纯化水检测时效

微光fn1

水系统验证初期，第一阶段取样后除电导率及时测外，其他理化项目常温4小时检测，或2-8度存放24H检测，可以吗？需要做验证吗？有具体时间内检测的法规规定吗？

余默

可以，能做就做，不能做就算了，时间法规没有规定，如果要规定就做溶液稳定性

光风霁月

ChP和EP里面没有找到关于纯化水取样后检测时间的讨论或建议；


USP 1231 Water for Pharmaceutical Purposes (Officals as of 01-Dec-2021)中有（这里放原文自己看吧）：
1. 纯化水取样后化学测试的存放时间的讨论
    7.3 Storage and Hold Times for Chemical Tests
          Because of the homogeneous nature of chemical impurities in water, the storage requirements and impact of holding times are very practically determined, unlike the challenges of microbial impurities. In general, the chemical purity of high-purity water samples can only degrade over time, possibly generating a failed result of the sample that would have passed if it were tested immediately or on-line. The general fact is that the longer samples are stored, the greater the potential to be adversely affected by containers or conditions.
          For off-line chemical tests for waters, there are no compendial requirements for storage time and conditions. However, the general recommendation is to perform testing as soon as practical to avoid false adverse results. Where possible, store water samples in cool conditions and measure as quickly as practical. This reduces the chances that a water sample gets contaminated over time, and this would reduce unwarranted and unnecessary investigations of false positives.
     7.3.1 CONTAINERS
          When sampling water for off-line analysis, the selection and cleanliness of the container play a significant part in obtaining accurate data. For samples to be tested for chemical impurities according to <643> and <645> , the proper container should be one that does not contaminate the sample during the storage/hold time. For example, the use and preparation of glass containers could be very acceptable for storing samples for TOC testing, but some glass containers do leach ions over time (hours and days), and they can adversely affect a conductivity test by creating a false positive result—if the storage time is too long. Likewise, there are some polymer materials that can adversely affect the TOC chemical impurity in water. However, many polymer materials are very inert.
          In any case, cleanliness of the container is crucial because trace quantities of soaps and fingerprints will adversely affect the chemical purity of the water. Properly cleaned containers are acceptable because chemical impurities are easily rinsed away. Extensive chemical cleaning methods such as acid or caustic rinsing should never be needed. If they are needed, consider replacing the containers.
     7.3.2 STORAGE TIME AND CONDITIONS
           There are no specific recommendations for storage of samples for water analyses. If there is some trace interaction of the container and water, then generally colder and shorter storage times are better than warmer and longer storage times. Chemical dissolution and reactivity are usually enhanced by increased temperature. Furthermore, time is always an element because the water sample can only get worse in a container, and it never gets better with time.


2. 纯化水取样后微生物测试开展时间的建议
8.5.1 MICROBIAL ENUMERATION CONSIDERATIONS有关于微生物测试检测时间的推荐
           Consideration also should be given to the timeliness of microbial testing after sample collection. The number of detectable organisms in a sample collected in a sterile, scrupulously clean sample container will usually decrease as time passes. The organisms within the sample may die or adhere to the container walls, reducing the number that can be withdrawn from the sample for testing. The opposite effect can also occur if the sample container is not scrupulously clean and contains a low
concentration of nutrients that could promote microbial growth. Because the number of organisms in the water can change over time after sample collection, it is best to test the samples as soon as possible. If it is not possible to test the sample within 2 h of collection, the sample should be held at refrigerated temperatures (2°–8°) and tested within 24 h. In situations where even 24 h is not possible (such as when using off-site contract laboratories), it is particularly important to qualify the microbiological sample hold times and storage conditions to avoid significant changes in the microbial population during sample storage.