@rlopez thank you for your swift reply. But could you help me to solve the attached file element wise? The file with single input works fine but the one with multiple input does not.Single_Input.mw         Multiple_input.mw   Thank you in advance.

@dharr thank you for your input.

@mmcdara forgive me my ignorance but what is a terminal window? 

@mmcdara Could it be that the "sed" command does not exist in Windows but solely in LINUX?

@mmcdara and @tomleslie thank you both for your help. I will need some time to play with the solutions to fully understand your approach. @tomleslie I fully agree with your comments on the format but it is not me that created that format but the device we use for the measurements and unfortunately we cannot change the format. I also would like to express my gratitude for all the efforts both of you make on a daily basis to help people out! From my side this very much appreciated. Have a nice weekend

@Carl Love thank you for this additional clarification. I wish you a pleasant weekend.

@tomleslie thank you for your clear explanation. I wish you a pleasant weekend

@tomleslie thank you for your guidance. In general what would you use instead of vectors? In my former software this was the most convenient but probably not in Maple. I will take a closer look to your approach later on.

@Carl Love thank you for your solution! I will have a closer look later on.

@Carl Love thank you for your solution and the additional comment on return. All this information helps to get bit by bit better acquainted with Maple

@tomleslie Thank you for your help. The reason why they look the same is because the pH values in this example are very small which is not always the case in my data. Everything is now clear to me I was not aware that I had to add return.

@tomleslie Thank you for your help. I have been able to obtain the correct results now in the attached worksheet but I still have 2 issues:

1. How can I transform this to a procedure

2. How can I obtain the results for P50 and Pcor in a matrix?

Once again thank you for your time and help.Proc_example.mw

@tomleslie 

First thank you for your prompt answer. Second, my apologies but the procedure is only part of what I want to achieve and that is the reason why there are 3 parameters and the quantity S which are used in the full procedure. I am trying to get more experience with Maple by slowly transferring my Mathcad sheets to Maple. Maybe it will help you when I show the 'procedure' how it was in Mathcad: 

but as my in between result for P50 is wrong I removed part of it. As always you help, insight and "little tricks" are appreciated.

@Samir Khan Thank you for showing me this alternative method. I appreciate your commitment.

@mmcdara thank you for your workaround. I worked previously with mathcad where it was possible to fit with units. Your solution is a bit more cumbersome but at least it is a solution. Thanks again.