保留时间两点校正反相高效液相色谱法测定持久性有机污染物的正辛醇-水分配系数

Determination of n-octanol /water partition coefficients for persistent organic pollutants by reversed-phase high performance liquid chromatography with dual-point retention time correction

采用改进的反相高效液相色谱法(RP-HPLC)测定了持久性有机污染物(POPs)包括多环芳烃(PAHs)、多氯二苯并二恶英(PCDDs)、多氯二苯并呋喃(PCDFs)和十溴二苯乙烷(DBDPE)等的正辛醇-水分配系数(logKow)。采用保留时间双点校正法(DP-RTC)校正因色谱柱老化等引起的保留时间漂移。以37种有可靠logKow实验值的苯系物、PAHs、PCDD/Fs类似物为模型化合物,建立了logKow和外推至纯水相的保留因子logkw的定量结构-色谱保留关系(QSRR)模型,回归方程为logKow=(1.18±0.02)logkw+(0.36±0.11),其相关系数(R2)为0.985,交叉验证相关系数(R2cv)为0.983,标准偏差(SD)为0.16。进而,用4个已有可靠logKow实验值的验证化合物(联苯、芴、PCDD 1和PCDF 114)对模型进行了外部验证,表明RP-HPLC测得的logKow值与摇瓶法/慢搅法结果有很好的一致性,尤其是对疏水性强的化合物。采用该模型测定了29种特别受关注的POPs的logKow值,这些化合物的logKow实验值均未见报道。所建立的DP-RTC-HPLC是测定强疏水性POPs的logKow值的一种值得推荐的方法。

n-Octanol / water partition coefficients （ logKow ） for persistent organic pollutants （POPs）including polycyclic aromatic hydrocarbons（ PAHs）,polychlorinated dibenzo-p-diox-ins （ PCDDs ）, polychlorinated dibenzofurans （ PCDFs ） and decabromodiphenylethane （DBDPE）have been determined by a modified method of reversed-phase high performance liq-uid chromatography（RP-HPLC）. A dual-point retention time correction（DP-RTC）was used to rectify chromatographic retention time（ tR ）shift resulted from stationary phase aging and so on. Based on this correction,the relationship model between logKow and logkw ,the logarithm of the retention factor extrapolated to pure water,was trained by a set of model compounds（a total of 37）with reliable experimental logKow as training set,including benzene homologues, PAHs and PCDD / Fs-related compounds. A linear regression equation of logKow =（1. 18±0. 02） logkw ＋（0. 36±0. 11）was established with correlation coefficient（R2 ）of 0. 985,cross-validated correlation coefficient（ R2cv ）of 0. 983 and standard deviation（ SD）of 0. 16. This quantitative structure retention relationship（ QSRR） model was further validated using four verification compounds,biphenyl,fluorene,PCDD 1 and PCDF 114,with reliable experimental logKow val-ues. The RP-HPLC-determined Kow values showed good consistency with shake-flask（SFM）or slow-stirring（ SSM）results,especially for highly hydrophobic compounds. Then,the logKow values for 29 POPs of wide interest were evaluated by the improved RP-HPLC method for the first time. The DP-RTC-HPLC method is recommended for the determination of the logKow val-ues of POPs with strong hydrophobicity.