Abstract:

The α-cyclodextrin(CD) modified organic monolithic materials were synthesized and applied for the enrichment of polyaromatic compounds from environmental samples. Application of the modified materials in the solid extractionroom temperature phosphores(SPE-RTP) were studied and compared. The room temperature phosphorescence behaviors of 14 organic compounds on the α-CD modified substrate were examined. Compared with the β-CD modified material, the α-CD modified monolithic materials have less RTP background and therefore better sensitivity as well as enrichment capabilities for the double ring aromatic substances. The partition constants of naphthlene and 7,8-benzoquinolin on α-CD modified monolith were found to be 5.03×103 and 2.94×102, respectively, indicating that α-CD modified monolith has higher selectivity for naphthlene. Naphthol can form inclusion complex also with α-CD modified monolith. However, because of the large polarity and solubility in water, the extraction efficiency at higher concentration is relatively low. The largest enrichment volume for the concentration of 5×10-11 mol/mL naphthlene is 300 mL. With SPE-RTP, the detection limits for naphthlene and 7,8-benzoquinolin are 9.80×10-12 mol/mL and 4.60×10-11 mol/mL, respectively. The linear ranges are 5.00×10-11~8.00×10-9 mol/mL and 6.00×10-11~5.00×10-10 mol/mL, respectively, with RSD less than 3.7%. α-CD modified membrane was applied to the determination of naphthalene in polluted soil samples and results were further verified by GC-MS. With one step extraction by cyclohexane and then followed by SPE-RTP, naphthlene can be selectively concentrated from soil samples. With 0.012 8 mg naphthlene spiked in the soil samples, the recovery is (104.9±6.5)%. The concentration of naphthlene in the soil samples was determined as (5.61±0.12) mg/kg, which was in accord with the results of GC-MS.

Key words: Organic polymeric monolithic substrate, α-cyclodextrin, solid phase extraction, room temperature phosphorescence, polycyclic aromatic hydrocarbon