分散液液微萃取-反相液液微萃取-扫集-胶束电动色谱法测定红酒中的3种氯酚类物质

建立了分散液液微萃取（DLLME）-反相液液微萃取（RP-LLME）-扫集-胶束电动色谱富集模型，并用于红酒中五氯酚（PCP）、2，4，6-三氯酚（TCP）和2，4-二氯酚（DCP）3种氯酚的测定。实验考察了两步微萃取的萃取参数对氯酚萃取率的影响和样品分离富集的电泳条件。最佳萃取条件DLLME为：3.5 mL红酒（pH 3.0，120 g/L NaCl），300 μL正己烷（萃取剂）；RP-LLME为：25 μL 0.16 mol/L NaOH（萃取剂）。最佳电泳条件：25 mmol/L NaH₂PO₄，100 mmol/L十二烷基硫酸钠（SDS），30%（v/v）乙腈，pH 2.3；分离电压-15 kV；样品基质为80 mmol/L NaH₂PO₄；压力进样20 s×20.67 kPa（3 psi）。PCP和TCP的线性范围为0.5~100 μg/L（r≥0.9910），DCP的线性范围为1.5~80 μg/L（r=0.9851）。3种分析物的检出限（S/N=3）为0.035~0.114 μg/L，加标回收率为75.2%~104.7%，相对标准偏差≤6.17%。该方法富集倍数高、灵敏度高、重现性好、分析速度快，可为不同样品基质中痕量氯酚污染物及某些弱酸性有机污染物测定提供参考。

Determination of three chlorophenols in red wine by sweeping-micellar electrokinetic chromatography coupled with dispersive liquid-liquid microextraction and reversed phase liquid-liquid microextraction

A method of dispersive liquid-liquid microextraction (DLLME) and reversed phase liquid-liquid microextraction (RP-LLME) procedures coupled with sweeping-micellar electrokinetic chromatography (sweeping-MEKC) was established to extract and determine the three chlorophenols (CPs) including pentachlorophenol (PCP), 2,4,6-trichlorophenol (TCP) and 2,4-dichlorophenol (DCP) in red wine. The influences of the parameters of two extraction steps and the electrophoresis conditions were investigated. The optimum extraction conditions were as follows: for DLLME, 3.5 mL red wine sample (pH 3.0, 120 g/L NaCl), 300 μL hexane (extraction solvent), extraction for 3 min, centrifugation for 3 min at 5000 r/min; for RP-LLME, 25 μL 0.16 mol/L NaOH solution, extraction for 2 min, centrifugation for 2 min at 5000 r/min. The optimum running buffer (pH 2.3) was an aqueous solution containing 25 mmol/L NaH₂PO₄, 100 mmol/L sodium dodecyl sulfate (SDS) and 30% (v/v) acetonitrile. The optimum on-line concentration conditions were as follows: sample matrix, 80 mmol/L NaH₂PO₄; hydrodynamic injection of 20 s at 20.67 kPa (3 psi). Under the optimum conditions, the excellent linearity was obtained over the range of 0.5-100 μg/L (r≥0.9910) for PCP and TCP, and 1.5-80 μg/L (r≥0.9851) for DCP. The limits of detection (S/N=3) were in the range of 0.035-0.114 μg/L. The average recoveries were in the range of 75.2%-104.7% with the relative standard deviations (RSDs) not more than 6.17%. The results indicated that the proposed method may find wide applications for the determination of trace CPs in various sample matrixes and other weak acidic organic contaminants.