Strategy formulation reference standards

In many instances, the analytical reference standard will be readily available from one or more commercial sources but this is not always the case. Certified reference materials (Section 2.2.2, not natural matrix CRMs but calibration solutions that are solutions of a reference standard at a certified concentration in a clean solvent) must be prepared and characterized in accordance with the strict guidelines in ISO Guide 34-2000 (ILAC 2000). The reference standard may also be supplied by the chent and this is often the case when working with proprietary compounds in development. If neither of these two options exist, the standard must be synthesized or in some instances extracted from a natural product or commercial formulation and then purified. The requirements for obtaining a certificate of analysis (Section 9.4.4c) or other documentation that establishes the identity and purity of the analyte are discussed in Section 2.2.2 and also below in 9.4.4c, but the amount of standard available is also an important factor in terms of formulating a strategy for the... 

Special attention has been dedicated to the study of the basis set superposition error (BSSE). The SCF-Ml algorithm which excludes the BSSE from the SCF function was employed. A multi configuration version of it, particularly suited to study proton transfer effects, has been formulated. The use of these techniques has led to binding energy values which show a better stability against variation of the basis set, when compared with standard SCF results. For a more complete evaluation of the advantages of the a priori strategy to avoid BSSE see references [47-50], where applications to the study of the water properties are reported, and reference [51], where the Spin Coupled Valence Bond calculations for the He-LiH system are presented. 

The reference system of analytical chemistry comprises terms, standards, scales and the measuring system. The system allows one to formulate analytical problems and to develop analytical strategies. 

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