Making the Final Choice

The best method is often dictated by the sample s properties. Analyzing a sample with a complex matrix may require a method with excellent selectivity to avoid 

The accuracy of a method depends on its selectivity for the analyte. Even the best methods, however, may not be free from interferents that contribute to the measured signal. Potential interferents may be present in the sample itself or the reagents used during the analysis. In this section we will briefly look at how to minimize these two sources of interference. 

In the absence of an interferent, the total signal measured during an analysis, Sjneas) is a sum of the signal due to the analyte, and the signal due to the reagents, Sn 

Compensating for an interference in the sample s matrix is more difficult. If the identity and concentration of the interferent are known, then it can be added to the reagent blank. In most analyses, however, the identity or concentration of matrix interferents is not known, and their contribution to S stead, the signal from the interferent is included as an additional term 

A sample that contains all components of the matrix except the analyte. 

---

The ASI algorithm is broken down into three steps. First the order of the drift (k) is estimated. Then all the possible polynomial GC models are estimated. Thus if k = 0, there are 3 models estimated k = 1, there are 7 models estimated and if k = 2, there are 15 models estimated. The inadmissible models (those models whose parameter estimates do not meet the constraints of the polynomial GC model) are discarded and the three best models are chosen. The third step compares the remaining models and makes the final choice. 

It may be argued that the twofold axis in the fiber direction of an oriented polysaccharide need not be an element of molecular symmetry, in which case the chemical evidence that the structure is based on a chain of cellobiose residues is the determining factor in making the final choice between the two chains shown in Fig. 8. However, this interpretation is not the usual one, and it is a line of thinking that has not proved useful to date. 

In addition to the cost of treatment other factors are of importance in making the final choice. They include ... 

There might exist several roots of the equation F(z, y,t) = 0 that satisfy condition 1°. To make the final choice of the root, consider the associated system (2.4) for the initial parameters y = y" and t = 0... 

Employers are primarily responsible for ensuring risk assessments are carried out and implementing controls to prevent tiie identified hazards from causing harm. Unions may disagree with the means by which the employer achieves this objective and may advocate alternative ways. However, the employer must make the final choice because it bears the ultimate legal accountability in tiie event of injury. It is no defence to say. .. that was what tiie union wanted . ... 

The design chain pull is 1.2 x 410 lb = 492 lb, and 492 lb/2 = 246 lb. Entering Table 10-7 with a chain pitch of 1.5 in. and a conveyor speed of 200 ft/min, we find that the capacity of C2062H chain is 775 lb. That is much more than the required capacity of 246 lb. The capacity of C2042 chain is 335 lb and that is adequate. However, the attachments on C2042 chain would have to be placed on every third pitch. Attachment plates on every third pitch must alternate between pin links and roller links. That is usually much more costly than putting every attachment plate on a pin link. The conveyor designer can make the final choice based on cost. 

---