Instrument Description
The PE inductively coupled plasma–mass spectrometer (ICP-MS) torch box, interface, sample introduction and auto sampler components are enclosed in the ICP-MS radiological hood. The remainder of the instrument, such as vacuum chambers housing the mass filter, ion lens and detector, other electronics, vacuum systems and gauges, are located outside of the hood.
An argon plasma (ionized gas) is formed from the collision of argon atoms resulting in argon ions and electrons. The cooling and auxiliary gases (approximately 15 L/min) are used for the supply of argon. A Tesla coil is used to inject a critical excess of electrons during the time at which radio frequency (rf) energy is being applied through an rf generator. The formed argon plasma is self-sustaining as long as the generator provides sufficient power and the supply of argon is adequate. A liquid sample is introduced into the nebulizer, producing an aerosol. The aerosol is carried to the plasma and is ionized. Some ions are transferred to the quadrupole section of the instrument via a series of differentially pumped orifices (sampler and skimmer cones). The ions are passed through the lenses and mass filter and are detected at the electron multiplier.
Applications
The PE ICP-MS is used to measure trace and ultra-trace quantities of metallic components in various samples from radioactive or nonradioactive sources. It is used for elemental and isotopic analysis of solutions that may contain radionuclides, including plutonium and other alpha-emitting species.
Specifications
The Elan DRC II instrument combines the efficient ion generation characteristics of the inductively coupled plasma (ICP), the interference elimination properties of a dynamic reaction cell (DRC), and the axial field technology. It can be operated in standard or DRC mode. When operated in DRC mode, the background levels measured on peak are typically less than 1 count per second. The system consists of an ICP source, a vacuum and ion optics systems, a dynamic reaction cell, a quadrupole spectrometer, a dual mode detector, and a computer that controls the instrument. The quadruple mass spectrometer has a mass range of 5 to 270 amu, which may be scanned in milliseconds. The instrument allows the detection of ppb (µg/L) or even low ppt (ng/L) levels, depending on the sample preparation conditions. It is connected to an ESI auto sampler SC-micro DX, designed to be used with sample volumes of 0.5 and 1.0 mL.