Assessment of Results

The values given in Table XI (Section III,A,1) for the A-methylpiperidine equilibria show that dipole-moment measurements with the associated assumptions consistently give rise to lower estimates of — AG° than those from other methods. 

In several other series, conclusions were reached that are now known to be seriously in error. These include 1,2-dialkylhexahydropyridazines (Section III,C,2), 3-alkyltetrahydro-l,3-oxazines (Section III,D,1), 3-alkyltetra-hydro-l,3-thiazines (Section II1,D,2), and trialkylhexahydro-l,3,5-triazines (Section III,G,5). 

However, in many other series results have been obtained that are compatible with those from other methods and that gave the dipole-moment method an appearance of general reliability now known to be unjustified. Such compatible results include spiropiperidines (Section III,A,4), tropanes (Section III,B,4), 2-alkyltetrahydro-l,2-oxazines (Section III,C,2), perhydro-pyrido[l,2-c][l,3]oxazines (Section III,D,IX perhydropyrido[l,2-c][l,3]thi-azines (Section III,D,2), dialkylhexahydropyrimidines and perhydropyrido-[l,2-c]pyrimidines (Section III,D,3), 5-alkyldihydro-l,3,5-dithiazines (Section III,G,3), 3,5-dialkyltetrahydro-l,3,5-thiadiazines (Section III,G,4) and, in part, l,2,4,5-tetraalkylhexahydro-l,2,4,5-tetrazines (Section III,H,4) as well as piperidines, tetrahydro-l,3-oxazines, and tetrahydro-l,3-thiazines containing an N-H group. 

There are many possible sources of error in the calculation of equilibrium from dipole moments. It is difficult to calculate accurately the moments of model compounds. As has been pointed out,124 the carbon skeleton itself contributes to the moment, as shown by the different dipole moments of ethyl bromide (2.069 D) and n-hexyl bromide (2.156 D) and of axial and equatorial fluorocyclohexane (1.81 D and 2.11 D, respectively). For nonsym-metrical molecules in general, the estimation of the precise direction of a dipole moment is subject to considerable error. 

The dipole moments of N-axial and N-equatorial methylpiperidine may not be equal because of differing hybridization changes at nitrogen. 

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Factors may be classified as quantitative when they take particular values, e.g. concentration or temperature, or qualitative when their presence or absence is of interest. As mentioned previously, for an LC-MS experiment the factors could include the composition of the mobile phase employed, its pH and flow rate [3], the nature and concentration of any mobile-phase additive, e.g. buffer or ion-pair reagent, the make-up of the solution in which the sample is injected [4], the ionization technique, spray voltage for electrospray, nebulizer temperature for APCI, nebulizing gas pressure, mass spectrometer source temperature, cone voltage in the mass spectrometer source, and the nature and pressure of gas in the collision cell if MS-MS is employed. For quantification, the assessment of results is likely to be on the basis of the selectivity and sensitivity of the analysis, i.e. the chromatographic separation and the maximum production of molecular species or product ions if MS-MS is employed. 

Evershed, R. P., Dudd, S. N., Copley, M. S. and Mukherjee, A. J. (2003b) Identification of animal fats via compound specific 813C values of individual fatty acids assessments of results for reference fats and lipid extracts of archaeological pottery vessels. In Documenta Praehistorica, XXIX 9th Neolithic Studies (Ed. Budja, M.), Ljubljana, pp. 73 96. 

Assessment of results heat production/enthalpy of decomposition... 

When a lateral analysis is required (see 5.2.4.1), the method and assessment of results shall be as specified in... 

If a lateral analysis is required (see 8.2.4.1), the method aid assessment of results shall be as specified in i.1.2 through 1.1.5. Table 1.1 illustrates the analysis process. The method and assessment specified are peculiar to liquid handling turbomachines. 

Gillings D and Koch G (1991) The application of the principle of intention-to-treat analysis of clinical trials Drug Information Journal, 25, 411-424 Greenwood M (1926) The errors of sampling of the survivorship tables Reports on Public Health and Statistical Subjects, No. 33, Appendix 1. London HMSO Grieve AP (2003) The number needed to treat a useful clinical measure or a case of the Emperor s new clothes Pharmaceutical Statistics, 2, 87-102 Haybittle JL (1971) Repeated assessment of results in clinical trials of cancer treatment British Journal of Radiology, 44, 793-797... 

Evaluation Methods. In testing paint materials, paints, and other coating materials, the properties or variations in properties often cannot be described quantitatively but must be assessed subjectively. A uniform system of evaluation has been established in the form of a numerical scale to facilitate the assessment of results and mutual understanding. This system should only be used if a result cannot be obtained as a directly measured value. For standards, see Table 1 ( Test evaluation ). 

Brathen, G. 1980. Lipolysis in milk. Automated determination of the acidity value with the autoanalyzer and assessment of results. Meierposten 69 (13), 345-352. (Norwegian). 

E. Helmers, Platinum emission rate of automobiles with catalytic converters D comparison and assessment of results from different approaches, Environ. Sci. Pollut. Res., 4 (1997), 100D103. 

The methods transfer protocol is the main driver that governs the conduct of the experiments and ensures that assessment of results generated is not unduly influenced by biases due to either (a) the analytical method or (b) inherent batch-to-batch variability of the active pharmaceutical ingredient or pharmaceutical dosage form. The methods transfer protocol establishes the predetermined acceptance criteria by which results will be judged to have either passed or failed the methods transfer. The criteria for assessment of success or failure contained in the methods transfer protocol is achieved through an iterative... 

It is necessary to study stability in solution in the solvent used to prepare sample solutions for injection in order to establish that the sample solution composition, especially the analyte concentration, does not change in the time elapsed between the preparation of the solution and its analysis by HPLC. This is a problem for only a few types of compound (e.g. penicillins in aqueous solution) when the sample solution is analysed immediately after the preparation of the sample solution to be injected. The determination of stability in solution is more of an issue when sample solutions are prepared and then analysed during the course of a long autosampler run. While the acceptance criteria for stabUity in solution may be expressed in rather bland terms by making a statement such as, e.g. the analyte was sufficiently stable in solution in the solvent used for preparing sample solutions for reliable analysis to be carried out , in practice it has to be shown that within the limits of experimental error, the result of the sample solution analysis by the HPLC method is the same for injections at the time for which stability is being validated as for injections immediately subsequent to the sample solution preparation. While this may be done by a subjective assessment of results with confidence limits, strictly speaking a statistical method known as the Student s t-test should be used. 

When the paired departments use fundamentally different methods of analysis, as is possible with serum enzyme determinations, for instance, the comparisons may be of only limited value. However, many laboratories now use AutoAnalyzer techniques for 60-80% of their total work, and a start on regular interlaboratory comparisons of these methods should be worthwhile and involve relatively little additional effort. Although the AutoAnalyzer methods used in the different laboratories might themselves show some differences in detail, the information provided by these comparisons should serve to detect in one laboratory the development of some systematic error in the routine performance of a method at an earlier stage than if the laboratory had itself been solely responsible for its assessment of results of quality control programs. 

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