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

Determination of three chlorophenols in red wine bysweeping- micellar electrokinetic chromatographycoupled with dispersive liquid-liquid microextraction and reversed phase liquid-liquid microextraction

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），300μL 正己烷（萃取剂）；RP-LLME 为：25μL 0.16 mol / L NaOH（萃取剂）。最佳电泳条件：25 mmol / L NaH2 PO4，100 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 NaH2 PO4；压力进样20 s×20.67 kPa（3 psi）。PCP 和 TCP 的线性范围为0.5～100μg / L（ r≥0.9910）， DCP 的线性范围为1.5～80μg / L（r =0.9851）。3种分析物的检出限（ S / N =3）为0.035～0.114μg / 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。

A method of dispersive liquid-liquid microextraction（ DLLME）and reversed phase liquid-liquid microextraction（RP-LLME）procedures coupled with sweeping-micellar electroki-netic 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 5000r / min;for RP-LLME,25 μL 0. 16 mol / L NaOH solution,extraction for 2 min,centrifugation for 2 min at 5000r / min. The optimum running buffer（ pH 2. 3）was an aqueous solution containing 25 mmol / L NaH 2 PO 4 ,100 mmol / L sodium dodecyl sulfate（ SDS）and 30% （ v / v）acetonitrile. The opti-mum on-line concentration conditions were as follows：sample matrix,80 mmol / L NaH 2PO 4;hydrodynamic injection of 20 s at 20. 67 kPa（3 psi）. Under the optimum conditions,the excel-lent linearity was obtained over the range of 0. 5-100 μg / L（r≥0. 991 0）for PCP and TCP,and 1. 5-80 μg / L（ r≥0. 985 1）for DCP. The limits of detection（ S / N = 3）were in the range of＆amp;nbsp;0. 035-0. 114 μg / L. The average recoveries were in the range of 75. 2% -104. 7% with the rela-tive 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 matri-xes and other weak acidic organic contaminants.