Metrohm has reported how so-called hyphenated techniques in ion chromatography (IC) combine ultra-high sensitivity and separation power.
Hyphenated techniques combine the separation power of IC with the detection power of a mass spectrometer, providing the sensitivity and selectivity necessary for monitoring potentially toxic substances with lowest maximum contaminant levels.
Combining IC with an electrospray ionisation mass spectrometer (ESI-MS) or an inductively coupled plasma mass spectrometer (ICP-MS) solves even complex separation problems while achieving high sensitivity and selectivity.
These so-called hyphenated techniques provide valuable information for unambiguous peak identification and are less prone to matrix influences than IC with conductivity detection.
IC-MS determines bromate and perchlorate in drinking water.
Bromate, a potential carcinogen, is generated by the oxidation of bromide traces during water disinfection by ozonisation.
Current regulations for drinking water and mineral water stipulate limits of 10ppb and 3ppb, respectively.
As far as traces of perchlorate in drinking water are concerned, the US Environmental Protection Agency has developed an IC-ESI-MS method (EPA 332) with a detection limit in the sub-ppb range.
The advantage of this technique is that it can distinguish between different oxidation states and chemical forms of the three elements mentioned above.
As different valence states of an element have different properties, individual concentrations of element-containing species are, from the toxicological point of view, far more significant than total element concentrations.
