Experimental design analytical range

The full-scale industrial experiment demonstrated the feasibility of a convenient, nonintrusive aconstic chemometric facility for reliable ammonia concentration prediction. The training experimental design spanned the industrial concentration range of interest (0-8%). Two-segment cross-validation (test set switch) showed good accnracy (slope 0.96) combined with a satisfactory RMSEP. It is fully possible to further develop this pilot study calibration basis nntil a fnll industrial model has been achieved. There wonld appear to be several types of analogous chemical analytes in other process technological contexts, which may be similarly approached by acoustic chemometrics. 

The first stage in deciding how to treat the results from a ruggedness test is to select a range of parameters to measure which will provide both qualitative and quantitative information on the method s performance. The second stage is to decide how best to evaluate the main effects, standard errors and interaction effects provided by the selected experimental design. For this discussion we will consider only the application of HPLC, normally one of the most complex analytical methods to evaluate. 

Cd2+ and the Pb2+ and all electrodes display the two peaks but to different extents. Despite the peak overlap, the electrode array can be calibrated for each metal ion using a three-way partial least squares regression (AT-PLS) [53]. The electrode array was employed to analyse three test samples of known concentration of Cu2+, Cd2+ and Pb2+ and the concentrations of each analyte predicted by the calibrated electrode array are shown in Table 10.1. As can be seen from Table 10.1 there is reasonable agreement between the actual and predicted values despite the fact that all electrodes respond to all analytes and that the electrochemical responses to lead and cadmium overlap. Further improvements would be expected if the calibrations were performed with a box experimental design, which encompassed the linear range of all the sensors. 

Otto s book on chemometrics [4] is a welcome recent text, that covers quite a range of topics but at a fairly introductory level. The book looks at computing in general in analytical chemistry including databases, and instrumental data acquisition. It does not deal with the multivariate or experimental design aspects in a great deal of detail but is a very clearly written introduction for the analytical chemist, by an outstanding educator. 

A decision about the validity/suitability of an analytical method for routine testing of study samples is taken, based on the estimated measurement error profile. Such a decision is possible only when no more than one section of the concentration range has its measurement error profile within the acceptance limits. For example, it is not reasonable to consider a method to be valid in a certain section of low concentrations and a different section of higher concentrations. In such cases, the measurement error profile is probably not precise enough to define a unique section of the range where the method is valid. In such cases, it is recommended to add a few more runs in the experimental design to obtain a more reliable estimate of the measurement error profile. 

A new experimental design for method evaluation was recently developed [18,24-27]. The method evaluation design recommends that at least 10 independent method runs should be performed on at least 10 different days. At each true concentration two method evaluation samples (ME samples) must be prepared, and the concentration of the analyte in the sample should be estimated on two different randomly selected days. For each run a new calibration graph should be prepared in the range of the method. The evaluation of the analytical method is obtained by a method evaluation plot (ME plot) showing the measured concentrations vs. the true concentrations (conventional true... 

Information on ship resistance has been determined from large numbers of tests on scale models of ships and from full-size ships, and compilations of these experimental results have been published. For a new and innovative hull form the usual procedure is to construct a scale model of the ship and then to conduct resistance tests m a special test facility (towing tank). Alternatively, analytical methods can provide estimates of ship resistance for a range of different hull shapes. Computer programs have been written based on these theoretical analyses and have been used with success for many ship designs, including racing sailboats. 

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