Large component normalization factor

In this form the 2pi/2 does appear better behaved. The large component adds in another power of r in the lowest order, and yields the correct power dependence for a nonrela-tivistic 2p function. The problem of the singularity persists in the lowest order for the small component, but here the normalization factor Mq vanishes in the nonrelativistic limit, and so the small component also tends towards the correct behavior. As discussed in chapter 4, this is not true at r = 0, where the singularity persists. 

In a study in which individual urinary components were determined and repeated samples from the same individuals analyzed, Dobriner and co-workers23 found that the androsterone excretion in twenty normal males 21 to 76 years of age varied from 0.2 to 7.0 mg. per day, a 35-fold range. Age was a factor in contributing to the wideness of this range, since older individuals tended to excrete less, but each individual s androsterone excretion was distinctive, and large differences which were truly inter-individual were observed. One man of 72 excreted, for example, more than twice as much as one who was 21 years old. This study will be referred to further in a later discussion (p. 101). 

Detector sensitivity is one of the most important properties of the detector. The problem is to distinguish between the actual component and artifact caused by the pressure fluctuation, bubble, compositional fluctuation, etc. If the peaks are fairly large, one has no problem in distinguishing them however, the smaller the peaks, the more important that the baseline be smooth, free of noise and drift. Baseline noise is the short time variation of the baseline from a straight line. Noise is normally measured "peak-to-peak" i.e., the distance from the top of one such small peak to the bottom of the next. Noise is the factor which limits detector sensitivity. In trace analysis, the operator must be able to distinguish between noise spikes and component peaks. For qualitative purposes, signal/noise ratio is limited by 3. For quantitative purposes, signal/noise ratio should be at least 10. This ensures correct quantification of the trace amounts with less than 2% variance. The baseline should deviate as little as possible from a horizontal line. It is usually measured for a specified time, e.g., 1/2 hour or one hour and called drift. Drift usually associated to the detector heat-up in the first hour after power-on. 

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