Cooling/heating assisted needle trap instrument by cotton/graphene/aminosilica nanocomposite sorbent packed for analysis of organic compounds in soil samples

In NTD and other headspace methods, the analytes by applying temperature were release from the matrix and adsorb on sorbent (fiber coating, needle sorbent or…). The temperature has a bilateral effect, in one way increased the release of analytes from matrix, in another way at higher temperature the sorbent temperature increased, then its efficiency decreased, so an optimum low temperature choose. However, some samples particularly solid samples, for the release of their analytes required high temperature [1-3]. To compensate these limitations, cold-fiber SPME (CF-SPME) was introduced [4]. In this research, a new cooling/heating instrument based thermoelectric cooler (CH-TEC) was designed, constructed and optimized. The CH-TEC instrument was used for cooling the needle sorbent and heating the sample matrix simultaneously in needle trap device (NTD) method. This instrument was applied for the extraction of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil samples followed by gas chromatography coupled flame ionization detector (GC-FID) determination. Covalent attachment of aminosilica/graphene oxide nanocomposite to cotton (Cot/GO/Si) was synthesized and applied as a sorbent for packing inside NTD. The CH-TEC-NTD-GC-FID method was compared to the NTD-GC-FID method and also Cot/GO/Si nanocomposite sorbent was compared to commercial PDMS and C18 sorbents. Finally, this method was performed for extraction and determination of PAHs in contaminated soil samples.