Page 9 - 5_TOC in daily practice

Sum parameter – Total Organic Carbon

Kit for high-salt samples

SCA-130-504

Samples with high-salt loads generally are a While NaCl has a melting point of 801 °C, the
problem for TOC analysis. The problem is melting point of Na 2SO 4 is higher (888 °C).
less the conversion of organic compounds to The potassium salts of sulfuric acid also have
CO 2 than the effects of the salt on the a significantly higher melting point than those
catalyst. This leads to higher maintenance of hydrochloric acid. This has a positive effect
needs, as the salt can crystallize in the on the lifetime of the combustion tube.
combustion system.

In many applications for the instruments in Compound Melting point
the TOC-L and the TOC-4110/4200 series, NaCl 801°C
the kit for salt-containing samples is an
important component. It consists of a KCl 773°C
combustion tube of a special geometry and a 888°C
unique mixture of catalyst beads. Na 2SO 4
MgCl 2 708°C

CaCl 2 782°C
K 2SO 4 1.069°C
Tab. Melting point of different salts

Results indicate that the stability of the
catalyst is increased, and that up to 12 times
the number of samples can be measured
before the catalyst must be exchanged and
the instrument needs servicing.

■ Sample preparation
In this application, sample acidification is
carried out with sulfuric acid which is used to
modify the sample matrix.

Fig. Catalyst filling