ISO 6587:2021 pdf – Paper, board and pulps — Determination of conductivity of aqueous extracts.
1 Scope This document specifies a method for the determination of the conductivity of aqueous extracts of paper, board or pulp, these extracts having been prepared by a hot or cold method. The method is applicable to all kinds of paper, board and pulps, except for papers used for electrical purposes. For high purity papers used for electrical purposes, see method given in EN 60554-2. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 186, Paper and board — Sampling to determine average quality ISO 287, Paper and board — Determination of moisture content of a lot — Oven-drying method ISO 638-1, Paper, board, pulps and cellulosic nanomaterials — Determination of dry matter content by oven-drying method — Part 1: Materials in solid form ISO 7213, Pulps — Sampling for testing 3? Terms? and? definitions For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminology databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https:// www .org/ obp — IEC Electropedia: available at https:// www .electropedia .org/ 3.1 conductivity measure of the effect of the presence of dissolved substances in a solution to conduct electricity Note 1 to entry: Conductivity does not measure the same solution properties as either osmolality or osmolarity and does not produce equivalent results. Conductivity only measures those substances that produce ions and does not measure dissolved substances that do not produce ions. [SOURCE: ISO 18369-1:2017, 126.96.36.199]
5 Reagents 5.1 Distilled or deionized water Distilled or deionized water shall be used throughout the test. The conductivity of the water shall not exceed 0,2 mS/m after boiling and cooling as specified in 8.2.2. NOTE Usually, both distillation and deionization are required. Unless great care is exercised when distilling, and with the materials employed in the condenser and subsequent surfaces with which the condensed vapour would possibly come in contact, the distillate can fail to reach the required level of conductivity. When it is not possible to obtain water of the specified purity, water with a higher conductivity may be used, but the conductivity of the water used should be stated in the test report. 5.2 Potassium chloride, standard solutions Use potassium chloride (KCl) of recognized analytical reagent grade, powdered, or fine crystals. Dry for 2 h at 105 °C ± 2 °C and immediately prepare the following two solutions. 5.2.1 0,01 mol/l solution Dissolve 0,745 g of the potassium chloride in water having a conductivity not greater than 0,2 mS/m, and dilute to 1 000 ml. 5.2.2 0,001 mol/l solution Dilute 100 ml of the 0,01 mol/l solution (5.2.1) to 1 000 ml. Store the solutions in waxed glass bottles with ground glass stoppers. The conductivity values, in millisiemens per meter, of the two solutions, are given in Table 1.
7 Sampling and sample preparation 7.1 Sampling Sampling of paper or board shall be carried out in accordance with ISO 186. If the testing is done on another type of sample, report the origin of the sample, and if possible, the sampling procedure. Sampling of pulp shall be carried out in accordance with ISO 7213. If the testing is done on another type of sample, report the origin of the sample, and if possible, the sampling procedure. 7.2 Sample preparation Cut or tear the sample into pieces approximately 5 mm x 5 mm in size from portions that have not been touched by bare hands. Mix the pieces thoroughly. The sample shall not be touched at any time with bare hands. Clean protective gloves shall be worn at all times to protect the sample and the pieces prepared from it. Store the prepared samples in clean, covered containers. 7.3 Determination of dry matter content Determine the dry matter content in accordance with ISO 287 for paper or board and ISO 638-1 for pulp. 8 Procedure 8.1 Determination of cell constant Wash the measuring cell (see 6.3) several times with water (5.1), and then at least twice with the potassium chloride standard solution (5.2.1 or 5.2.2) the conductivity of which is nearest to that of the extract being measured. Measure the conductance or resistance of the cell by means of the conductivity meter or resistance bridge (6.3), with a fresh portion of the same potassium chloride standard solution.