EN 15040-2014 pdf download.Chemicals used for treatment of water intended for human consumption – Antiscalants for membranes – Phosphonic acids and salts.
5.1.3.1.1.1 Mix the contents of each container to be sampled by shaking the container, by rolling it or by rocking it from side to side, taking care not to damage the container or spill any of the liquid.
5.1.3.1.1.2 If the design of the container is such (for example, a narrow-necked bottle) that it is impracticable to use a sampling implement, take a sample by pounng after the contents have been thoroughly mixed. Otherwise, proceed as described in 5.1.3.1.1.3.
5.1 .3.1 .1 .3 Examine the surface of the liquid. If there are signs of surface contamination, take samples from the surface as described in 5.1.3.1.2; otherwise, take samples as described in 5.1.3.1.3.
5.1.3.1.2 Surface sampling
Take a sample using a suitable ladle, Lower the ladle into the liquid until the rim is just below the surface, so that the surface layer runs Into it, Withdraw the ladle just before it fills completely and allow any liquid adhering to the ladle to drain off. If necessary, repeat this operation so that, when the other selected containers have been sampled in a similar manner, the total volume of sample required for subsequent analysis is obtained.
5.1 .3.1.3 Bottom sampling
Take a sample using an open sampling tube, or a bottom-valve sampling tube, suited to the size of container and the viscosity of the liquid.
When using an open sampling tube, close it at the top and then lower the bottom end to the bottom of the container. Open the tube and move it rapidly so that the bottom of the tube traverses the bottom of the container before the tube Is filled. Close the tube, withdraw it from the container and allow any liquid adhering to the outside of the tube to drain off.
When using a bottom-valve sampling tube, close the valve before lowering the tube into the container and then proceed in a similar manner to that when using an open sampling tube.
5.1.3.2 Sampling from tanks and tankers
From each access point, take samples as follows:
a) from the surface of the liquid, using a ladle as described in 5.1.3.1.2;
b) from the bottom of the tank or tanker, using a sampling tube as described in 5.1.3.1.3 or using a specially designed bottom-sampling apparatus;
c) from one or more positions, depending on the overall depth, between the bottom and the surface using a weighted sampling can.
5.2.1.1 General
The determination of the phosphate content expressed in (P04) shall be determined in accordance with the Zimmermann method.
Phosphonic acids and salts are determined by means ot organic phosphate analysis. Phosphonic acids and salts have a strong C-P bond which is highly hydrolysis-stable. This bond shall be split by oxidation before the quantitative analysis of phosphate can be camed out.
5.2.1.2 Principle
Conversion of organic phosphate to orthophosphate by oxidation and reaction of orthophosphate with salts of molybdate in acid solution and in the presence of methaminophenol (a reducing agent) to a blue coloured complex. By the addition of citric acid the formation of silica molybdate is prevented (Zimmermann method).
5.2.1.3 Reagents
5.2.1.3.1 General
All the reagents shall be of a recognised analytical grade and the water used shall conform to grade 3 specified in
EN ISO 3696.
52.1.3.2 Hydrochloric acid, concentrated, density p = 1,18 9/mI,
5.2.1.3.3 Sulfuric acid, solution. c(HSO4) = 6 moth.
Add 500 ml of water to a 11 beaker. Cautiously add, with continuous stirring and cooling, 250 ml of sulfuric acid, p =184 9/mI. Mix well and allow the solution to Cool to room temperature.
5.2.1.3.4 Ammontum peroxodisulfate
5.2.1.3.5 Orthophosphate, standard stock solution
Dissolve 250.8 mg of Na2HPO4 with water in a 1 000 ml volumetric flask, dilute to the mark and mix.
5.2.1.3.6 Orthophosphate, standard solution
Dilute the standard stock solution (5.2.1.3.5) with water to 1+10.
5.2.1.3.7 Reducing agent
Add 20 g of methlaminophenol, 100 g of sodium pyrosulfite and 20 g of citric acid into a 1 000 ml volumetric flask. Dissolve with water, dilute to the mark and mix. Store the solution in a cool and dark place.EN 15040-2014 pdf download.