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Is there a particular benefit to start any kind of measurement with the least concentrated solution and then work my way up to the more concentrated solution?

In one of my experiment, we measure the UV absorbance value of a solution beginning with lowest concentration. Weirdly, the demonstrator did not clean the apparatus and simply rinse it with higher concentrated solution that is to be measured.

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  • $\begingroup$ Can you be more specific with your question? For example, what type of experiment are you running? If this is an experiment using the same measurer, you might think that less concentrated solutions might become more concentrated if more concentrated solutions are measured first. However, it is always good practice to clean measurers after a measurement. Also, the effect of the bad practice depends on the volume of solution. $\endgroup$ – Ethiopius Mar 26 '19 at 17:39
  • $\begingroup$ In one of my experiment, we measure the UV absorbance value of a solution beginning with lowest concentration. Weirdly, the demonstrator did not clean the apparatus and simply rinse it with higher concentrated solution that is to be measured. $\endgroup$ – Dennis lul Mar 26 '19 at 17:44
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    $\begingroup$ That is a valid experimental procedure as well. I believe your instructor measured absorbance starting with the lowest concentration solution is because of the technique used (rinsing apparatus with next solution) as it would be highly problematic to follow this procedure if we measure starting from the highest concentration solution. This procedure should work just as well as cleaning the apparatus if the solutions do not vary in chemical composition. Thus, choosing which procedure to follow often comes down to personal preference. $\endgroup$ – Ethiopius Mar 26 '19 at 17:49

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