In principle, the ICP-IDMS method has the advantage that it
is not affected by matrix effects and is independent of the dissolved
organic substance, which cannot be assumed in all cases for the
conventional method. In addition, the isotope dilution technique
is an internal calibration method, whereas the conventional DOC
techniques must be calibrated by external standard solutions.
Recently, Oweczkin et al. published two papers, identical in
content, where the DOC concentration was determined by
inductively coupled plasma atomic emission spectrometry (ICPAES).
13,14 The calculated detection limits (2ó) were 0.03 and 1.09
mg L-1, respectively, for two different carbon emission lines.
However, this ICP-AES method was only applied for DOC
determinations in real samples at levels above 100 mg L-1.
Further experiments must, therefore, show the reliability of this
AES spectroscopic method for the low DOC concentration range
where the normal level of natural water systems lies.