Sakamoto Mitsushi, Tsutsumi Taizou
Tokushima Prefectural Institute of Public Health and Environmental Sciences, 5-71 Bandai-cho, Tokushima-shi, Tokushima 770-0941, Japan.
J Chromatogr A. 2004 Feb 27;1028(1):63-74. doi: 10.1016/j.chroma.2003.11.066.
The applicability of headspace solid-phase microextraction (HS-SPME) to pesticide determination in water samples was demonstrated by evaluating the effects of temperature on the extraction of the pesticides. The evaluations were performed using an automated system with a heating module. The 174 pesticides that are detectable with gas chromatograph were selected objectively and impartially based on their physical properties: vapor pressure and partition coefficient between octanol and water. Of the 174 pesticides, 158 (90% of tested) were extracted with a polyacrylate-coated fiber between 30 and 100 degrees C and were determined with gas chromatograph-mass spectrometry. The extraction-temperature profiles of the 158 extracted pesticides were obtained to evaluate the effects of temperature on the extraction of pesticides. The pesticides were classified into four groups according to the shape of their extraction-temperature profiles. The line of demarcation between extractable pesticides and non-extractable pesticides could be drawn in the physical property diagram (a double logarithmic plot of their vapor pressure and partition coefficient between octanol and water). The plot also revealed relationships between classified extraction features and their physical properties. The new method for multi residue screening in which the analytes were categorized into sub-groups based on extraction temperature was developed. In order to evaluate the quantitivity of the developed method, the 45 pesticides were chosen among the pesticides that are typically monitored in waters. Linear response data for 40 of the 45 was obtained in the concentration range below 5 microg/l with correlation coefficients ranging between 0.979 and 0.999. The other five pesticides had poor responses. Relative standard deviations at the concentration of the lowest standard solution for each calibration curve of the pesticides ranged from 3.6 to 18%. The value of 0.01 microg/l in the limits of detection for 17 pesticides was achieved only under the approximate conditions for screening, not under the individually optimized conditions for each pesticide. Recoveries of tested pesticides in actual matrices were essentially in agreement with those obtained by solid-phase extraction.
通过评估温度对农药萃取的影响，证明了顶空固相微萃取（HS-SPME）在水样中农药测定方面的适用性。使用带有加热模块的自动化系统进行评估。基于气相色谱可检测的174种农药，根据其物理性质（蒸气压以及辛醇与水之间的分配系数）客观公正地进行了选择。在这174种农药中，158种（占测试农药的90%）在30至100摄氏度之间用聚丙烯酸酯涂层纤维进行萃取，并采用气相色谱 - 质谱联用仪进行测定。获取了这158种萃取农药的萃取温度曲线，以评估温度对农药萃取的影响。根据萃取温度曲线的形状，将农药分为四组。在物理性质图（其蒸气压与辛醇和水之间分配系数的双对数图）中，可以画出可萃取农药和不可萃取农药之间的分界线。该图还揭示了分类后的萃取特征与其物理性质之间的关系。开发了一种新的多残留筛查方法，其中分析物根据萃取温度被分类为子组。为了评估所开发方法的定量性，从通常在水中监测的农药中选择了45种农药。在浓度低于5微克/升的范围内，45种农药中的40种获得了线性响应数据，相关系数在0.979至0.999之间。其他五种农药的响应较差。每种农药校准曲线最低标准溶液浓度下的相对标准偏差在3.6%至18%之间。仅在近似筛查条件下，而非每种农药的单独优化条件下，才实现了17种农药0.01微克/升的检测限。实际基质中测试农药的回收率与固相萃取法获得的回收率基本一致。
