Study On Subcritical Water Extraction-solid Phase (Micro) Extraction

Static subcritical water extraction along with simultaneous solid-phase extraction has been used for the analysis of organochlorinated pesticides (OCPs), i.e. α-HCH,β-HCH,γ-HCH,δ-HCH and HCB in sediments. A rapid and without organic solvents method for determining chlorophenols (CPs), i.e. 2-CP,4-C-3MP,2,4-DCP,2,4,6-TCP and PCP in sediments by combination of static subcritical water extraction with solid-phase microextraction has been developed too. The primary achievements are as following:The operation parameters of GC-ECD were optimized and the detection limits of 0.1-30μg/L were achieved.Activated carbon fiber (ACF), as a new solid phase, has good adsorption capability for OCPs in sediment. With ethyl acetate as eluent, recoveries of OCPs were above 77%.With ACF as solid-phase, recoveries of spiked pesticides were greatest at 225℃ for 60min extraction time by coupling static subcritical water extraction with simultaneous solid-phase extraction . The detected results of OCPs in natural samples from Yaer Lake demonstrated that this method has better selectivity and sensitivity than Soxhlet Extraction (SOX).Solid-phase microextraction with 65μm PDMS/DVB was evaluted for the analysis of CPs in water. With 10min extraction time after equating at 80℃ for 90min,and with saturated salt conditions sample pH<1, the best results were obtained .At 240℃, desorption time of 4min was sufficient.Under the optimized conditions, the recoveries of CPs were 85-105%. Quantitative determinations of CPs in contaminated sediments from Yaer Lake showed good agreement with SOX.