1、October 2016 English price group 20No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 13.030.40; 71.100.45!%199,9 %),
2、weighed to the nearest 1 mg, and previously dried at 250 C for 1 h, in water. Make up to 1 000 ml in a volumetric flask and mix. This solution is usable for one month. C.1.3.3 Polyvinyl alcohol (PVA) solution, (PVA) approximately 2 g/l. Dissolve 2 g of water soluble PVA in 1 l of water and heat to 6
3、0 C 70 C for better solubility. C.1.3.4 Silver nitrate solution, c(AgNO3) = 0,100 mol/l, standard volumetric solution. This solution is standardized as described hereafter: Transfer 10,00 ml of the sodium chloride solution (C.1.3.2) and 2 ml of nitric acid (C.1.3.1) and 5 ml of PVA solution (C.1.3.3
4、) into the titration vessel. Dilute to about 50 ml with water. Titrate the chloride with the silver nitrate solution (C.1.3.4) as described in C.1.6.3.2. The concentration of the silver nitrate solution, c(AgNO3), expressed in mol/l is given by the formula: 310(AgNO ) =58,443mVwhere m is the exact m
5、ass of sodium chloride, in g, used for the preparation of the solution (C.1.3.2); DIN EN 16811-1:2016-10EN 16811-1:2016 (E) 22 V is the volume of silver nitrate solution, in ml, used for the titration. Carry out three determinations and calculate the mean value of c(AgNO3). C.1.4 Apparatus Usual lab
6、oratory equipment and: C.1.4.1 Automatic titrator fitted with: silver electrode and double junction reference electrode (Ag/AgCl/KCl/KNO3); the KNO3solution in the outlet compartment shall be renewed each month; 20 ml burette; 150 ml titration vessel. This instrument should be able to operate under
7、the conditions shown in the next table: Table C.1 Conditions for titration Titration parameters Values Mode Potentiometric detection with dynamic equivalence point titration Increment near the equivalence point (EP) 25 l Signal drift after addition of titrant 15 mV/min Maximum waiting time after add
8、ition of titrant 40 sec Stirring yes C.1.4.2 Magnetic stirrer and stirring bars. C.1.5 Sampling and samples A test sample of about 500 g should be taken for analysis, ensuring that it is representative of the whole batch. C.1.6 Procedure C.1.6.1 Test portion Weigh, to the nearest 1 mg, about 10 g of
9、 the solid test sample. For brine the test portion is 30 g. C.1.6.2 Test solution Transfer the test portion (C.1.6.1) into a 100 ml volumetric flask and dissolve in water. Dilute to the mark with water and mix. C.1.6.3 Determination C.1.6.3.1 Apparatus setting Set all instrumental parameters of the titrator in accordance with the operating manual of the instruments manufacturer including the parameters cited in (C.1.4.1). DIN EN 16811-1:2016-10
