The uncertaintyMANAGER facilities the user to calculate the measurement uncertainty for ICP-OES, ICP-MS and photometry. We have developed for all these analytical techniques an extensive library with individually adopted sample preparation steps.
ICP-OES, ICP-MS and photometry are like all other measurements a relative method. i.e. the signal of the sample is compared with the signal of a reference, whereas both measurements, sample and reference, are performed in the own laboratory. It is utterly crutial, that the compostion of the matrix for the sample and reference are identical. This has direct effects on the strategy of measuring and on the calculation of the measurement uncertainty.
Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), is an analytical technique used for the detection of trace metals. It is a type of emission spectroscopy that uses the inductively coupled plasma to produce excited atoms and ions that emit electromagnetic radiation at wavelengths characteristic of a particular element. The intensity of this emission is indicative of the concentration of the element within the sample.
The ICP-OES is composed of two parts. The ICP and the optical spectrometer. The ICP torch consists of 3 concentric quartz glass tubes. A water cooled coil of a radio frequency (RF) generator surrounds part of of the torch. Argon gas is typically used to create the plasma. When the torch is turned on, an intense magnetic field from the RF generator is turned on. The argon gas flowing through is ignited with a Tesla unit. The argon gas is ionized in this field and flows in a particular rotationally symmetrically pattern towards the magnetic field of the RF coil. A stable, high temperature plasma of about 7000K is then generated as the result of the inelastic collisions created between the neutral argon atoms and the charged particles.
A peristaltic pump delivers an aqueous or organic sample into a nebulizer where atomized and introduced directly inside the plasma flame. The sample immediately collides with the electrons and other charged ions in the plasma and is broken down into charged ions. The various molecules break up into their respective atoms which then lose electrons and recombine repeatedly in the plasma, giving off the characteristic wavelengths of the elements involved. Transfer lenses are then used to focus the emitted light on a diffraction grating where it is separated into its component radiation in the optical spectrometer. The light intensity is then measured with a photomultiplier tube at the specific wavelength for each element line involved.The intensity of each line is then compared to previous measured intensities of known concentrations of the element and its concentration is then computed by extrapolation along the calibration line.
A description of the possibilities for the ICP-MS will follow after the release of version 3.0.
The new possibilities to calculate the measurement uncertainty for photometry will be detailed after the release of version 3.0.
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