multi EA 5000
Carbon analysis with the TOC module
93
Screw the screw cap with the septum on the top opening of the combustion tube. Con-
nect the condensation coil with the aid of a fork type clamp to the spherical joint on the
lateral outlet.
The oxygen gas supply (hose 3 of the basic module) is connected via a FAST connector
at the lateral outlet directly under the screw cap. The tube holder is used to fasten the
TOC combustion tube in the furnace.
Figure 59Tube holder for the TOC combustion tube
Sampling
Water samples are dosed directly into the TOC combustion tube via the injection port
with microliter syringes. A syringe with scale is used for manual dosing. For automatic
sampling via the autosampler, special microliter syringes are used. The syringes have
special dimensions and therefore have no scale. They are unsuitable for manual opera-
tion for this reason. The syringes have a gas connection for analyses in NPOC mode. The
injection volume is: 50 to 500 µl. Optimum measurement results are achieved when 50
to 100 % of the volume of the microliter syringe is used.
The injection port is equipped with temperature-resistant septums with a high penetra-
tion tolerance.
A proportion of the sample is dosed directly into the TIC reactor of the TOC module with
a microliter syringe with a scale to determine the inorganic carbon content (TIC). Only
manual dosing is permitted for this.
Measuring gas drying and
cleaning
For the analysis of water samples, the basic module is equipped with a condensation coil
made of glass. The condensation coil is connected to the TOC combustion tube via the
spherical joint. Connect hose 80 to the other end of the condensation coil via the the
FAST connector.
The measuring gas cools quickly in the condensation coil and the water vapor con-
denses. The mixture of measuring gas and water is transferred to the TIC reactor in the
detection module via hose 80.
