Analytical limits thereof

We have described elsewhere the nature of the MI FTIR spectra of PAHs and their derivatives (1, 12, 13, 1J>, 18, 21-24) the following points are especially significant. First, FTIR spectra devoid of rotational structure and having individual bandwidths on the order of 2-7 cm are obtained both for PAHs and for polar derivatives thereof (such as nitrogen heterocycles) These spectra are sufficiently characteristic to enable identification of individual isomers to be made in mixtures [e.g., the six methylchrysenes (12) and the various mono- and dimethyl naphthalenes and biphenyls (24)]. Second, detection limits for individual PAHs can be as low as 50 ng, if special "micro samp ling 1 deposition apparatus is used (23) Third, Beer s law plots typically are linear over 1.5-2 decades in PAH concentration by the complementary use of two different deposition cells, linearity over 3 decades in PAH concentration for Beer s law plots can be approached (23). Finally, for both MI FTIR and MI fluorescence spectrometry, analytical precision of ca. 3-7 % relative standard deviation can be achieved. 

Fresh stock solutions should be used immediately after preparation if possible and certainly within 24 hours (one day) of preparation when used for comparison to stored stock solutions that are kept at the anticipated storage conditions. The number of rephcate injections of the freshly prepared and stored stock solutions (or dilutions thereof) should he sufficient to achieve the precision required to make such comparisons statistically meaningful (see Section 8.2). The solutions should be analyzed at relevant intervals spanning the maximum anticipated storage duration in order to expose any trends in the stabihty with time. The storage stahUity of an analyte stock solution is defined hy the period over which the mean peak area or peak area ratio of the stored solution deviates from the mean peak area or peak area ratio of the fresh solution by no more than the acceptable limit established in advance (10 % is a value that is often chosen). If a stock solution falls outside of acceptance criteria, an additional comparison can be made to verify instabihty. If the verification indicates that the analyte in solution was in fact stable (e.g. indicating a prior preparation error rather than instability), then at... 

In this review we first present and elucidate fundamentals of the FP formalism within a unified conceptual framework, which naturally integrates the existing techniques. We then discuss applications thereof, with emphasis on the practical use of FP techniques in biophysical systems. Our focus here is on covering a diverse set of analytical techniques the number of reviewed biological applications is thus limited, out of necessity. We focus on three specific areas channel transport, receptor binding and adhesion, and single-cell growth and division. 

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