tag:blogger.com,1999:blog-9209375845415652006.post1612319465539664743..comments2024-01-24T09:56:18.495-05:00Comments on HPLC CHROMATOGRAPHY HINTS and TIPS FOR CHROMATOGRAPHERS [HPLC TRAINING ARTICLES] : HPLC PUMP SEAL WASH & FLUSHING THE HPLCHPLC EXPERThttp://www.blogger.com/profile/04810178046245936465noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-9209375845415652006.post-55853780993270003912019-02-07T16:03:31.480-05:002019-02-07T16:03:31.480-05:00Thank you for this helpful information!Thank you for this helpful information!Anonymoushttps://www.blogger.com/profile/04742775408413604558noreply@blogger.comtag:blogger.com,1999:blog-9209375845415652006.post-20418596728359404282019-01-11T04:24:12.902-05:002019-01-11T04:24:12.902-05:00Thank you for the post! I started to use HPLC so t...Thank you for the post! I started to use HPLC so too many questions come up. <br />So thankful to find your blog!<br />Anonymoushttps://www.blogger.com/profile/06077205325949395565noreply@blogger.comtag:blogger.com,1999:blog-9209375845415652006.post-14787530020440437882018-08-17T08:10:54.098-04:002018-08-17T08:10:54.098-04:00This was a very helpful post. Thank you! I always ...This was a very helpful post. Thank you! I always thought twice about canceling the Seal Wash Kit line item from my orders, but now I know for sure that I don't need it for my applications!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9209375845415652006.post-25681952346844033412017-04-18T13:50:33.921-04:002017-04-18T13:50:33.921-04:00"The purpose of the Seal Wash solution is to ..."The purpose of the Seal Wash solution is to remove buffer crystals". Your NP solvents do not contain buffers so no seal wash system is needed (a pump w/o the seal wash option would be used). Many manufacturers sell special NP only piston seals for use with their pumps. However, if your pump has a seal wash system installed, then you need to use it. For your specific example we would choose a Seal Wash solution which would keep the seals "wet" (to seal) and not dry out (which may result in leaks and/or produce a very annoying high pitched sound!). You mobile phase is essentially Heptane/IPA. IPA can mix with both water and Heptane so would be the best choice. If used, run it using a very slow flow rate.<br /><br />Needle wash solution is chosen based on sample solubility. Both your mobile phase and Needle wash solution are usually the same liquid because you want to rinse off any residue. If you have a very sticky sample OR if you have not selected a very good mobile phase which FULLY dissolves your samples (go back and develop a better method), then the needle wash solution should incorporate stronger solutions which DO dissolve ALL of the sample material off (Note, these stronger solution rinses can often be followed with mobile phase rinses to reduce contamination when you put the needle and loop back in the flow path). A well developed HPLC method where the sample dissolves into the mobile phase and the instrument is well maintained would rarely need a "needle wash" step(s) as part of the method. BTW: When used with proper HPLC methods, some brands and models of HPLC autoinjectors do not need needle washes at all because their design provides for complete and continuous flushing of the injectors flow path during the method. This means the needle and loop are always full of fresh, clean mobile phase and the only kind of needle washing that might be needed would be a needle "dip" to rinse off the outside surface of the needle (or use one of the latest "needle washing stations").<br /><br />HPLC EXPERThttps://www.blogger.com/profile/04810178046245936465noreply@blogger.comtag:blogger.com,1999:blog-9209375845415652006.post-23929371094002613862017-04-18T13:27:06.807-04:002017-04-18T13:27:06.807-04:00Which seal wash solvent should I use if I am runni...Which seal wash solvent should I use if I am running normal phase aplication. My mobile phase is 3:900:100 = Water:heptane:IPA. And which solvent should i use for needle wash? Thank you for your help! Lejlahttps://www.blogger.com/profile/15458189889948332617noreply@blogger.comtag:blogger.com,1999:blog-9209375845415652006.post-40765475682568488382016-07-17T08:35:12.831-04:002016-07-17T08:35:12.831-04:00The best seal wash rinsing solution would depend o...The best seal wash rinsing solution would depend on the mobile phase composition used. The purpose of the seal wash solution is to remove buffer crystals so a pure organic solution of acetonitrile (ACN) should not be used alone. To dissolve the buffers, a suitable aqueous phase solution should be used (e.g. mixture with some organic such as 20% MeOH or ACN. *IPA has poorer solubility so is not a top choice for RP methods). <br /><br />Since the RP piston seals are designed for use with 100% organics such as ACN, no accelerated wear would be expected if you used pure ACN as the seal wash solution. However, you would not be using the seal wash system for what it was designed for, to dissolve and rinse buffer salts away from the seals. HPLC EXPERThttps://www.blogger.com/profile/04810178046245936465noreply@blogger.comtag:blogger.com,1999:blog-9209375845415652006.post-80900280964310953722016-07-16T23:14:32.443-04:002016-07-16T23:14:32.443-04:00Isnt the use of acetonitrile not the best idea for...Isnt the use of acetonitrile not the best idea for a seal wash solution since it can degrade the seals over time, making them brittle and more likely to fail? That's why I always use water and IPA. Thoughts?Brockboyhttps://www.blogger.com/profile/00666731966646475725noreply@blogger.comtag:blogger.com,1999:blog-9209375845415652006.post-30510260849996616312014-05-29T02:14:32.868-04:002014-05-29T02:14:32.868-04:00Very useful for analysisVery useful for analysisAnonymousnoreply@blogger.com