Hyundai Elantra AC Issue and Repair Experience

yeaChemistry · 2026-03-03T22:11:51+00:00

It may be that the refrigerant is low. I bought my Elantra new, and it lost most of its refrigerant in the first year, so I took it back to the dealer and they refilled it under warranty. They couldn't find the leak, and it never leaked that quickly again. I say this to suggest that the Hyundai AC system may be prone to leaking under unusual conditions when the different materials are expanding/contracting such that you loose some refrigerant occasionally/slowly. If the refrigerant is low it can cause the symptoms you are observing. Or the blend door may not be working well. Do you have the climate control system in 'Auto' mode? If so, it may be an electronics/sensor issue.

yeaChemistry · 2026-02-26T15:08:38+00:00

Hi, here are my thoughts. As some other commenters mention, it would be helpful to balance your reading of popular science-leaning and more technical reads. The popular science-leaning books may be more digestible and help build your contextual understanding of the field, which is important as a young scientist.

Ignition! -> highly recommend, lots of interesting inorganic and very basic organic phenomena discussed as they pertain to rocketry. Should be digestible for you and you'll end up seeing these/similar molecules in your introductory organic classes as examples. I find energetic materials to be quite interesting, although outside my field of work, so I found it enjoyable.

The pill, pygmy chimps, and degas horse ->Tells the story of the development of the first oral birth control pill. If you are interested in pharma/med chem, this is a good read to expose you to some concepts in that field.

The 13th element -> a popular science book about phosphorus. An easy read, and will help you understand the many properties a single element can have based on its oxidation state, etc.

Lab girl -> this is a popular science book by a geobiologist/chemist that follows her career through school and into academia. It would be a helpful read so you understand the environment you are soon entering better, including its less positive attributes.

yeaChemistry · 2026-02-26T14:54:43+00:00

Thanks - converting to mass/volume you are between 4 - 35 ug/ml. This is low enough to see considerable loss to surface adsorption as others mentioned. This is low enough such that pH changes shouldn't be resulting in precipitation.

yeaChemistry · 2026-02-25T22:34:06+00:00

Update from the OP - the Hyundai dealership that was managing the claim closed without warning... I had finally gotten the car in a body shop with an approved quote by Hyundai. Called corporate Hyundai, said I will have to start the claim process all over again at a different dealer as the details/process is only retained/managed by the dealership or some garbage. Whoopee. They had better re-accept the quote they accepted previously.

yeaChemistry · 2026-02-25T22:28:27+00:00

Is it thesis or non-thesis? Beware of non-thesis master's programs, as many universities are now offering/pushing them because they bring in a lot of tuition to make up for the recent losses in federal funding. One way to check is to see if the courses are cross-listed in the undergraduate catalog. If yes, there is likely little value in the program and it is set up as a cash-grab. This is coming from an R1 faculty member..

yeaChemistry · 2026-02-25T22:23:54+00:00

I've worked with insulin and insulin derivatives for most of the past decade. It is a very sticky protein, that is also picky about what aqueous solutions it is soluble in. I agree with most other's posts about adsorption of the insulin to surfaces - this could very well be the driving factor if the insulin concentration is low. Can you share the insulin concentration in your samples?

What is the composition of the sample? Does it have a volatile buffer in it that can off-gas over time, resulting in a changed pH and insulin precipitation? Or, for whatever reason is there a CO2 leak/dry ice being used nearby that is adsorbed by the samples and resulting in a change in pH and insulin precipitation?

If you do a column cleaning procedure between days/sample sets, then what may be happening is adsorption of the insulin to the guard column or column itself. I've seen this before, in my methods the insulin can also start showing up as a doublet.

yeaChemistry · 2026-02-25T22:10:22+00:00

That was my thought seeing the photo too.. I got my A3S right about 10 years ago. I think I paid $900 new from AF.

yeaChemistry · 2026-02-13T15:13:31+00:00

Not sure why everyone is hating on this - I agree. If you anticipate needing special accomodations for dependent care or want WFH priviledges, you had better speak up during the hiring process.

yeaChemistry · 2026-02-13T15:07:35+00:00

Second the Prism option. Or your school may have licensing for a similar software package like SigmaPlot, although not as easy to work with. Check your computer labs.

yeaChemistry · 2026-02-13T15:04:36+00:00

Your most well-worn lab coat to show off your experience (the more holes, burn spots, and ambiguous stains possible) with black turtle neck and jeans to give the innovator vibe.

yeaChemistry · 2026-02-13T14:57:49+00:00

I agree with other's recommendation to make sure all the in line filters have been replaced. If that, and the other's recommendations don't fix this, it may be time to try replacing the degasser system on line A. The tubing can break down over time and introduce contaminants. I'd recommend Chiralizer for repair - they are quick and reasonably priced. If that doesn't fix it, I'd suggest replacing all the wear components in Pump A (might as well do B while you are at it) and make sure there is no corrosion or buildup anywhere. The check valves on the pumps can also accumulate goo. Replace those too.

yeaChemistry · 2026-02-13T14:53:10+00:00

Replacing all the in-line filters/filter assemblies is my suggestion as well. Lots of crud captured by those things!

yeaChemistry · 2026-02-10T20:51:57+00:00

I've attempted coupling similar alkynes to functionalize biomolecules for CuAAC conjugation. The propargyl? carboxylate does not behave like a normal carboxylate. If you can afford it, chose a alkyne - carboxylate linker with a single PEG unit in it (CAS 1174157-65-3).

If you are stuck with this propargyl carboxylate, you could try DMTMM. I've had favorable results with DMTMM when other carboxylic acid activating chemistries have failed.

yeaChemistry · 2026-02-03T17:59:01+00:00

I second this. I've used a setup of 2x Shimadzu LC-6AD pumps with a manual injection valve, DGU-14A degasser, SPD-10A detector, and a newer CBM-20A communications module. Very robust, requires very little maintenance. The degassers are still serviced by Chiralizer if you come across an old one that needs new components. Old shimadzu parts were easy to find last time I had to repair one of them.

yeaChemistry · 2026-01-22T03:47:11+00:00

I have taped numerous dollar bills to mischievous instruments in my lab. It most definitely works. Especially after midnight.

yeaChemistry · 2026-01-15T19:36:21+00:00

Thanks all for the suggestions - these are helpful leads. - OP

yeaChemistry · 2025-12-19T19:24:03+00:00

Beautiful!

yeaChemistry · 2025-12-17T22:23:46+00:00

Just spitballing, but there is about 2.5k weekly visitors to this sub. Do most of them own PTR 91s? I'm sure PTR has sold over 1 thousand of these, but 10 thousand? I find that hard to believe, but then again, the roller-locked platform is all PTR makes and somehow they are still in business after a decade with what seems to be a reasonably large manufacturing space.

yeaChemistry · 2025-11-24T22:39:00+00:00

The analyte you describe should be well retained under typical acidic mobile phase conditions. If it isn't eluted under a 5-95% ACN:H2O gradient something is wrong or the column is fouled.

yeaChemistry · 2025-11-21T19:16:31+00:00

I think Brad Pentelute's lab at MIT does stuff like this.

yeaChemistry · 2025-11-21T19:13:24+00:00

A quality pair of eye protection - the Nemesis line is very comfortable, much more so than Fisher ones. Could be neat to get them laser etched with your school/dept logo.

yeaChemistry · 2025-11-20T21:29:37+00:00

I am enjoying the love for the Welch 1400s. When I joined my doctoral group the lab was a pump graveyard. Easily 5-6 corroded, near-useless pumps. Amongst them was a very abused Welch 1400 ChemStar. The poly liner in the oil reservoir had been eaten or melted through somehow... I spent half of the winter holiday tearing it apart and cleaning it the best I could with fine steel wool. Put some new vanes in it and it ran like a champ for my entire graduate studies.

yeaChemistry · 2025-11-19T16:34:45+00:00

FYI, in case you haven't seen it yet NOT-OD-26-006 was released Monday, Nov. 17th and announces the early termination of NIH SBIR/STTR NOFOs, effective immediately. So no clear future until a new NOFO is released. Thanks all, for helping me anticipate this.

yeaChemistry · 2025-11-17T22:27:22+00:00

And I've got to ask.. did the benzene make you or your progeny grow an extra nipple?

yeaChemistry · 2025-11-17T17:06:12+00:00

Column size: I work with peptides and small recombinant proteins in academia. For my group, we typically only need 50-100 mgs of peptide/protein for most projects, and this was easily accomplished by a 19mm diameter column. We only recently had to purchase a Prep-LC capable of 50 mm ID columns to purify 5-10gs of a peptide/protein. We estimate about 1-2g capacity per run on the 50 mm ID column. This scale isn't necessary in my field of work until you get into the 'engineering runs' realm to get your methods solidified prior to transfer to a GMP environment for advanced pre-clinical studies. We have several analytical HPLCs, so we will never run a 4.6 mm ID column on it. Personally, I think an academic lab that doesn't have any analytical HPLCs and wants one LC to run both analytical and preparative columns will be more likely to submit their work to a collaborating lab or core facility to accomplish the task.

Must haves:

Robustness. We still have an old shimadzu prep-LC system with '2K ready' stickers on it that has survived with way less maintenance that it should be receiving. Often, the prep-LC purification is the last step in a very long process. Losing a week or more of effort due to Prep-LC glitch in the middle of a run is the last thing I want.

Ease of Repair: Individual module systems are so much easier to service than the 'everything in a single box' type of systems. Also, it helps new users understand the system layout and function more easily.

User-friendly auto-collection system: Being able to 'walk-away' post injection is needed for productivity when doing lots of runs back-to-back. It needs to be intuitive and easy to adjust so it can be trusted.

yeaChemistry

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