Grupo de Investigación y Desarrollo en Química Analítica (QUIANID) (LISAMEN, CCT CONICET-Mendoza), Mendoza, Argentina.
J Chromatogr A. 2010 Oct 8;1217(41):6334-41. doi: 10.1016/j.chroma.2010.08.021. Epub 2010 Aug 13.
Coacervative microextraction ultrasound-assisted back-extraction technique (CME-UABE) is proposed for the first time for extracting and preconcentrating organophosphates pesticides (OPPs) from honey samples prior to gas chromatography-mass spectrometry (GC-MS) analysis. The extraction/preconcentration technique is supported on the micellar organized medium based on non-ionic surfactant. To enable coupling the proposed technique with GC, it was required to back extract the analytes into hexane. Several variables including, surfactant type and concentration, equilibration temperature and time, matrix modifiers, pH and buffers nature were studied and optimized over the relative response of the analytes. The best working conditions were as follows: an aliquot of 10 mL 50 gL(-1) honey blend solution was conditioned by adding 100 μL 0.1 molL(-1) hydrochloric acid (pH 2) and finally extracted with 100 μL Triton X-114 100 gL(-1) at 85°C for 5 min using CME technique. Under optimal experimental conditions, the enrichment factor (EF) was 167 and limits of detection (LODs), calculated as three times the signal-to-noise ratio (S/N=3), ranged between 0.03 and 0.47 ngg(-1). The method precision was evaluated over five replicates at 1 ngg(-1) with RSDs ≤ 9.5%. The calibration graphs were linear within the concentration range of 0.3-1000 ngg(-1) for chlorpirifos; and 1-1000 ngg(-1) for fenitrothion, parathion and methidathion, respectively. The coefficients of correlation were ≥ 0.9992. Validation of the methodology was performed by standard addition method at two concentration levels (2 and 20 ngg(-1)). The recoveries were ≥ 90%, indicating satisfactory robustness of the methodology, which could be successfully applied for determination of OPPs in honey samples of different Argentinean regions. Two of the analyzed samples showed levels of methidathion ranged between 1.2 and 2.3 ngg(-1).
共萃取微萃取超声辅助后萃取技术（CME-UABE）首次被提出，用于从蜂蜜样品中提取和预浓缩有机磷农药（OPPs），然后进行气相色谱-质谱（GC-MS）分析。该萃取/预浓缩技术基于非离子表面活性剂的胶束组织介质。为了使所提出的技术与 GC 耦合，需要将分析物反萃取到己烷中。研究并优化了包括表面活性剂类型和浓度、平衡温度和时间、基质修饰剂、pH 和缓冲液性质在内的多个变量，以优化分析物的相对响应。最佳工作条件如下：将 10 mL 50 gL(-1)的蜂蜜混合溶液加入 100 μL 0.1 molL(-1)盐酸（pH 2），然后使用 CME 技术在 85°C 下用 100 μL Triton X-114 100 gL(-1)萃取 5 min。在最佳实验条件下，富集因子（EF）为 167，检出限（LOD），计算为信噪比（S/N=3）的三倍，范围为 0.03-0.47 ngg(-1)。在 1 ngg(-1)浓度下，通过 5 次重复测定评估方法的精密度，相对标准偏差（RSD）≤9.5%。氯吡硫磷的校准曲线在 0.3-1000 ngg(-1)浓度范围内线性，而杀螟硫磷、对硫磷和甲拌磷的校准曲线分别在 1-1000 ngg(-1)浓度范围内线性，相关系数均≥0.9992。通过在两个浓度水平（2 和 20 ngg(-1)）下进行标准加入法验证了该方法的有效性。回收率≥90%，表明该方法具有良好的稳健性，可成功应用于不同阿根廷地区蜂蜜样品中 OPPs 的测定。两个分析样品的甲拌磷水平在 1.2-2.3 ngg(-1)之间。
