8.5.3 Reaction10ml of the absorbent

8.5.3 Reaction10ml of the absorbent solution (8.3) are taken with a pipette and are moved in a 50ml bottle with 10 ml Acetylaceton solution (8.5.2.1) and 10 ml ammonium acetate-solution (8.5.2.2). The bottle is closed, shaken and warmed up for 15 minutes in a waterbath at 40ºC. The greenish-yellow solution is then cooled at ambient temperature, protected from the sunlight (about one hour). The optical density of this solution is determined with a wavelength of 412 nm by distilled water with a Spectrophotometer (6.4). A control is determined in parallel with distilled water and is taken into consideration with the calculation of the bottles value (9.2).Remark: After every test, the PE flasks are cleaned in a lab washer. Should this not be sufficient, it is advisable that the flasks are kept at 70ºC openly in a circulating air warm chamber for approximately 16 h.