An innovative chemometric approach for simultaneous determination of polycyclic aromatic hydrocarbons in oil-contaminated waters based on dispersive micro-solid phase extraction followed by gas chromatography

In the present study, an analytical strategy was developed using reduced graphene oxide (rGO) as an effective sorbent in dispersive micro-solid phase extraction (DMSPE) for simultaneous determination of seven polycyclic aromatic hydrocarbons (PAHs) combined with gas chromatography (GC-FID). rGO was synthesized using modified Hummer's method and characterized using scanning electron microscope (SEM), atomic force microscope (AFM) and Raman spectroscopy. A rotatable central composite design (CCD) combined with multiple linear regression (MLR) and analysis of variance (ANOVA) was used for designing, modelling and optimization of the extraction procedure. In this regard, principal component analysis (PCA) was used to develop a general response using the scores on the first PC instead of GC peak areas of seven PAHs to develop a global model. Finally, optimum DMSPE conditions were found as 0.7 mL sorbent volume, 0.05 mg mL(-1) sorbent amount, 2.2 mL sample volume, 0.5 mL solvent extraction volume, 7.8 w w(-1) salt concentration and 20 min vortex time. The optimized method was then used for identification and quantification of target PAHs in standard and real samples using partial least squares regression (PLSR). Multivariate analytical figures of merit (AFOMs) for PLS model including sensitivity (SEN), analytical sensitivity (gamma), limit of detection (LOD) and limit of quantitation (LOQ) were calculated by focusing on estimation of signal and concentration which were in the range of (0.37-1.19), (0.87-2.49), (2.39-10.36 ng mL(-1)) and (7.17-21.36 ng mL(-1)), respectively. Thoroughly, multivariate analytical figures of merit were better than univariate ones. Finally, the proposed strategy was successfully tested for the analysis of real oil-contaminated sea water samples. The relative recovery (RR) and relative standard deviation (RSD) were in the range of (9.6-96.86) and (1.54-28.44), respectively.