Finding the source of contamination in HPLC/ICP-MS can be difficult since these sources are not usually a problem with conventional HPLC. The reason for this is the ability of the ICP-MS (the detector) to see much lower levels than conventional HPLC detectors, such as UV.
Contamination sources include reagents, water, containers, filters/frits, sample vials and columns. To minimise contamination, as many metal and glass components as possible should be replaced with plastic.
Mobile phase contamination can be difficult to pinpoint and eliminate. The easiest way to identify contamination in the mobile phase is to analyse it directly by ICP-MS, without passing through the HPLC. If contamination is seen, then each mobile phase component should then be analysed separately to isolate the contamination source.
To resolve this problem, an alternate source of the contaminated component can be used. Alternately, a scavenger column can be placed between the HPLC pump and the injection valve to remove the contamination before sample is introduced.
If contamination resides in the HPLC itself, the manufacturer’s passivation/cleaning procedure should be followed. This usually involves flushing the system with a high concentration of acid.
To minimise contamination from the column, the column should be washed frequently, as recommended by the manufacturer. If the column is contaminated, the vendor’s column regeneration procedure should be followed.
Utilising these steps will allow users to determine sources of contamination and eliminate them.
PerkinElmer (www.perkinelmer.com)