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Quality control begins with sample collection and ends with the reporting of data. [4] AQC is achieved through laboratory control of analytical performance. Initial control of the complete system can be achieved through specification of laboratory services, instrumentation, glassware, reagents, solvents, and gases.
Mass spectrometry is a scientific technique for measuring the mass-to-charge ratio of ions. It is often coupled to chromatographic techniques such as gas-or liquid chromatography and has found widespread adoption in the fields of analytical chemistry and biochemistry where it can be used to identify and characterize small molecules and proteins ().
Laboratory quality control is designed to detect, reduce, and correct deficiencies in a laboratory's internal analytical process prior to the release of patient results, in order to improve the quality of the results reported by the laboratory.
C ratio: with a sample of known date, and a measurement of the value of N (the number of atoms of 14 C remaining in the sample), the carbon-dating equation allows the calculation of N 0 – the number of atoms of 14 C in the sample at the time the tree ring was formed – and hence the 14 C / 12 C ratio in the atmosphere at that time.
An LCR meter is a type of electronic test equipment used to measure the inductance (L), capacitance (C), and resistance (R) of an electronic component. [1] In the simpler versions of this instrument the impedance was measured internally and converted for display to the corresponding capacitance or inductance value.
The ion source converts and fragments the neutral sample molecules into gas-phase ions that are sent to the mass analyzer. While the mass analyzer applies the electric and magnetic fields to sort the ions by their masses, the detector measures and amplifies the ion current to calculate the abundances of each mass-resolved ion.
The results from AMS testing are in the form of ratios of 12 C, 13 C, and 14 C. These ratios are used to calculate F m, the "fraction modern", defined as = where R norm is the 14 C / 12 C ratio for the sample, after correcting for fractionation, and R modern is the standard 14 C / 12
Since most analytical instrumentation is comparative, it requires a sample of known composition (reference material) for accurate calibration. These reference materials are produced under stringent manufacturing procedures and differ from laboratory reagents in their certification and the traceability of the data provided.