Internal standardisation procedure

Relatively few studies have been made on the feasibility of quantitative FAB analysis. Riley et al. [217] have described a quantification procedure to monitor the paint additive Tinuvin 770 in two coating systems (acrylic melamine and a hydroxy ester melamine). Tinuvin 770 proved to be well suited for FAB analysis in coating extracts on glycerol basis using an internal standardisation procedure. Lay et al. [218] have developed a FAB-MS method for the quantitative analysis of plasticisers (DEHP, including any isomeric dioctyl phthalates) in baby PVC pacifiers that does not require sample extraction, clean-up, or chromatographic separation. A reference material, didecylphthalate (DDP), was added to a solution of the PVC sample in THF as an internal standard. Quantitation was based on the relative... 

There are currently no national or international standardised procedures for the determination of the activities of Po and Pb in waste gas stack emissions. Sampling... 

More national and international standardisation procedures for mercury porosimetry and the derivation of pore size distributions from adsorption isotherms are in preparation. Regarding the ueakness of the two-parameter BET model for surface area determination in addition the three-parameter BET equation or improved approximations (ref. 10) should be introduced. The more lengthy calculations can be easily managed using a computer. Competitive evaluation methods, like the method of Dubinin,... 

The most straightforward way to measure the effect of low temperatures on recovery is by means of a compression set or tension set test. Tests in compression are favoured and a method has been standardised internationally. The procedure is essentially the same as set measurements at normal or elevated temperatures and has been discussed in Chapter 10, Section 3.1. As the recovery of the rubber becomes more sluggish with reduction of temperature the dynamic loss tangent becomes larger and the resilience lower (see Chapter 9), and these parameters are sensitive measures of the effects of low temperatures. Procedures have not been standardized, but rebound resilience tests are inherently simple and quite commonly carried out as a function of temperature. It is found that resilience becomes a minimum when the rubber is in its most leathery state and rises again as the rubber becomes hard and brittle. 

The book collates the many standard methods, comments on their virtues and defects and considers procedures needed for both quality control and the generation of design data. The content owes much to the experience gained due to Rapra s position over many decades as an international centre for rubber research, as a test house with a history of developing test procedures and making a very significant contribution to national and international standardisation. The literature relating to the development and application of rubber test methods has also been reviewed. 

Atomic absorption analysis made available to the routine laboratory an analytical technique which initially was intended to produce considerable simplification of procedures for the analysis of aqueous, acidic or basic solutions, and thereby contribute to a reduction in costs. Numerous reviews show the worldwide application of this technique [15, 40, 77, 126—129, 137]. Nevertheless, some 10 years passed before atomic absorption became part of the international standardisation of analytical methods. At present, there are many standard methods being developed on the basis of atomic absorption [35, 67], Some, dealing with the determination of metals in lubricating oils, are already in use [35, 66], although the overwhelming majority, for example those dealing with the analysis of iron ores [67], are still being developed. The first indication of standardisation of atomic absorption methods for iron and steel analysis was seen in 1973 [8]. 

Quantification was based upon the method generally referred to as internal standardisation using, within each isomeric group, one C-labelled isomer as an internal standard. Inevitable differences in chromatographic retention and/or minor differences in ionisation efficiency, mass spectrometric fragmentation and ion masses monitored, lead to differences in sensitivities between the compounds to be determined and the corresponding C-labelled internal standards. These effects were accounted for in the final concentration calculation by the introduction of isomer specific relative sensitivity factors (RSF). Additional details on this procedure are described elsewhere [18,19]. 

Givens, D.I., Owen, E. and Adesogan, A.T. (2000) Current procedures, future requirements and the need for standardisation. In Forage Evaluation in Ruminant Nutrition, CAB International, Wallingford, UK, pp. 449M 74. 

Two synthetic internal standards are used (nor-DCA and nor-CA) to perform an external standardisation method. Calibration curves for each compound are built, starting from known amounts of standards ranging from 0.02 pg to 0.2 pg. BA standards are prepared and analysed as described in below in section 5.4.5.3 Analytical, Procedure . 

In the electrical field the International Electrotechnical Commission (IEC) performs the same function as ISO. The work of this body is of interest where rubbers are used in electrical insulation, etc. As regards electrical test methods for rubber, ISO and BSI have tended to adapt the basic procedures and principles standardised by IEC or to rely on the IEC standards. 

Outline procedures are given for using both mill and internal mixers which provide a very sound basis for obtaining reproducible mixes provided the detailed schedule for any particular mix is properly standardised and adhered to. This is all that can be hoped for considering that, in general, the results from laboratory mills and mixers are not identical with those obtained with full-sized factory equipment. 

A creep test is in essence very simple - a constant force is applied to the rubber and the change in deformation with time monitored - but detailed procedures were not standardised internationally until 1988 and there is still no general ASTM method. This reflects the relatively small amount of creep testing carried out on rubbers, which in turn is due to the relatively few rubber products where creep is a problem. This is in contrast to the situation with thermoplastics where creep performance is a prime engineering factor. However, for particular applications of rubber where creep is important, for example bridge bearings, a considerable amount of data has been generated. 

The Gehman test is also standardised in BS903 Part A1318 and ASTM D105319. The British Standard is identical to the international method but the ASTM has a rather different layout as it covers coated fabrics as well as rubbers and a single point procedure is added for routine inspection. It only specifies a step temperature change procedure. 

Article 8, paragraph 3 of the WFD requires that technical specifications and standardised methods for analysis and monitoring of water status be laid down in accordance with the procedure given in Article 21. Moreover, Annex V. 1.3.6 of the WFD states that the standards for monitoring of quality elements for physico-chemical parameters shall be any relevant CEN/ISO standards or such other national or international standards, which will ensure the provision of data of an equivalent scientific quality and comparability. 

For reproducible analyses and reliable control of polycyclic aromatic hydrocarbons (PAH) and related heterocyclic compounds, the availability of standardised analytical procedures is essential. When national or international regulations are issued or developed, standardised analytical methods are usually mandatory. 

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