Post in Bubble forming at the tip of SS emitter for nano ESI: ABRF Discussion Forum: ABRF Discussion Forums

Hi Emanuele, As other ABRF members suggested and I forgot to mention we also sonicate our Buffers every time we refill the mobile phases. We do flush air in between each sample sets/projects, purge+ flush air, every time system is on idle isocratic flow for longer than overnight we never let the system idle, we always run it on isocratic when not running samples but we found out we will need to to purge and flush air each time system is left on isocratic overnight, we also clean the ion transfer tube every 2 weeks by sonication in 100% isopropanol. Regarding sonicating emitter/ nano column glass tip, since we only sonicate 4 second for each 3 step, You can hold it as only the tip touches the methanol, isopropanol and H20 in the beaker which you put in water bath sonicator or you can use thermos too which hold the tip inside the solution in beaker, we did not have good luck with squirting buffer and blowing air on the tip and 40 sec sonication in this 3 solution works so far, we can column/tips that have lasted 4 months using this cleaning process if we load 500 ng /injection and we run samples 24/7,we have noticed running 1 ug/injection although it's ok on our columns but we get up to 2 months of column life time, where our traps usually last 1-2 month maximum, we use Thermo EZ columns here but in past used to pack our own nano columns here. Hope this helps and thanks ABRF members for other tips regarding this issue. Regards, Khatereh Motamedchaboki, PhD. Director, Proteomics Facility Sanford Burnham Prebys Medical Discovery Institute 10901 North Torrey Pines Road La Jolla, CA 92037 Tel: (858) 646 3100 Ext: 3710 Fax: (858) 795 5221 http://www.sbpdiscovery.org/technology/sr/Pages/LaJolla_Proteomics.aspx

-----Original Message----- From: ABRF Discussion Forum <email obscured>] On Behalf Of Emanuele Scollo Sent: Wednesday, February 10, 2016 1:39 PM To: <email obscured> Subject: Re: [ABRF Discussion Forum] Bubble forming at the tip of SS emitter for nano ESI Hi Kathereh I purge the mobile phases and flowmeter and mobile phase is constantly running through the column, but maybe I should try conditioning the column as you suggested prior to starting a run. As for the sonication of the emitter should I submerged it all in the solvent? If this is the case how do I make sure that the emitter does not float in solution? Thanks Emanuele -----Original Message----- From: ABRF Discussion Forum <email obscured>] On Behalf Of Khatereh Motamedchaboki Sent: 09 February 2016 21:23 To: <email obscured> Cc: e.scollo <email obscured>> Subject: Re: [ABRF Discussion Forum] Bubble forming at the tip of SS emitter for nano ESI Hi Emanuele, Our column and pre-column(trap) equilibration goes up to 500 nl/min with 800 ba max pressure cap, and we run this for 5-10 min, we also do purge solvents and flush air to start with, while you are running it at 500 nl/min, isocratic at 50:50 A:B, disconnect the column out to union wait for flow for half min, connect it again, then disconnect the trap from the union and wait for flow to flush the union and then connect again, then connect the trap to T connection, disconnect waste line and column from T, let the let it flow for half min-min, then connect the column or emitter and let it flow for half min then connect the waste line, you can sonicate the T union in methanol or isopropanol for 5 min too, rinse it with HPLC grade water then and connect again, make sure there is no air before connecting the column or emitter, our droplet issue usually resolves by disconnecting waste line to T while on isocratic flow and then connect it again, make sure you are tightening it well but not too much. If this does not resolve the issue ,sonicate the tip, if you are running ug amount of samples on nano columns you will need to sonicate the tip every 10 days to avoid blocking it fast, we have a thermo tool which we use to hold the emitter/column tip on top of the beaker to sonicate the tip as I recommended in my 1st email, The next step would be adjusting the voltage and distance, if all of this does not help, check your source, it might be the spray source resistor has gone bad and need to be replaced and it's not applying right voltage in the tune setting to your column/source. That has happened to us one, and your service engineer should be able to fix the source, if the resistor is ok, check it on a new column /emitter then maybe your column tip or voltage connection is gone bad and you need to replace the column/emitter, all of this can be done in less than hour procedure. Please feel free to call me if you have any other questions, Good Luck, Khatereh Motamedchaboki, PhD. Director, Proteomics Facility Sanford Burnham Prebys Medical Discovery Institute 10901 North Torrey Pines Road La Jolla, CA 92037 Tel: (858) 646 3100 Ext: 3710 Fax: (858) 795 5221 http://www.sbpdiscovery.org/technology/sr/Pages/LaJolla_Proteomics.aspx -----Original Message----- From: ABRF Discussion Forum <email obscured>] On Behalf Of e.scollo Sent: Tuesday, February 09, 2016 11:39 AM To: <email obscured> Subject: Re: [ABRF Discussion Forum] Bubble forming at the tip of SS emitter for nano ESI Hi Kathered Thanks for your reply. I noticed that when I get the emitter very close to the source then the droplet disappear but then it forms again. Obviously I cannot have the emitter too close to the source otherwise the spray is not going to be stable, however I am not sure I understood well how you use the pump script to get rid of air. The flow on the nano pump is 300 nl/min so do you mean increasing the flow to remove air? Also how do I understand whether the issue is the emitter or not? Thanks Emanuele ―― View topic http://list.abrf.org/r/topic/3XBCw8m8h6lU3hWtMdQ5SU Leave group <email obscured>?Subject=Unsubscribe ―― View topic http://list.abrf.org/r/topic/2IOc0NyIYIjszjHDJGOR30 Leave group <email obscured>?Subject=Unsubscribe ―― View topic http://list.abrf.org/r/topic/3G9eKyNr8e01xsgRqaWzpC Leave group <email obscured>?Subject=Unsubscribe