Inductively coupled plasma (ICP) is an atomic spectroscopy technique that uses plasma to energize a sample into emitting light that can be analyzed for atomic composition. An important alternative is the use of mass spectrometry to analyze the ionized sample from the plasma. ICP mass spectrometry (ICP-MS) is an extremely sensitive technique for atomic spectroscopy. Even within the ICP-MS market, instruments that use magnetic sector mass analyzers are considerably more sensitive than the more common quadrupole detectors. Detection limits in the part per quadrillion range are achievable. Additionally, these instruments are not only sensitive, but they generally are very precise in their mass measurements, allowing them to eliminate interferences that might stymie less discriminating instruments. For this reason, magnetic sector instruments are sometimes called high-resolution ICP-MS or HR-ICP-MS. Although magnetic sector instruments can cost several times more than a quadrupole ICP-MS, the performance capabilities make them invaluable for particularly demanding applications. Sensitivity comes into play for applications in the semiconductor industry, where tiny concentrations of contaminants in water and other process chemicals can even affect wafer processing. Similarly, many pharmaceutical applications require ultrapure water. Apart from their sensitivity, magnetic sector instruments are also well-suited for determining the relative abundance of different isotopes present in a sample. Isotopic ratio measurements are typically the province of academic research, where such methods can be used for geochemistry and geochronology. Although standard ICP-MS requires aqueous samples, the related technique of glow discharge MS (GD-MS) is more readily applied to geological samples. Alternatively, many ICP-MS systems have laser ablation options for solid samples. Other important isotopic ratio measurements are made in the biological sciences and even food analysis. Although routine environmental analysis is seldom done with HR-ICP-MS, environmental scientists can use isotopic ratios to analyze contaminants and infer their origin. Thermo Fisher Scientific has cemented its position as the world leader in magnetic sector ICP-MS. Most recently, Thermo acquired GV Instruments (see IBO 7/31/06), which had been a leader in magnetic sector MS for isotopic ratio determination and noble gas analysis. GV’s Platform XS ICP-MS has now been added to Thermo’s product line. The only other significant player is Nu Instruments, which focuses on mammoth multicollector high-resolution instruments mainly for academic applications in geochemistry. Mass Spectrometry Instruments (MSI) is involved only in magnetic sector GD-MS. IBO estimates that the total market for magnetic sector ICP-MS and GD-MS was $23 million in 2006.