Calibration primary

Reliable quantification without calibration (primary technique)... 

Absolute frequency calibration is based on simultaneously recording the unknown spectrum and a spectrum of a suitable calibration species. The large number of calibration lines tabulated in atomic or molecular line atlases are in turn absolutely calibrated against a small number of even more accurately calibrated primary standard lines (Palmer, et al, 1981 Diddams, et ai, 2000). 

Calibrating the electrode presents a third complication since a standard with an accurately known activity for H+ needs to be used. Unfortunately, it is not possible to calculate rigorously the activity of a single ion. For this reason pH electrodes are calibrated using a standard buffer whose composition is chosen such that the defined pH is as close as possible to that given by equation 11.18. Table 11.6 gives pH values for several primary standard buffer solutions accepted by the National Institute of Standards and Technology. 

The submitters used a transformer purchased from the Franklin Transformer Company, Minneapolis, Minnesota, for 25-30. It was provided with taps so that secondary voltages of 5500, 6600, 7700, 8800, 9900, and 11,000 could be obtained. These transformers do not always deliver the rated voltage and hence should be calibrated by actual measurement. The checkers used a luminous tube transformer obtained from the Jefferson Electric Company, Bellwood, Illinois, Cat. No. 721-411. Cap. 825 VA. Primary 115 V.A.C. 60 cycles. Secondary 15,000 V. 60 M.A. Price 19.60. The variable transformer used to regulate the voltage should be rated at 7.5 amperes and may be a Varitran, Adjustavolt, or Variac. 

Full documented formal test runs at design and normal conditions. All instruments need to be calibrated for the runs and the documentation should include more than just the primary process variables of temperature, pressure, flow, and composition... 

The precision rotameter is a secondary calibration device. If it is to be used in place of a primary device such as a bubble meter, care must be taken to ensure that any introduced error will be minimal and noted. The precision rotameter may be used for calibrating the personal sampling pump in lieu of a bubble meter provided it is (a) Calibrated with an electronic bubble meter or a bubble meter, (b) Disassembled, cleaned as necessary, and recalibrated. It should be used with care to avoid dirt and dust contamination which may affect the flow, (c) Not used at substantially different temperature and/or pressure from those conditions present when the rotameter was calibrated against the primary source, (d) Used such that pressure drop across it is minimal. If altitude or temperature at the sampling site are substantially different from the calibration site, it is necessary to calibrate the precision rotameter at the sampling site where the same conditions are present. 

The so-called standard instrument is used for interpolation between the fixed points and for the calibration of other thermometers lower in the metrological hierarchy. The standard instrument in the moderate temperature range is a special platinum resistance probe, as it has to fulfill set requirements. It is important in all calibration that traceability to a primary normal, here the fixed-point ITS-90 scale, exists. 

Primary calibration standard A calibration standard based on direct measure of a reference value. 

Processes in this context means those series of related activities that turn inputs into outputs of added value. They include design, procurement, manufacture, packing, delivery, installation, maintenance, operations, disposal as well as the processes which serve these primary processes such as calibration, training, inspection, test, document control, etc. 

Anionic and neutral polymers are usually analyzed successfully on Syn-Chropak GPC columns because they have minimal interaction with the appropriate mobile-phase selection however, cationic polymers adsorb to these columns, often irreversibly. Mobile-phase selection for hydrophilic polymers is similar to that for proteins but the solubilities are of primary importance. Organic solvents can be added to the mobile phase to increase solubility. In polymer analysis, ionic strength and pH can change the shape of the solute from mostly linear to globular therefore, it is very important to use the same conditions during calibration and analysis of unknowns (8). Many mobile phases have been used, but 0.05-0.2 M sodium sulfate or sodium nitrate is common. 

The primary reason for die popularity of the Pople and DH style basis sets is the extensive calibration available. There have been so many calculations reported with these basis sets that it is possible to get a fairly good idea of the level of accuracy that can be attained with a given basis. This is of course a self-sustaining procedure, the more calculations that are reported with a given basis, tlie more popular it becomes, since the calibration set becomes larger and larger. 

Discussion. The formation of coloured compounds by coupling phenols with diazotised primary aromatic amines has long been recognised as a method of determining phenols, and procedures have been evolved whereby the phenol solution is titrated with a diazonium solution which has been calibrated against known concentrations of the phenol. The resultant reaction products are coloured, but many are only sparingly soluble in water and organic solvents and do not therefore lend themselves to colorimetric determination. 

The radicals formed by imimolecular rearrangement or fragmentation of the primary radicals arc often termed secondary radicals. Often the absolute rate constants for secondary radical formation are known or can be accurately determined. These reactions may then be used as radical clocks",R2° lo calibrate the absolute rate constants for the bimolecular reactions of the primary radicals (e.g. addition to monomers - see 3.4). However, care must be taken since the rate constants of some clock reactions (e.g. f-butoxy [3-scission21) are medium dependent (see 3.4.2.1.1). 

Because two laboratories were involved, there was a certain risk that this foreign contract laboratory in the cmcial calibration run would, despite cross-validation,26 come up with results for the QC standards that were at odds with those in the primary laboratory this would necessitate explanations. 

In a multi-year, multi-laboratory situation it is unlikely that the amount of primary standard (PS) will suffice to cover all requests. The next best thing is to calibrate a larger amount of lower-quality secondary standard (SS) against the PS, and to repeat the calibration at specified intervals until both the PS and the SS have been consumed. In this way, consistency can be upheld until a new lot of PS has been prepared and cross-validated against the previous one. In practice, a working standard will be locally calibrated against the SS and be used for the daily method calibration runs. (See Section 4.32.)... 

Results The raw data consisted of peak height ratios of signal internal standard, see data files VALIDl.dat (primary validation m - 0 repeats at every concentration), VALID2.dat (between-day variability), and VALID3. dat (combination of a single-day calibration with several repeats at 35 and 350 [ng/mlj in preparation of placing QC-sample concentration near these values). Fig. 4.29 shows the results of the back-calculation for all three files, for both the lin/lin and the log/log evaluations. Fig. 4.30 shows the pooled data from file VALID2.dat. 

---