QSAR aided design and development of biopolymer-based SPE phase for liquid chromatographic analysis of polycyclic aromatic hydrocarbons in environmental water samples

A solid-phase extraction (SPE), using starch based biopolymer adsorbent, coupled with high performance liquid chromatography-fluorescence/UV detectors (HPLC-FLD/UV) method was developed for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. Quantitative structure activity relationship was employed for assessing the suitability of epichlorohydrin, 1,6-hexamethylene diisocyanate and 4,4-methylene diphenyl diisocyanate (MDI) based starch, beta- and gamma-cyclodextrin biopolymers as the SPE sorbent phases, via density functional theoretical (DFT) modeling studies. The DFT parameters showed that MDI based biopolymers exhibited the highest retention potential as the SPE sorbent. The modelled materials were synthesized, characterized and evaluated for the extraction of (PAHs). The results of the screening SPE studies were in agreement with DFT quantum predictions. MDI-starch biopolymer was therefore selected as the best SPE phase. The calibration curves of extracted PAHs were linear in the range of 0.5-50.0 mu g L-1, with r(2) values of > 0.99. The method attained good precisions values of 6.9-26.0 and 0.4-16.6% for UV and FLD detectors respectively; and the method detection limits values of 22.9-155.3 and 0.5-24.2 ng L-1 for UV and FLD detectors respectively. The optimized method was successfully applied for the determination of 16 PAHs in real environmental water samples, and mean recoveries were predominantly >80% for tap and river water samples in both UV and FLD analysis. The values of SPE performance indicators showed that the developed biopolymer phase is better than similar studies reported in literature, and equally comparable to commercially available C-18 SPE phases.