Actually, more isn’t necessarily better but none is not an option either.
Calibration curves are used to actually determine concentrations of compounds of interest in your samples.This idea being that the lowest and highest unknown concentrations are bracketed by at least 2 standard concentrations from your standard curve. https://terpconnect.umd.edu/~toh/models/CalibrationCurve.html If a unknown is outside you calibration range, then you need to redo, to bracket that concentration in your curve, as long as the curve is still linear. If the curve cannot be increased, then dilutions are needed to bring the unknown concentration in the calibration range.
One can talk about the time interval between calibrations (weekly, monthly, etc.). This interval depends on how complex or dirty the samples are. If degradation of the separation is occurring, then a calibration is warranted. EPA test methods, in particular, say what the recommended calibration interval is. Also, if the column is removed for any reason, then a calibration is warranted.
Also, there is the use of duplicate samples, calibration check samples, and spiked samples that can be used during a run. These samples are to access the viability of the calibration curve. All of these should be used to some extent.
There is quite a bit of information in this post. The point is, one should not ignore these points because they are hard or make analysis more complicated. These should be used to better the analysis.
David Slomczynski, Ph.D; GeoMetrick Enterprises
This topic really is tough for people to understand. It is so easy just to go into various search engines and type in a topic and get out information but, that is only PART of the information out there. So much information is located in physical media (books, journals, etc) that people have ignored by it not being ‘convenient’. In the science fields, many researchers do not go back far enough in the literature and this is to their detriment. There have been some amazing science problems worked out and discussed in older papers. Just using only the last 20 years of research or so, means people are using an arbitrary point of reference. Yes, older literature means you have to look through actual physical media and not on a computer screen. I think researchers should not be intimidated by it, after all, the earlier researchers had to do it that way also.
I will give an example. In my MS and PhD theses, I referenced a paper from 1883. This was the first scientific paper describing the actual enzyme I was working on. Why was that important? The researcher, Yoshida, described the enzymatic reaction in a very succinct and beautiful way. Remember, this paper was published before the term ‘Enzyme’ was coined, so Yoshida used the term ‘diastase’. Beyond being historical, using this reference also showed how much interest there was in this research topic.
In another example, I found work that was done in the 1940’s by the USDA that superseded some of the research I was involved with which proved it was not unique or novel. Going back to the original literature, showed how people have misinterpreted the original work and did not read the original close enough to actually understand the research.
Literature research is important for both research and for patent purposes. This has to be one of the most important of all the work the researcher has to do. “Due Diligence” in literature search can save researchers time from re-inventing the wheel. This is why it is important for researchers to do as much literature research as possible.
David Slomczynski, Ph.D; Geometrick Enterprises