【摘要】 建立了水中酚类化合物的原位乙酰化-顶空固相微萃取/气相色谱-质谱联用测定方法,并采用响应曲面法中的中心组合设计对实验进行过程优化,选取经单因子实验证实为非单调变化的连续变量,即衍生化试剂(乙酸酐)、衍生化助剂(Na2HPO4)以及反应/萃取温度3个重要因子,以标准化后的峰面积(应变量,代表相对萃取效率)为响应因子,经后退式多元拟合建立萃取应变量与3个自变量的函数关系,F检验和回归系数(r2)表明函数关系显著。基于这些函数关系,以求最值方式获得了不同酚类化合物的最适宜测定条件。不同性质酚类化合物的最适宜条件有较大差异,尤其是反应/萃取温度与其沸点有较好的对应关系,Na2HPO4用量则与各化合物的解离常数(pKa)有关。更多还原

【Abstract】 An in-situ acetylation solid phase microextraction(SPME)/gas chromatography-mass spectrometry was developed for the determination of phenolic compounds in water using central composite designs of the response surface methodology in the process of optimization experiments.Three important response factors,namely derivatization reagent(acetic anhydride),derivatization agent(Na2HPO4) and reaction/extraction temperature,confirmed by the single factor experiments to be the continuous variables of non-monotonic change in the derivatization and extraction processes were selected.Taking the normalized peak area,i.e.the dependent variable representing relative extraction efficiency,as the optimizing target,quantitative relationships between the relative extraction amount and the three independent factors were established with the backward multi-regression fitting.Results of the variance analysis revealed the regression was significant with the lowest F and P value at 6.3 and 0.002 8,respectively.In addition,the variance analysis indicated that the temperature effect was the most significant,the amount of Na2HPO4 next and acetic anhydride the least.Results also showed that the optimum conditions were quite different for different phenolic compounds,since the reaction / extraction temperatures were related to their boiling points and the Na2HPO4 amount was related to their dissociation constants(pKa).更多还原