Digestion On C.o.d. Determination - Selecta DQO 6 Manual De Instrucciones

MANUAL DE INSTRUCCIONES 80158 REV D OCT/2019 (Sujetas a modificaciones sin previo aviso) Pag.: 32
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Digestion on C.O.D. determination

• Add 5.0ml of potasic dichromat and some glass balloons to regulate ebullition
to the sample and it is homogenized carefully.
• Add slowly 15ml. of silver sulphate - sulphuric acid, shaking the tube carefully
with a circular movement, cooling down with cool water of the tap or an ice bath,
in order to avoid any loss of organically volatile substances.
• Place the tubes dully prepared into the rack tubes holder on their support.
With the help of a rack, insert it into the heating block.
• Join on each tube a refrigerant in order to fit correctly the polished gaskets.
• Program the operating temperature (170-200ºC) and the length time (around
2 hours) of the back flowing into the temperature regulator and RAT time.
• Press on «START» and at this moment the metallic block will heat where
the tubes are placed. This will be done in a progressive way and when the
preselectionated temperature is reached, the time of back flowing will be counted.
• Once the time is finished, the heating in the metallic block stops automatically
and an acoustic sound is heard. At this moment, you should press on «STOP»
in order to finish the process.
• Let the tubes cool down for a while and clean the projections that have been
produced in the inner wall of the refrigerants into the sample recipient with a
little volume of distilled water.
• Separate the refrigerants from the tubes, and the tubes are extracted with the
help of the rack, that is placed on the support. The sample is diluted with 75 ml.
of distilled water and it is cooled down at ambient temperature.
J
.P. SELECTA s.a.u. Ctra. NII Km 585.1 Abrera 08630 (Barcelona) España Tel 34 93 770 08 77 Fax 34 93 770 23 62
e-mail: selecta@jpselecta.es - website: http://www.jpselecta.es