Interference Removal by ICP-CRC-MS
(inductively coupled plasma collision reaction cell mass spectrometry)
Using ICP-CRC-MS, sample aliquots are first introduced into a high energy radio frequency plasma the cause desolvation, atomization, and ionization. The generated ion beam then travels through a collision reaction cell (CRC) which preferentially reacts either with interfering ions of the same target mass to charge ratios or with the target analyte, which can then be differentiated from the initial interferences. This chamber operates in two modes (reactive mode and collision mode). In the reactive mode, the CRC contains a specific reactive gas which preferentially reacts with interfering ions of the same target mass to charge ratios or reacts the target analyte to produce a new molecule that has a different mass than the interferences. In the collision mode, the cell is filled with an un-reactive gas. Polyatomic interferences, due to their inherently larger size, are separated from the analyte of interest via kinetic energy discrimination (KED). The ions then exit the collision/reaction cell into an additional quadrupole (Q2), where detected ions are processed by a data handling system.
When operated in KED mode the CRC can act as a general interference removal tool which is appropriate for most elements. Certain elements, such as arsenic and selenium, can require alternate interference removal technologies (CRC operated in reaction mode) to properly remove interferences associated with calcium, chlorine, and other lighter elements. This fact necessitates a greater demand for experience of the analyst and laboratory to ensure the appropriate tools are used for the job.
Unfortunately, many laboratories using the ICP-CRC-MS platform do not take advantage of the different interference removal approaches or collect multiple data channels for each element which can equate to bias data. At Brooks Applied Labs we pride ourselves on collecting all pertinent data to make the most scientifically educated decisions ensuring our clients have the most defensible data possible.
To learn more about our innovative analytical methods and how they can benefit your projects, contact us today.