The determination of low levels of arsenic in chloride matrices by conventional ICP-MS is hampered by 40Ar35Cl+ interference, with detection limits generally at 0.1-2ppb
Arsenic is a natural contaminant in soils, water and the food chain, and can be toxic at low levels.
New environmental regulations have increased the need to perform accurate low-level arsenic determinations in environmental and biological matrices, many of which also contain significant amounts of chloride.
The determination of low levels of arsenic in chloride matrices by conventional ICP-MS is hampered by 40Ar35Cl+ interference, with detection limits generally at 0.1-2ppb.
A PerkinElmer application note describes and illustrates the use of the Elan DRC ICP-MS instrument for multi-element analysis in chloride matrices.
The Elan DRC significantly reduces the 40Ar35Cl+ background, so that arsenic can be routinely determined at levels below 100ppt.
In this application, the background reduction was accomplished using a 40% hydrogen, 60% argon reaction gas mixture in the reaction cell, with dynamic bandpass tuning parameters selected to eliminate unwanted secondary reaction products.
Automated software routines optimised reaction gas flow rate to maximise arsenic signal transmission while minimising the 40Ar35Cl+ background.
The analysis time was less than 60 seconds per sample.
For multi-element samples, the Elan DRC automatically switches between DRC mode and standard mode during the data acquisition, so the sample tube is only sampled once.
This ensures the best possible detection limits can be obtained in a multi-element run without sacrificing productivity.
