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发表于 2013-6-3 16:10:25
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bigdogpolice 发表于 2013-6-3 15:52 
纯化水罐的水质并不能整个系统的水质,这个系统的质量有关系,比如焊接的质量、系统的密闭性、管道的材质等 ...
不是说不想做,也知道做是安全的,无奈买不到无氮硫酸。
你说的稀释理论应该不存在,由于各成分在水中都是溶解的,经过循环后,水质(除微生物外,因为它和取样点有关)可以认为是均一的,即使按你所说,总回也是最差的,是否有代表性?
至于说焊接、密封、材质等都属于OQ的一部分,PQ三个阶段完成后,水系统已经运行一年以上了,即使初始有脱落也脱没了。而且USP1231中并没有明确要与实验室检验相结合,估计是一些翻译的问题。
Sampling for chemical analyses is also done for in-process control and for quality control purposes. However, unlike microbial analyses, chemical analyses can be and often are performed using on-line instrumentation. Such on-line testing has unequivocal in-process control purposes because it is not performed on the water delivered from the system. However, unlike microbial attributes, chemical attributes are usually not significantly degraded by hoses. Therefore, through verification testing, it may be possible to show that the chemical attributes detected by the on-line instrumentation (in-process testing) are equivalent to those detected at the ends of the use point hoses (quality control testing). This again creates a single sample and mixed data use scenario. It is far better to operate the instrumentation in a continuous mode, generating large volumes of in-process data, but only using a defined small sampling of that data for QC purposes. Examples of acceptable approaches include using highest values for a given period, highest time-weighted average for a given period (from fixed or rolling sub-periods), or values at a fixed daily time. Each approach has advantages and disadvantages relative to calculation complexity and reflection of continuous quality, so the user must decide which approach is most suitable or justifiable.
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