检测方法LOD低于残留限度线要求，走头无路了怎么办？？

beiwei5du

在grab sampling中，当分析方法检测限（LOD、比如X）低于允许的残留限度线(比如3X),且没有方法可用，同时调整清洁取样方法（比如减少淋洗体积）不可得时，如何进行最终淋洗样的残留检测呢？？？附件提供了一种思路，使用dilution factor进行间接测定最终淋洗样中的实际残留限度。其基于的假设前提是：

Before we get to that, this type of calculation assumes that the residue being measured is more or less completely dissolved, solubilized or emulsified during the cleaning process, and that what happens in the rinsing process is that the dissolved, solubilized or emulsified active is removed by dilution with the successive rinses. If there is actually active on the surfaces that has not been dissolved, solubilized or emulsified during the cleaning process, then the active in the rinse solvent would be due both to a dilution factor and to additional active that is possibly removed from the surfaces. However, with proper design of the
cleaning process, this should not be an issue.

大家的看法是？？？？？

beiwei5du

同样通过这个原理，在separate rinse sampling检测中，保证倒数第二次penultimate rinse、final rinse和 separate rinse sampling操作和清洁溶剂组成体积相同的情况下，完全不进行该separate rinse sampling操作，而仅仅通过倒数第二次的penultimate rinse和final rinse的检测结果计算出dilution factor外推求出相应的separate sampling的检测结果，并与标准比对，判断设备的清洁是否合格。
大家如何看法？？？

stupid22273

浓缩、加标？？

beiwei5du

stupid22273 发表于 2017-9-14 18:54
浓缩、加标？？

通过稀释因子来做，我个人感觉这个有点理想化。@windy

windy

beiwei5du 发表于 2017-9-14 20:27
通过稀释因子来做，我个人感觉这个有点理想化。@windy

减少取样溶剂用量，可能会影响淋洗样品回收率，需要基于实验室回收率研究的数据，来评估减少取样溶剂用量是否合理。

cheng9gong

取样溶剂体积至少要能覆盖淋洗取样表面吧。
如果还不行，开发新方法，
开发难度或成本大，调安全因子，
如果还不行，规定排产顺序

bwybwybwy

cheng9gong 发表于 2017-9-14 21:16
取样溶剂体积至少要能覆盖淋洗取样表面吧。
如果还不行，开发新方法，
开发难度或成本大，调安全因子，

同意
之前有一个车间产品有此情况，最终只能规定排产顺序

小金库

谢谢分享