Under what circumstances would you use peak height for quantitation rather than peak area?
By deST on Monday, July 29, 2002 - 01:40 pm:
Hi Anon 0125
I use the peak height when my peaks are vey poor (with large tailing factor). Or when the SD of the peak heights are better than peak areas.
By B.Buglio on Monday, July 29, 2002 - 05:35 pm:
You could consider peak height quantitation when
the peaks are not completely resolved. In the case
of large tailing factors you should improve the
By vivek on Thursday, August 22, 2002 - 10:59 pm:
peak height method is mostly used in trace level analysis where peaks are small and the noise level is more. In that case measurement of area is difficult and peak height is the preferable choice
By ScottF on Tuesday, December 3, 2002 - 12:11 pm:
We do the type of work 'vivek' describes. We work with dirty biological extracts, and at levels approaching the limits of detection, there always seem to be small peaks or shoulders on one side or the other of the peak of interest that skew the area, or give the peak detection algorithm problems. At higher levels, they are too small to make a difference, be create problems at the low end of the standard curve. It seems to be impossible to pick integration parameters that work at all levels. By simply hand drawing in the theoretical peak shapes of the interfering peaks, we can usually demonstrate that the height isn't seriously affected.
On a perfect system, it shouldn't matter. But in trace level work, perfect systems seldom exist, and the time and effort to improve them aren't worth the small improvement in data quality. Peak height is quick, easy, and if it better fits the theoretical ideal, we use it. We don't usually abuse the practice by not correcting tailing peaks, or other fixable problems, but we can't make every sample a research project, either.
On the other hand, we seldom use it in our LC work, because we usually don't have the small peak problem. Also, retention times vary more in LC, and using height doesn't work quite as well. The areas are very similar over 0.1-0.2 minute retention time shifts during a 12-18 hour run, but the heights will change.
MS systems, because they can be very selective, help immensely with this issue. They are the closest approach to 'perfect' systems, and most of the time it makes very little difference, in our MS work, whether we use height or area.
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