Turner Andrew D, Dhanji-Rapkova Monika, Baker Clothilde, Algoet Myriam
J AOAC Int. 2014 Mar-Apr;97(2):492-7. doi: 10.5740/jaoacint.13-381.
AOAC Official Method 2005.06 precolumn oxidation LC-fluorescence detection method has been used for many years for the detection and quantitation of paralytic shellfish poisoning (PSP) toxins in bivalve molluscs. After extensive single- and multiple-laboratory validation, the method has been slowly gaining acceptance worldwide as a useful and practical tool for official control testing. In Great Britain, the method has become routine since 2008, with no requirement since then for reverting back to the bioassay reference method. Although the method has been refined to be semiautomated, faster, and more reproducible, the quantitation step can be complex and time-consuming. An alternative approach was developed to utilize the qualitative screening results for generating a semiquantitative results assessment. Data obtained over 5 years enabled the comparison of semiquantitative and fully quantitative PSP results in over 15 000 shellfish samples comprising eight different species showed that the semiquantitative approach resulted in over-estimated paralytic shellfish toxin levels by an average factor close to two in comparison with the fully quantified levels. No temporal trends were observed in the data or relating to species type, with the exception of surf clams. The comparison suggested a semiquantitative threshold of 800 microg saxitoxin (STX) eq/kg should provide a safe limit for the determination of samples to be forwarded to full quantitation. However, the decision was taken to halve this limit to include an additional safety factor of 2, resulting in the use of a semiquantitative threshold of 400 microg STX eq/kg. Implementation of the semiquantitative method into routine testing would result in a significant reduction in the numbers of samples requiring quantitation and have a positive impact on the overall turnaround of reported PSP results. The refined method would be appropriate for any monitoring laboratory faced with high throughput requirements.
AOAC官方方法2005.06柱前氧化液相色谱 - 荧光检测法多年来一直用于双壳贝类中麻痹性贝类毒素（PSP）的检测和定量。经过广泛的单实验室和多实验室验证，该方法作为官方控制检测的一种有用且实用的工具，正在全球范围内逐渐被接受。在英国，自2008年以来该方法已成为常规方法，此后无需再采用生物测定参考方法。尽管该方法已改进为半自动、更快且更具可重复性，但定量步骤可能复杂且耗时。开发了一种替代方法，利用定性筛选结果进行半定量结果评估。5年期间获得的数据能够比较超过15000个包含8个不同物种的贝类样品的半定量和完全定量PSP结果，结果表明，与完全定量水平相比，半定量方法导致麻痹性贝类毒素水平平均高估近两倍。除了 surf clams外，未观察到数据中的时间趋势或与物种类型相关的趋势。比较结果表明，800微克石房蛤毒素（STX）当量/千克的半定量阈值应为确定需要进行完全定量的样品提供安全限值。然而，决定将此限值减半，以纳入额外的安全系数2，从而采用400微克STX当量/千克的半定量阈值。将半定量方法应用于常规检测将导致需要定量的样品数量显著减少，并对报告的PSP结果的总体周转产生积极影响。改进后的方法适用于任何面临高通量要求的监测实验室。
