1. General Discussion
This method is designed to determine trace metals and metalloids in surface, ground, and drinking waters via inductively coupled plasma-mass spectrometry (ICP-MS). Although best suited for ambient or pristine freshwater matrices, this method can also be used to analyze wastewater, soils, sediments, sludge, and biological samples after appropriate digestion followed by dilution and cleanup to reduce matrix effects to a manageable level.1,2 Various cleanup techniques are available to reduce matrix interferences and concentrate the analytes of interest.3–7
For many analytes, the instrument detection limits (IDLs) are between 1 and 100 ng/L. The quadrupole-based ICP-MS may include collision cell technology (CCT) and dynamic reaction cell (DRC), which remove the need for mathematical interference correction for many elements. Additional data (Tables 3125:1 and 3125:2) demonstrate the performance for elements seriously affected by polyatomic interferences.8,9
The method is intended to be performance-based, so the elemental analyte list can be extended, new preparation techniques can be implemented, and other appropriate modifications can be made as technology evolves. Any modifications to the base method must be validated via suitable quality control standards. More sources of information on quality assurance and other aspects of ICP-MS analysis of metals are available.10–12
Ideally, the analysts who use this method will have experience using ICP-MS, interpreting spectral and matrix interferences, and implementing corrective procedures. Before generating data, analysts should demonstrate their proficiency in this method by successfully analyzing a performance evaluation sample for each matrix type.