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The instrument detection limit (IDL) is the analyte concentration that is required to produce a signal greater than three times the standard deviation of the noise level. This may be practically measured by analyzing 8 or more standards at the estimated IDL then calculating the standard deviation from the measured concentrations of those standards.
Concentration measurements are usually determined from a working curve after calibrating the instrument with standards of known concentration. The main advantages of the graphite furnace comparing to aspiration atomic absorption are the following: The detection limits for the graphite furnace fall in the ppb range for most elements
A calibration curve plot showing limit of detection (LOD), limit of quantification (LOQ), dynamic range, and limit of linearity (LOL).. In analytical chemistry, a calibration curve, also known as a standard curve, is a general method for determining the concentration of a substance in an unknown sample by comparing the unknown to a set of standard samples of known concentration. [1]
The triple quadrupole mass spectrometer allows for increased sensitivity and specificity yielding lower detection and quantitation limits. [8] For these reasons, employment of the TQMS is a vital asset in the fields of drug metabolism, pharmacokinetics, environmental studies, and biological analyses.
The detection limit of commercially available SIFT-MS instruments extends to the single digit pptv range. The instrument is an extension of the selected ion flow tube, SIFT, technique, which was first described in 1976 by Adams and Smith. [2]
In selective ion monitoring (SIM) certain ion fragments are entered into the instrument method and only those mass fragments are detected by the mass spectrometer. The advantages of SIM are that the detection limit is lower since the instrument is only looking at a small number of fragments (e.g. three fragments) during each scan.
NAA can detect up to 74 elements depending upon the experimental procedure, with minimum detection limits ranging from 0.1 to 1x10 6 ng g −1 depending on element under investigation. Heavier elements have larger nuclei, therefore they have a larger neutron capture cross-section and are more likely to be activated.
The original detection principle was realized in 1908 at the University of Manchester, [3] but it was not until the development of the Geiger–Müller tube in 1928 that the Geiger counter could be produced as a practical instrument. Since then, it has been very popular due to its robust sensing element and relatively low cost.