported the determination of BTEX in aqueous samples using a Carbopack X-packed needle, where several experimental parameters were systematically optimized. 36 Additionally, the same research group compared two techniques, headspace and PT, for the analysis of VOCs in aqueous samples using a needle extraction device. They concluded that PT analysis showed a better sensitivity.…”

Multivariate optimization of headspace-GC for the determination of monoaromatic compounds (benzene, toluene, ethylbenzene, and xylenes) in waters and wastewaters

“…Therefore, they can contaminate extensively the air, soils and surface, or underground waters [7][8][9][10]. The main sources of BTEX contamination are atmospheric deposition, leaks from underground fuel storage tanks or pipelines, inadequate effluent disposal, accidental spills of petroleum products during transport, and leaching from landfill [11][12][13][14][15][16].…”