本文件规定了一种测定pH值的方法，该pH值由可通过冷水从纸、纸板或纸浆样品中提取的电解质定义。 本文件适用于所有类型的纸、纸板和纸浆。 当可提取的离子材料的量接近零时，如在高度纯化的纸浆的情况下，由于在对含有少量电解材料的水进行pH测量时遇到困难，该方法的精度变差。 由于本文中的提取是用蒸馏水或去离子水进行的，因此测量的pH值有时可以不同于(例如对于完全漂白的纸浆)在磨机工艺条件下测量的pH值，其中使用各种类型的工艺水，例如含有电解质的化学处理的河水。在这种情况下，ISO？29681可以替代地使用，因为它特别适用于来自原始纤维的漂白纸浆和具有低离子强度的纸浆样品，对于这些纸浆样品，pH值给出的与磨机条件相关的结果比用本文件获得的结果更真实。 对于用于电气目的的纤维素纸，使用的方法可以是IEC中给出的方法？60554？2[5].

This document specifies a method for the determination of the pH-value defined by the electrolytes extractable by cold water from a sample of paper, board or pulp. This document is applicable to all types of paper, board and pulp. As the quantity of extractable ionic material approaches zero, as in the case of highly purified pulps, the precision of the method becomes poor because of the difficulties encountered in making pH measurements on water containing little electrolytic material. Since the extraction in this document is performed with distilled or deionised water, the pH-value measured can sometimes be different (e.g. for fully bleached pulp) from the pH-value measured under mill process conditions, in which various types of process waters, such as chemically treated river water containing electrolytes, are used. In such cases, ISO？29681 can be used instead, as it is specifically applicable to bleached pulps from virgin fibres and to pulp samples having a low ionic strength for which the pH value gives more realistic results related to mill conditions than those obtained with this document. For cellulosic papers used for electrical purposes, the method used can be that given in IEC？60554？2^[5].