Fastner Jutta, Codd Geoffrey A, Metcalf James S, Woitke Peter, Wiedner Claudia, Utkilen Hans
Technical University Berlin, Fränklinstr. 29, 10587 Berlin, Germany.
Anal Bioanal Chem. 2002 Oct;374(3):437-44. doi: 10.1007/s00216-002-1520-7. Epub 2002 Sep 11.
The comparability of current microcystin analysis methods has been evaluated in an international intercomparison exercise. The focus was on the analysis of microcystins by high-performance liquid chromatography coupled with ultraviolet or photodiode-array detection (HPLC-PDA/UV), currently the most widespread method for microcystin analysis, but the exercise was open for other methods such as enzyme-linked immunosorbent assay (ELISA), protein phosphatase inhibition assay (PPA) and high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS).Thirty-one laboratories from 13 countries participated in the study. For a microcystin-LR (MC-LR) standard solution (S1) of undisclosed quantity, and for a field sample (S3) from a natural cyanobacterial bloom, repeatabilities between 4 and 15% and reproducibilities between 24 and 49% were obtained. No significant differences between single methods were found for S1 and S3, except for a significantly higher repeatability value of ELISA for S1. However, the analysis of microcystins in the field sample (S3) by HPLC-PDA/UV was significantly more variable than for the standard solution (S1). Both the extraction and the analysis of the microcystins appeared to contribute to this variability. It is concluded that standard MC-LR (S1) can be measured with adequate precision by all participating laboratories independently of the method used. With respect to the different methods used the results for the field sample can also be regarded as satisfactory, but clearly showed the need for improvement by standardisation between laboratories. Furthermore, quantification with in-house standards compared to quantification using the supplied MC-LR standard indicated that routine microcystin analysis in laboratories may be also influenced by the variability of available standards, emphasising the need for the production of certified reference materials (CRM).
在一项国际比对实验中对当前微囊藻毒素分析方法的可比性进行了评估。重点是通过高效液相色谱结合紫外或光电二极管阵列检测（HPLC-PDA/UV）来分析微囊藻毒素，这是目前微囊藻毒素分析中最广泛使用的方法，但该实验也对其他方法开放，如酶联免疫吸附测定（ELISA）、蛋白磷酸酶抑制测定（PPA）和高效液相色谱结合质谱（HPLC-MS）。来自13个国家的31个实验室参与了该研究。对于未公开数量的微囊藻毒素-LR（MC-LR）标准溶液（S1）以及来自天然蓝藻水华的现场样品（S3），获得了4%至15%的重复性和24%至49%的再现性。对于S1和S3，单一方法之间未发现显著差异，但S1的ELISA重复性值明显更高。然而，通过HPLC-PDA/UV对现场样品（S3）中的微囊藻毒素进行分析时，其变异性明显高于标准溶液（S1）。微囊藻毒素的提取和分析似乎都导致了这种变异性。得出的结论是，所有参与实验室都可以独立于所使用的方法以足够的精度测量标准MC-LR（S1）。就所使用的不同方法而言，现场样品的结果也可被视为令人满意，但清楚地表明需要通过实验室间的标准化来改进。此外，与使用提供的MC-LR标准进行定量相比，使用内部标准进行定量表明实验室中的常规微囊藻毒素分析也可能受到可用标准变异性的影响，强调了生产有证标准物质（CRM）的必要性。
