Peak-shape method

To sum up, in some instances the proposed tangent method and procedure of systematic error correction allows excluding the necessity of mathematical or chemical resolution of overlapped peak-shaped analytical signals. 

Using other methods for the calculation of plate count can result in different numbers, depending on peak shape. It should also be kept in mind that many other operational parameters, such as eluent viscosity, column temperature, flow rate, and injection volume, will influence the results of the plate count determination. 

Experience shows that such methods can result in significantly different dead volumes for the same GPC unit. There are at least two reasons for these observations (1) the peak shape is changed by the laminar flow with a parabolic... 

An interesting discussion about reliability of size/strain analysis methods can be found in Ref. [29] where the results on peak shape analysis of a round-robin sample are reported and commented. 

The use of high flow and fast gradient HPLC has gained a lot of popularity because of the ability to reduce LC/MS/MS cycle times during bioanalysis. In the case of fast gradient HPLC, peak shapes were improved and method development times were minimized, especially when multiple analytes with diverse functionalities had to be separated. Flows as high as 1.5 to 2 mL/min were achieved on a 2.1 x 30 mm Xterra C18 column.7 Details are discussed in a recent review.8... 

Note Mass accuracy is highly dependent on many parameters such as resolving power, scan rate, scanning method, signal-to-noise ratio of the peaks, peak shapes, overlap of isotopic peaks at same nominal mass, mass difference between adjacent reference peaks etc. An error of 5 mmu for routine applications is a conservative estimate and thus the experimental accurate mass should lie within this error range independent of the ionization method and the instrument used. [37] There is no reason that the correct (expected) composition has to be the composition with the smallest error. 

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