Key Laboratory of Analytical Chemistry for Biology and Medicine, Ministry of Education, Department of Chemistry, Wuhan University, Wuhan 430072, China.
J Chromatogr A. 2013 Feb 22;1278:8-15. doi: 10.1016/j.chroma.2012.12.061. Epub 2013 Jan 8.
A new concept of "dual-phase dual stir bar sorptive extraction (SBSE)" was proposed to simultaneously extract six preservatives with different polarities (logKo/w values of 1.27-3.41), namely, benzoic acid (BA), sorbic acid (SA), methyl p-hydroxybenzoate (MP), ethyl p-hydroxybenzoate (EP), propyl p-hydroxybenzoate (PP), and butyl p-hydroxybenzoate (BP). The dual-phase dual SBSE apparatus was consisted of two differently coated stir bars, a 3-aminopropyltriethoxysilane (APTES)-hydroxy-terminated silicone oil (OH-TSO)-coated stir bar that was prepared by sol-gel technique and a C(18) silica (C(18))-polydimethylsiloxane (PDMS)-coated stir bar that was prepared by adhesion. In dual-phase dual SBSE, the two stir bars with different coatings were placed in the same sample solution for the simultaneous extraction of the target analytes with different polarities, and then the bars were desorbed in the same desorption solvent. The extraction performance of the dual-phase dual SBSE for the six preservatives was evaluated by comparing with the conventional SBSE (individual stir bar) with different coatings, including commercial PDMS, homemade PDMS, C(18)-APTES-OH-TSO, APTES-OH-TSO, and C(18)-PDMS. The experimental results showed that the dual-phase dual SBSE had the highest extraction efficiency for the six target preservatives. Based on this fact, a novel method by combining the dual-phase dual SBSE which was consisted of the APTES-OH-TSO-coated and C(18)-PDMS-coated stir bars with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was developed for the simultaneous analysis of six target beverage preservatives in beverages. Under optimal conditions, the limits of detection (LODs) for six target preservatives ranged from 0.6 to 2.7 μgL(-1) with the relative standard deviations (RSDs) of 4.6-9.2% (C(BA,SA)=5 μgL(-1),C(MP)=20 μgL(-1),C(EP,PP,BP)=10 μgL(-1), n=7). The enrichment factors (EFs) were approximately 16-42-fold (theoretical EF was 50-fold). The proposed method was validated by the analysis of six target preservatives in three kinds of beverage samples, and the recoveries for the spiked samples were in the range of 76.6-118.6% for cola, 74.6-17.5% for orange juice, and 83.0-119.1% for herbal tea, respectively.
提出了一种新的“双相双搅拌棒吸附萃取（SBSE）”概念，用于同时萃取 6 种具有不同极性（logKo/w 值为 1.27-3.41）的防腐剂，分别为苯甲酸（BA）、山梨酸（SA）、对羟基苯甲酸甲酯（MP）、对羟基苯甲酸乙酯（EP）、对羟基苯甲酸丙酯（PP）和对羟基苯甲酸丁酯（BP）。双相双 SBSE 装置由两根不同涂层的搅拌棒组成，一根是通过溶胶-凝胶技术制备的 3-氨丙基三乙氧基硅烷（APTES）-端羟基硅油（OH-TSO）涂层搅拌棒，另一根是通过附着制备的 C（18）硅胶（C（18））-聚二甲基硅氧烷（PDMS）涂层搅拌棒。在双相双 SBSE 中，将两根具有不同涂层的搅拌棒放置在同一测试溶液中，同时萃取具有不同极性的目标分析物，然后将棒在同一解吸溶剂中解吸。通过与不同涂层的常规 SBSE（单个搅拌棒）进行比较，评估了双相双 SBSE 对六种防腐剂的萃取性能，包括商业 PDMS、自制 PDMS、C（18）-APTES-OH-TSO、APTES-OH-TSO 和 C（18）-PDMS。实验结果表明，双相双 SBSE 对六种目标防腐剂的萃取效率最高。基于这一事实，提出了一种将由 APTES-OH-TSO 涂层和 C（18）-PDMS 涂层搅拌棒组成的双相双 SBSE 与高效液相色谱-紫外检测（HPLC-UV）相结合的新方法，用于同时分析饮料中的六种目标饮料防腐剂。在最佳条件下，六种目标防腐剂的检测限（LODs）范围为 0.6-2.7 μgL（-1），相对标准偏差（RSDs）为 4.6-9.2%（C（BA，SA）=5 μgL（-1），C（MP）=20 μgL（-1），C（EP，PP，BP）=10 μgL（-1），n=7）。富集因子（EFs）约为 16-42 倍（理论 EF 为 50 倍）。该方法通过对三种饮料样品中六种目标防腐剂的分析进行了验证，加标样品的回收率分别为可乐 76.6-118.6%、橙汁 74.6-17.5%和凉茶 83.0-119.1%。
