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USP1231《制藥用水》規(guī)定了水質(zhì)檢驗(yàn)樣品存放時(shí)間和存放條件的相關(guān)要求，包括化學(xué)測(cè)試樣品和微生物檢驗(yàn)的樣品。概述如下：

Sampling Hold Times for Chemical Tests

化學(xué)測(cè)試樣品存放時(shí)間

Basically it is advisable to conduct chemical tests immediately after extracting samples, since impurities may dissolve in water once the sample has been bottled. These impurities may be caused by contamination from ambient air or by the walls of the sample container (“leach-out”). In both cases the longer the samples are stored, the greater the potential to be adversely impacted by containers or conditions, in the worst case creating a false positive result. The proper container should be one that does not contaminate the sample during storage/hold time, eliminating the possibility that leach-out impacts certain parameter, i.e. glass bottles for the TOC assessment, plastic bottles for the measuring of the conductivity. Irrespective of the material of the container, where possible the sample should be stored cool and only for a short time in order to obtain representative results.

基本上，在取完樣之后立即進(jìn)行化學(xué)檢驗(yàn)是合適的，因?yàn)橐坏悠费b入瓶子里之后雜質(zhì)可能會(huì)溶入水里。這些雜質(zhì)可能來(lái)源于環(huán)境中的空氣或者取樣容器的內(nèi)壁（浸出）。樣品存放越長(zhǎng)，受容器或條件不利影響的可能性越大，甚至導(dǎo)致假陽(yáng)性結(jié)果。選擇合適的容器使在存放過(guò)程中不污染樣品，排除浸出影響某一參數(shù)可能性，如使用玻璃瓶進(jìn)行TOC檢驗(yàn)、使用塑料瓶進(jìn)行電導(dǎo)率測(cè)試等。除了容器材質(zhì)的影響，適當(dāng)時(shí)，樣品應(yīng)被存放于陰涼條件下，并僅存放較短時(shí)間，以獲取有代表性的結(jié)果。

Sampling Hold Times for Microbiology

微生物檢驗(yàn)樣品存放時(shí)間

As in the case of the chemical tests, the new guideline adds advice on hold times for the micro-biological examination of water (chapter 8.5.1). It points out that the results of incubation during a lengthy holding time may go either way, even unintentionally improving the sample or being detrimental to it. Germs found in very clean samples (and containers) will tend to decrease over time, whereas those in an impure sample are prone to increase. Thus, the risk of false positive/negative results increases during a lengthy holding time. Therefore, the sample should be cooled during a holding time of over two hours. Incubation should take place within 24 hours. 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.

正如化學(xué)檢驗(yàn)一樣，該新指南提供了水質(zhì)微生物檢驗(yàn)保存時(shí)間的建議（章節(jié)8.5.1）。它指出樣品保存期間培養(yǎng)的結(jié)果可能會(huì)變化，或，在非常干凈的樣品（或容器）中發(fā)現(xiàn)的細(xì)菌將會(huì)隨著時(shí)間不斷減少，而在一個(gè)不干凈的樣品中，則會(huì)不斷增加。這樣，在保存一段時(shí)間后得到假陽(yáng)性/假陰性結(jié)果的風(fēng)險(xiǎn)將會(huì)增加。因此，樣品保存時(shí)間超過(guò)2個(gè)小時(shí)的，應(yīng)給放置于陰涼處。培養(yǎng)應(yīng)在24小時(shí)內(nèi)進(jìn)行。當(dāng)24小時(shí)內(nèi)培養(yǎng)都沒(méi)辦法做到時(shí)（例如當(dāng)使用工廠外的合同實(shí)驗(yàn)室時(shí)），微生物樣品保存時(shí)間和保存條件應(yīng)進(jìn)行確認(rèn)以避免樣品保存期間微生物水平發(fā)現(xiàn)明顯變化顯得尤其重要。