Calibration requirements

Procedures are required for the control and maintenance of inspection, measuring, and test equipment and to cover test software, not only for calibration. This section of the standard is often referred to as the calibration requirement but it goes far beyond mere calibration. In assessing compliance with section 4.11, there are at least 30 requirements to check (see the questionnaire at the end of this chapter) and calibration is only one of them. Figure 11.2 shows the processes needed to control, calibrate, and maintain inspection, measuring, and test equipment. The shaded boxes indicate interfaces with other processes. 

Calibration. Many approaches have been used to calibrate flow cytometric measurements. Including the comparison of flow and nonflow techniques (radiolabels, spectrofluorometry). In recent years, commercial standards have been introduced which are calibrated in fluorescein equivalents/particle (e.g., 3,000 or 500,000). With labeled ligands, calibration requires determining the relative quantum yield of the ligand compared to pure fluorescein and using the standards to analyze the amount bound on cells. Our ligands (fluorescein isothiocyanate derivatives) are typically 50% as fluorescent as fluorescein. 

Numerical Wide range of applications detailed spatial, temporal resolutions increased chemistry capabilities Extensive calibration requirements input data intensive (nodes, elements, time) require computer use and related skills Recommended for site specific applications... 

Electrical calibration has the advantage of being more flexible. It can afford s0 through equation 7.23 ifitisdone on the reference calorimeter proper. Flowever, it can also be performed on the initial or final state of the actual experiment leading to (e0 + ecl) or (e0 + ecf), respectively. Twenty or 30 years ago the electrical calibration required very expensive instrumentation that was not readily available except in very specialized places, such as the national standards laboratories. Although the very accurate electronic instrumentation that is available today at moderate prices may change the situation, most users of combustion calorimetry still prefer to calibrate their apparatus with benzoic acid. 

The calibration of a chemiluminescent analyzer using these standards is verified when both the nitrogen dioxide and nitric oxide channels respond similarly to charges from the (ylinder of diluted nitric oxide. Agreement with the response of the nitric oxide channel should also be obtained when the standard nitric oxide mixture is titrated with a previously established source of ozone. Chemiluminescent instruments have simplified monitoring of nitrogen oxides, but accurate calibration requires well-trained personnel. 

Perform calibration requirements identified in the manual or established by the validation team. 

Monitor calibration requires that the concentration of the contaminant in the air stream be accurately known. 

There is usually no calibration required. Thermal cyclers should be checked and calibrated by the manufacturer at least once every year. 

Internal standard (IS) calibration requires ratioing of an analytical signal to an IS which has very similar characteristics to that of the analyte of interest (an element which is similar to the analyte either in mass, ionisation potential or chemical behaviour). Quantitative analysis applying internal standardisation is the most popular calibration strategy in ICP-MS, as improvements in precision are obtained when the technique is appropriately used. Of course, the validity of this calibration method requires that one ensures a good selection of the correct internal standard. For this purpose it is possible to resort to chemometric methods [16]. 

Provide the calibration test sheet(s), applicable to the instrument under test, that should be used to record all test data necessary to satisfy the specified calibration requirements. 

A solution viscosity measurement is a hydrodynamic-thermodynamic technique, and the extent to which a polymer molecule increases the viscosity of a solvent depends on the nature of its interactions with that solvent (as well as on its own molecular weight). These interactions are characterized by the quantity a that appears in equation (3). The calibration of the method, using samples, of the same polymer having known molecular weights, in essence determines its value. The disadvantage of this calibration requirement is offset by the simplicity of the experimental measurements. 

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