Commit 41d1011e authored by Jan Zelenka's avatar Jan Zelenka
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Update water.md - added explanation

parent 4340a801
......@@ -9,9 +9,11 @@ Water is a bit problematic solvent for ISQ but measurements in it can be done! I
First and last line of the water template flushes the system to the water and then from the water to generally more accepted solvent - methanol.
### Why water is special?
### Why is water special?
Water mixes exothermically with other solvents like methanol or acetonitrile. To prove my point this is how it looks when you are going from methanol to water and back:
<img src="https://gitlab.science.ru.nl/jzelenka/isq/-/raw/master/waterpics/mixing_chart.png" width="700" >
Flow was set to **0.5 ml/min**, water was pumped from 5th minute. You see that the pressure raises sharply around 6th minute (0.5 ml dead volume) and then it slowly drops in course of approximately 5 minutes (2.5 ml volume before flushing MeOH). The same applies for the change back from water to methanol. The pressures are lower for the normal operating flow of 0.2 ml/min.
Whereas compounds soluble in methanol are also soluble in acetonitrile and vice-versa, analytes dissolved in water can precipitate when they are introduced to other solvent. From the abovementioned graph it is apparent that it takes approximately 2.5 ml of solvent to flush the system.
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