A low-cost and simple low-pressure solid-phase microextraction device for sampling of volatiles organic compounds in complex solid matrices

A simple, low-cost, reliable vacuum assisted headspace solid-phase microextraction (VA-HS SPME) device was fabricated and evaluated. It was coupled with gas chromatography flame ionization detection (GC-FID) and applied for direct extraction and determination of polycyclic aromatic hydrocarbons (PAHs) in polluted soil samples, without any sample preparation step. The nanostructured octadecyl silica/polyvinyl alcohol (NS-ODS/PVA) was synthesized and coated on a stainless-steel fiber by electrospinning method, as the sorbent. The nanocomposite structure was characterized by Fourier Transfer infrared spectrometry (FT-IR) and scanning electron microscopy (SEM). Parameters affecting the performance of the developed method, including extraction temperature and time, vacuum level, volumes of vacuum chamber and sample vial, and desorption conditions, were investigated and optimized. This sampling strategy enables low LODs and provides a powerful and reliable ultrasensitive method for analysis of PAHs in contaminated solid samples. Under the optimal conditions, good linearity of the calibration curves (R2 > 0.99) was obtained over the concentration range of 0.01-1.0 μg g-1. The limits of detection, limits of quantification and relative standard deviations were found to be in the ranges of 0.05-0.17 ng. g-1, 0.2-0.6 ng g-1 and 9.7-15.4% (n = 6), respectively. For further evaluation, the analytical performances of the proposed method were compared with some of the previously reported methods. The results showed wider LDRs and lower LODs for the developed procedure, compared with the published reports. Finally, the proposed VA-HS SPME method was successfully applied for the extraction and determination of PAHs in contaminated soil samples.