BS ISO 26482:2010 pdf free.H ardmetals – Determination of lead and cadmium content.
BS ISO 26482 Add 15 ml of nitric acid (4.2) and 5 ml of hydrofluoric acid solution (4.3) and shake until exhaustion of NO, gas (red-brown color). Heat to complete dissociation. Control the heating temperature to prevent boiling of the solution. After dissociation of the sample, add 10 ml of perchloric acid (4.1) and keep heating until generation of a white gas of perchloric acid and until the final volume of sample is 5 ml to 10 ml.
Cool the platinum dish with the sample to room temperature, add 20 ml of nitric acid(1 + 1), cover with watch glass and heat. Add 20 ml of ammonium citrate solution (25 %) (4.4) and heat again. In the warm platinum dish, stirring with a PTFE rod, put (ittle by ltte) 40 ml of sodium hydroxide (25 %)1) to the time of colour change (yellow to pink)2).
Transfer the sample solution to a 250 ml glass beaker and cool it to room temperature.
Add 3 ml of potassium cyanide (10 %) (4.6) and adjust the pH of the solution to 9,2士0,2 with ammonium hydroxide (1 + 1) (4.7) or nitric acid (1 + 1) solution. Transfer the adjusted solution into a separation funnel by washing the beaker wall with distlled water. In case the pH of the solution that dissolves the sample is over 8,add 10 % potassium cyanide.
Put 20 ml of dithizone (0,02 %) (4.8) in the separation funnel and stir fully for 5 min.Stand until separation of the dithizone layer and water layer occurs. Transfer the lower layer of dithizone to a new beaker. Add 20 ml of dithizone (0,02 %) again and stir it fully for 5 min.Add 10 ml of dithizone (0,005 %) to the water layer of the separation funnel and wash by sirring fully for 5 min. Leave to stand to allow separation of the layers. Add the dithizone layer to the preceding dithizone layer.
Heat the solution at 60 °C to 80 °C in a warm bath until complete evaporation of chloroform occurs. Add 10 ml of nitric acid and 5 ml of perchloric acid to the dried glass beaker and insert a glass rod into the beaker. Cover with a watch glass and heat until generation of a white gas of perchloric acid. After the generation of a white gas of perchloric acid, dry and thicken it. After cooling it at normal temperature, transfer it to a 100 ml volumetric flask, dilute it with water and mix it.BS ISO 26482 pdf download.