van Leeuwen S P J, Swart C P, van der Veen I, de Boer J
VU University - Institute for Environmental Studies (IVM), De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
J Chromatogr A. 2009 Jan 16;1216(3):401-9. doi: 10.1016/j.chroma.2008.11.029. Epub 2008 Nov 18.
The 2nd international interlaboratory study (ILS) on perfluorinated compounds (PFCs) in environmental samples was organized to assess the performance of 21 North American and European laboratories on the analysis of PFCs in water and fish. A study protocol was provided to assess accuracy, precision, matrix effects and to study the use of in-house standards. The participants used shared native and mass-labelled standards that were provided for this study to quantify the PFC concentrations in the samples. Matrix effects in the determination of PFCs can be considerable and can decrease the sensitivity, the accuracy and internal standard recoveries. Therefore, two quantification methods were evaluated by all laboratories: standard addition quantification (SAQ) and solvent-based calibration curve quantification (SBCCQ; using mass-labelled internal standards (IS)). The between laboratory reproducibility (i.e. coefficient of variance) was smaller for the SBCCQ results (except for PFBS and PFHxS for which no mass-labelled analogues were available) compared to those obtained by the SAQ method. The within laboratory precision of individual laboratories is good (mean for all PFCs in water 12% and 6.8% in fish). The good performance is partially attributable to the use of well-defined native- and mass-labelled standards. Therefore, the SBCCQ method is recommended. The results show that analytical methods for PFCs in water and fish have improved considerably. Critical steps identified in this study are (i) the use of well-defined native standards for quantification, (ii) the use of mass-labelled internal standards (preferably one for each target compound) and (iii) minimization of matrix effects by a better clean up.
第二届环境样品中全氟化合物（PFCs）国际实验室间研究（ILS）旨在评估21家北美和欧洲实验室对水和鱼类中PFCs的分析性能。提供了一项研究方案，以评估准确性、精密度、基质效应并研究内部标准的使用。参与者使用为本研究提供的共享天然和质量标记标准来量化样品中的PFC浓度。测定PFCs时的基质效应可能相当大，会降低灵敏度、准确性和内标回收率。因此，所有实验室评估了两种定量方法：标准加入定量法（SAQ）和基于溶剂的校准曲线定量法（SBCCQ；使用质量标记内标（IS））。与SAQ方法获得的结果相比，SBCCQ结果的实验室间再现性（即变异系数）较小（除了没有质量标记类似物的全氟丁烷磺酸和全氟己烷磺酸）。各个实验室的实验室内精密度良好（水中所有PFCs的平均值为12%，鱼类中为6.8%）。良好的性能部分归因于使用了定义明确的天然和质量标记标准。因此，推荐使用SBCCQ方法。结果表明，水和鱼类中PFCs的分析方法有了显著改进。本研究确定的关键步骤包括：（i）使用定义明确的天然标准进行定量；（ii）使用质量标记内标（最好每种目标化合物一个）；（iii）通过更好的净化使基质效应最小化。
