ISO 9198 pdf download.Paper, board and pulp — Determination of water-soluble sulfates
1 Scope
This International Standard specifies a method for the determination of water-soluble sulfates in all types of pulp, paper and board. The lower limit of the determination is 20 mg of sulfate ion per kilogram of dry sample.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 1 86:1 994, Paperandboard— Sampling to determine average quality. ISO 287:1 985, Paperandboard— Determination ofmoisture content— Oven-drying method. ISO 638:1 978, Pulps — Determination ofdrymattercontent. ISO 721 3:1 981 , Pulps — Sampling fortesting.
3 Term and definition
For the purposes of this International Standard, the following term and definition applies. 3.1 water-soluble sulfates ? in pulp, paper and board ? amount of sulfate ion that is extracted with water at 23 °C and determined under the conditions specified
4 Principle
Pieces of the sample are extracted with water at 23 °C in a disintegrator. An aliquot of the resulting suspension is used for determination of the sulfate ion content by ion chromatography.
5 Reagents
Use only reagents of recognized analytical quality and only water as specified in 5.1 . 5.1 Distilled water or deionized water, of conductivity less than 0,1 mS/m at 25 °C.
5.2 Sulfate stock solution, ? (SO 4 –2 ) = 1 000 mg/l. Dry a portion of potassium sulfate (K 2 SO 4 ) at 1 40 °C. Transfer 1 81 ,5 mg ? 2 mg thereof to a 1 00 ml volumetric flask, dissolve the salt and make up to the mark with water (5.1 ). Commercially available standard solutions can be used. 5.3 Sulfate matching solution Dilute the sulfate stock solution (5.2) with water (5.1 ) to a sulfate ion concentration of, for example, ? (SO 4 –2 ) = 1 0 mg/l. Do not use sulfate matching solutions that are more than 1 week old. 5.4 Other solutions, as specified in the instructions for the ion chromatograph.
6 Apparatus
6.1 Wet disintegrator, a high-speed mixer, capable of disintegrating the sample completely. 6.2 Ion chromatograph, having a pump, an injector loop of known volume, a column system suitable for the determination of sulfates and a conductivity detector. 6.3 Syringe, of a quality suitable for ion chromatography, of capacity 5 ml and having a filter of about 0,2 ?m pore width. 6.4 Tea strainer or similar device with a fine mesh screen, of stainless steel, to prevent fibres from clogging the syringe.
7 Sampling and preparation of sample
The procedure to be followed when sampling depends on the particular circumstances in each case. If the analysis is being made to evaluate a lot or a consignment of pulp, paper or board, the sample shall be taken in accordance with ISO 721 3 or ISO 1 86, as relevant. If the analysis is made on another type of sample, report the origin of the sample and, if possible, the sampling procedure. Since the amount of sulfates in the sample can be very low, take care not to contaminate it during sampling. Wear clean gloves at all times when handling the sample. Keep the sample protected, wrapped in aluminium foil or in plastic bags, until required for analysis. Select the sample portion for the analysis so that it is representative of the sample received.