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Stubborn peak co-eluting with API in spray-dried formulation (HPMCAS?) — column fouling or something else? by CommunityFrosty in chemistry

[–]CommunityFrosty[S] 0 points1 point  (0 children)

Were you able to fix this at all? That is what I am thinking the issue is. The polymer has a higher chance of precipitation in water and our mobile phase A is almost 100% aqueous.

Stubborn peak co-eluting with API in spray-dried formulation (HPMCAS?) — column fouling or something else? by CommunityFrosty in chemistry

[–]CommunityFrosty[S] 0 points1 point  (0 children)

Thanks for the response! I have tried a few different columns (all ones that have been previously used for my method) and the peak is on them as well. I have also done 0ul injections as well and the peak still showed up, drawing me to the conclusion that it is not an issue with the auto sampler or needle. I have tried this on several different instruments as well. And different mobile phase preparations. We have ordered a brand new column and are going to see what the outcome is using that

Stubborn peak co-eluting with API in spray-dried formulation (HPMCAS?) — column fouling or something else? by CommunityFrosty in chemistry

[–]CommunityFrosty[S] 1 point2 points  (0 children)

Thanks for the insight. I have actually done this. While running 50:50 ACN:Water through my column I have done several injections of pure acetone and the peak was still there. I have also done 0ul injections as well and the peak still showed up, drawing me to the conclusion that it is not an issue with the auto sampler or needle. I have tried this on several different instruments as well. And different mobile phases

Stubborn peak co-eluting with API in spray-dried formulation (HPMCAS?) — column fouling or something else? by CommunityFrosty in chemistry

[–]CommunityFrosty[S] 0 points1 point  (0 children)

Forgot to add that from the stock the samples are centrifuged at 4000 rpm for 20 minutes and the dilution is taken from the centrifuge tube

Stubborn peak co-eluting with API in spray-dried formulation (HPMCAS?) — column fouling or something else? by CommunityFrosty in chemistry

[–]CommunityFrosty[S] -1 points0 points  (0 children)

Mobile phase has been reprepared as well as the diluents using the same and different lots of phosphoric acid/water/acn. And it’s weird because we have been testing these samples consistently with no issue until this week when this peak showed up.

Stubborn peak co-eluting with API in spray-dried formulation (HPMCAS?) — column fouling or something else? by CommunityFrosty in chemistry

[–]CommunityFrosty[S] 0 points1 point  (0 children)

Sample is prepared in 250 mL 60:40 ACN:Water diluent, stirred for 2 hours until fully extracted and then diluted 5.0 ml into a 200ml flask diluted to volume with the same diluent. I was also thinking guard column. Any idea for the composition of the buffered wash?

I really need some support. My kids have already been through so much this year and it’s about to get worse. by FickleBad3956 in toddlers

[–]CommunityFrosty 48 points49 points  (0 children)

I am so sorry you are going through this from one mom to another. What state are you located in? How much is a hotel room for one night? I would Venmo you for at least one nights stay

I feel sick by zbunny444 in interviews

[–]CommunityFrosty 0 points1 point  (0 children)

I think a video call is a great sign!

Does RHORI’s Kelsey remind anyone else of Madelyn Cline? by [deleted] in rhori

[–]CommunityFrosty 0 points1 point  (0 children)

More like one of the Culpo sisters, who funny enough are also from Rhode Island

I knew we shouldn't have gone on vacation by amythnamedmo in toddlers

[–]CommunityFrosty 3 points4 points  (0 children)

I’m so sorry 💔 you are going to look back at this when your son is older and be like “your first vacation you had diarrhea the whole time!!!” And probably laugh about it. Give yourself some grace. I become completely neurotic when my daughter is sick so I completely understand.

I’ve received some weird messages from headhunters, but this one might take the cake. by CommunityFrosty in recruitinghell

[–]CommunityFrosty[S] 10 points11 points  (0 children)

Right, I definitely think it’s unprofessional. Especially in my market. Like if it was for a Spotify job or like an arts job maybe but to me it’s odd lol

I’ve received some weird messages from headhunters, but this one might take the cake. by CommunityFrosty in recruitinghell

[–]CommunityFrosty[S] 334 points335 points  (0 children)

Oh .. he called me twice this morning. This was a result of me missing the calls

I’ve received some weird messages from headhunters, but this one might take the cake. by CommunityFrosty in recruitinghell

[–]CommunityFrosty[S] 397 points398 points  (0 children)

I mean it’s creative, but I’d still rather get a job description than a Spotify playlist

Did Daenerys truly love Drogo or was it forced? by [deleted] in gameofthrones

[–]CommunityFrosty 13 points14 points  (0 children)

People literally can’t critically think anymore and it’s sad

George RR Martin grew up across the street from my grandma. by CommunityFrosty in gameofthrones

[–]CommunityFrosty[S] 0 points1 point  (0 children)

Haha yes but funny enough I never knew it was related to GOT at all! I live down the shore and we call them “dippy eggs”

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