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- Posts: 525
- Joined: Tue Sep 15, 2015 2:07 pm
"The Agilent tech that examined your HPLC system has no formal training or ability to troubleshoot the degasser in your HPLC pump." <- How do you know? Do you personally know the tech that serviced my HPLC? How do you know that he did not have other training before joining Agilent? You assume that Agilent was his first and current job and does not have any other experience."
- I did not assume anything as I already know. No need to know who the tech is. Not relevant. As stated before, Agilent does not provide training in servicing the degasser. They do not "service" the degasser. Techs replace them. This is official policy and what they are trained to do (we know this because we have provided professional service training to Agilent and other instrument companies in the past). They would not have the equipment or time to do so on-site (not possible). Techs do what they are told.
"Note: I do not believe any of my comments suggested that your main problem was caused by using a broken degasser (which you had)." <- Again, you are making the assumption without 100% knowing that the degasser was broken. As I stated, I saw no differences in my baseline, quality of chromatogram or overall performance between the old/replaced degasser and the new/replacement. But if you think the old one was broken, based on the fact that nothing changed in the quality of the chromatogram or baseline or overall system performance, then the new degasser is broken as well.
-You did not read my response. The degasser is broken, but as noted before, is not related to the issue you think you are having. I would not speculate on what changes would be seen before or after changing the degasser out. It is overdue for service/replacement, which was my point, again and again. Even you said the tech replaced it. They probably did so because if they have serviced these modules before, then they know that they fail on or before 3-years so it was due for replacement no matter what and could only help improve the condition of the HPLC system.
"Fact of the matter is that I still have a negative dip that has not changed in intensity with all of this work so far."
-You do not know, what you do not know. At this point you do not have the needed training to operate the system. Ask your school or business to hire someone to help and train you. Many years of professional practical experience are required just to learn the basics. You do not have the needed basic knowledge or experience to know this yet. This makes it impossible to provide advice or support to you. You really need to have someone come in and repair the HPLC first. Next, have each module checked to insure it meets factory spec (OQ or PV would be fine). After demonstrating that you have a clean and functional instrument, then have someone come in to review your proposed "ethanol" method by HPLC. They should be able to show you how to develop and run a valid method to do so, but you may need some additional items to do so as your method is still invalid.
"How often does the Stator, Rotor Seal or metering valve cause issues?":
-Again, if you are using the instrument, then you should have a basic understanding of the flow path and how these critical parts relate to the operation of the injector. AND how as they wear and/or are damaged, carryover contamination (and other problems) may occur. Understanding these basic things is critical to your training. [More info at this link: https://hplctips.blogspot.com/2015/02/c ... on-in.html ]
"A complete system pressure test was performed today and in all cases it passed. No leaks present. The dip most likely is caused by air being introduced - but not from a leak."
-Great news no leak, but again, your conclusions are not based on knowledge of how the system works. Air is not the issue. Your method is, (this has been noted many times), but you do not yet have the needed knowledge to understand this (and this is not meant to be critical of you, it is a fact. No one with your level of HPLC training would be expected to know any of these things yet).
As you do not have the experience needed to act on advice given, I will wish you good luck and hope that your school or employer brings in assistance for you. This forum is not meant to provide five years worth of free training to people.
- I did not assume anything as I already know. No need to know who the tech is. Not relevant. As stated before, Agilent does not provide training in servicing the degasser. They do not "service" the degasser. Techs replace them. This is official policy and what they are trained to do (we know this because we have provided professional service training to Agilent and other instrument companies in the past). They would not have the equipment or time to do so on-site (not possible). Techs do what they are told.
"Note: I do not believe any of my comments suggested that your main problem was caused by using a broken degasser (which you had)." <- Again, you are making the assumption without 100% knowing that the degasser was broken. As I stated, I saw no differences in my baseline, quality of chromatogram or overall performance between the old/replaced degasser and the new/replacement. But if you think the old one was broken, based on the fact that nothing changed in the quality of the chromatogram or baseline or overall system performance, then the new degasser is broken as well.
-You did not read my response. The degasser is broken, but as noted before, is not related to the issue you think you are having. I would not speculate on what changes would be seen before or after changing the degasser out. It is overdue for service/replacement, which was my point, again and again. Even you said the tech replaced it. They probably did so because if they have serviced these modules before, then they know that they fail on or before 3-years so it was due for replacement no matter what and could only help improve the condition of the HPLC system.
"Fact of the matter is that I still have a negative dip that has not changed in intensity with all of this work so far."
-You do not know, what you do not know. At this point you do not have the needed training to operate the system. Ask your school or business to hire someone to help and train you. Many years of professional practical experience are required just to learn the basics. You do not have the needed basic knowledge or experience to know this yet. This makes it impossible to provide advice or support to you. You really need to have someone come in and repair the HPLC first. Next, have each module checked to insure it meets factory spec (OQ or PV would be fine). After demonstrating that you have a clean and functional instrument, then have someone come in to review your proposed "ethanol" method by HPLC. They should be able to show you how to develop and run a valid method to do so, but you may need some additional items to do so as your method is still invalid.
"How often does the Stator, Rotor Seal or metering valve cause issues?":
-Again, if you are using the instrument, then you should have a basic understanding of the flow path and how these critical parts relate to the operation of the injector. AND how as they wear and/or are damaged, carryover contamination (and other problems) may occur. Understanding these basic things is critical to your training. [More info at this link: https://hplctips.blogspot.com/2015/02/c ... on-in.html ]
"A complete system pressure test was performed today and in all cases it passed. No leaks present. The dip most likely is caused by air being introduced - but not from a leak."
-Great news no leak, but again, your conclusions are not based on knowledge of how the system works. Air is not the issue. Your method is, (this has been noted many times), but you do not yet have the needed knowledge to understand this (and this is not meant to be critical of you, it is a fact. No one with your level of HPLC training would be expected to know any of these things yet).
As you do not have the experience needed to act on advice given, I will wish you good luck and hope that your school or employer brings in assistance for you. This forum is not meant to provide five years worth of free training to people.
