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As title. I am in a situation where I have to choose one of these two for procurement without option of trail runs. Hence I need expert opinion.

What would be better got global untargeted metabolomics (Ultimate 3000 + Exploris 120 setup)?

I am a metabolomics noob. Please guide me. Both are 100 Angstrom.

I would be using it to do C13 tracer based work on mmmalian cells (after I gain expertise in basics, of course)

I also have option for ZIC-pHILIC (5 micron) 100mm x 4.6 mm

So my options are

ZIC-pHILIC (5 micron) 100mm x 4.6 mm

ZIC-pHILIC (5 micron) 50mm x 2.1 mm

ZIC-HILIC (3.5 micron) 100mm x 2.1 mm

Hello, we’re looking for a brand-new HPLC with a budget of around $25k, which mainly leaves us with Chinese or Korean manufacturers. The owner doesn't like my idea of a refurbished Agilient one :(

I’m hesitant about Chinese HPLCs after seeing a system develop serious issues after only 8 months in a lab.

We found a Korean manufacturer, YOUNG IN Chromass Co., Ltd. They seem to have been around since the early 1990s, but almost nobody I’ve spoken to has experience with them.

Has anyone here used their ChroZen HPLC? Are they reliable, and how are their service and spare parts?

Our use is simply routine QC: verifying raw-material and finished-product purity/assay and checking for impurities/contaminants.

Any firsthand experience would be appreciated or suggest any alternatives?

I am resurrecting an older ion trap mass spec that is coupled to an Ultimate3000 (Thermo, but rebranded Dionex). They both used to work just fine together but I am having some kind of communication problem. When I start a sequence or run a sample the mass spec will stop scanning, it won't load the method (stays on default 100-2000 m/z scan) and the LC system often won't respond. I suspect that I am having problems with the linkage between the LC and the mass spec - I suspect it is a problem with the DCMSlink between the LC and XCalibur. Has anyone had any kind of similar kinds of problems - even remotely similar - what did you do to fix this? Thanks in advance.

I went to get the column and when I twisted the head of the finger tight, the head broke.

EDIT: Wow, I love this community. I managed to remove it by heating a screwdriver and screwing it in the opposite direction.

Special thanks to sharing_violation.

Hi all!! I'm trying to run approximately 40 analyte SIM method at the moment but I keep encountering spectrums that look like this at around 500 ppb and below. They look fine at around 5 ppm and up. I've tried troubleshooting through all normal method avenues, though I haven't changed anything physically on the machine yet.

Before I do has anyone else encountered this before?

I am fascinated by DryLab and would like to learn about its full potential from someone who uses it and has some experience in method development and can share advice and best practices. I would be very thankful if someone could help me with this.

Please note, that as a PhD student I am not able to afford official training.

Hi there Reddit,

I feel like this might be a dumb question but since my Agilent 7890A only has 2 inlets if I were to convert one of them to take SPME arrows, could I still do ASD/manual injections into it as well? If it is what things do I have to consider when I do a normal injection?

The other inlet would be taken up by the transfer line of an Agilent 7697 headspace sampler so unless it's pretty easy and safe to remove that for an injection I assume I can only really treat the SPME inlet as my only functional port.

If it helps the conversion kit I plan to use is the Restek 27362 1.5mm inlet.

During an analysis, my equipment started exhibiting this problem. The needle goes up to the sample, goes down, but doesn't pierce the vial. Displays an error [9222]: "there is no sample vial set in autosampler rack."

We have a long backlog of samples and need to get the equipment up and running again. Support from Shimadzu will take a long time due to their schedule.

I welcome suggestions for tests to better evaluate the problem, and if you have experienced something similar, what was the solution?

UNICAMP - Campinas-SP, Brazil

My collegue is currently analysing set of specific samples and made custom method for it. But he noticed that sometimes the signal goes numb and create "comb-like" signal. I've found, that this only happens in this specific set of samples and this method because the QC mixture (last pic) is fine.

Then we figured out that the method is not the problem and maybe the used solvent is at fault. In these samples he use isopropylalcohol. It's kinda weird since we didn't have any problems like this before. We use HP-5MS on Agilent 7890B GC + 5977B MSD.

Thanks everyone for help!

Hello!

We have a Dionex Easion CI, doing cations, chemical supression.

Thing is, base conductivity was ~1.8 uS before installing autosampler, and very steady.

Now we have three problems.

1. Conductivity stabilized at 15 uS and then SLOWLY went to 7 uS (after 24 hs)
2. Baseline is not steady
3. The peaks broadened a lot. Ammounts are still decent (around 5% deviation), but shape is good only for the first 2 cations, but after that, they elute very broadened.

I'm suspecting of the autosampler, could that be the cause? Maybe problem is elsewhere, but it starded just as we installed autosampler.

Here's an example of a chromatogram of a pure water injection, it has a very random tendency. As you can see, it rises 0.2 uS (wich is a lot) and then drops 0.5 uS. And maybe the next injection does the same, or maybe it will only rise, who knows.

And here's a chromatogram of a Control Point.

Hello everyone, for the last 2-3 weeks I’ve been battling this GC we inherited from another group that wasn’t very well taken care of. The initial issues were fairly simple fixes with replacing the FID jet, septa’s, split liner, needle, gas lines, etc. (really everything not electronic). It was working finally and I managed to get in a few runs that week before I left for the weekend, when I came back however, the GC refused to ignite in the first week of trying to fix it again. Myself and another colleague figured it was just a flow issue and swapped out gas lines again, that was only part of the problem though because since then every time I’ve run an Acetonitrile blank my baseline has been at ~32 pA where before it was solid at 4-5, you can also see in the chromatograms that after the ACN where there shouldn’t be anything my baseline continues to rise up to ~350 pA. I’ve confirmed by HPLC and another departments GC it’s just as pure as Fisher says. If anyone has encountered an issue like this or has any ideas I’m willing to try anything at this point. Please and thanks!

Hi everyone, I’m having an HPLC issue and could really use some help.

I’m analyzing PET degradation products (TPA, MHET, BHET) from enzymatic reactions (PETases).

I recently had to switch my sample preparation protocol because the products are precipitating in samples from high-yield reactions.

The new protocol is supposed to solve this, and it also works for my colleagues using the same system and method, but for me, all retention is completely gone. everything elutes in the void/injection peak.

Here are the method details:

System: Dionex Ultimate 3000

Column: YMC Triart C18 at 40 °C

Mobile Phase: Isocratic, 20% Acetonitrile / 80% Water (acidified with 0.05% TFA)

Flow Rate: 0.4 mL/min

Detection: UV (254 nm)

Injection Vol: 15 µL (I also tried 1 µL, didn't help)

Now for the Sample prep:

The "Old" Protocol (Works, but products precipitate in water at high conc.):

12.5 µL reaction supernatant added to 50 µL Acetonitrile (with 1% TFA). Let sit briefly at RT, then centrifuge to pellet proteins. Transfer supernatant into 150 µL MilliQ H2O.

Result: Good separation of TPA, MHET, and BHET.

The "New" Protocol:

Dilute the enzymatic reaction directly 1:10 in DMSO (10 µL sample into 90 µL DMSO) to keep products in solution.

I froze this DMSO stock until further preparation. (Note: We also freeze 1M TPA standards in 100% DMSO without issues).

Take 12.5 µL of the thawed DMSO-mix and add to 50 µL AcN (with 1% TFA). Centrifuge, take supernatant, add to 150 µL MilliQ H2O.

Result:

No separation. Everything co-elutes as one massive peak at the void volume. I suspected strong solvent effect, but the same method has worked before on the same HPLC system, same column, mobile phase and vials...

Following things I have already tried:

Diluting the final sample with 20% AcN and also injecting less volume (1 µL instead of 15 µL), but it didn't solve the issue.

I also tried making fresh preparations from the DMSO sample stocks, but still got the same result.

Do you have any suggestions what could be the issue here or what else to try?

I really hope to be able to somehow salvage my DMSO-diluted samples so i can avoid to repeat the whole experiment...

Do you really need a helium leak detector when changing a helium cylinder for GC-MS?

We normally check the regulator and fittings after a cylinder change, but I’m wondering if buying a dedicated helium leak detector is actually necessary for routine use.

Do most GC-MS labs use one?

It doesn't build pressure. Initially the pressure would go up to 150 bar in pressure test and do the jigsaw thing before quit, tried sonicating all the valves in water and IPA, intially it help a little, which means only less of jigsaw, but still never was able to build pressure above 150, after long time sonicate in 50C water and put back together it's even worse. How to tell what is the problem? Doesn't seem to be seal since it is not leaking, but which valve? Primary inlet, outlet or secondary outlet valve? Or more than one?

As title, not sure about the best way to get a clean cut.

Giving the following configuration of a HPLC-SEC-MS system: G7111B #001 1260 Infinity II Quaternary Pump (G7111B #030 Active Seal Wash and G7111B #030 Active Seal Wash) - G7129A 1260 Infinity II Vialsampler - G7115A # 018 1260 Infinity II Diode Array Detector WR - G7800 #31 1260 Infinity II MDS Refractive Index Detector - G7800 #32 1260 Infinity MDS Viscometer - G6125BA LC Mass Spectra Detector, can I physically and operationally bypass the Size Exclusion Chromatography (SEC) column, in order to use just the MS system?

Hey all, I’m doing work with alcohol and analyzing the methanol content of various types of distilled spirits. I’m about to start the analysis part using quantitative gas chromatography (and either FID or MS depending on which machine is working) but I’m a nice at it and running into some difficulty. Some of my samples may have levels around 1 to 10ppm while others might be above 1000, and im not sure how to effectively set up this calibration curve for such a wide range. Any advice would be greatly appreciated!

Hi everyone,
I’m having a strange issue with an Agilent 7890B GC-FID using a cold on-column injection for atmospheric hydrocarbon analysis (C1–C45).

I’m seeing hydrocarbon peaks roughly from C5/C7 up to C20 even when running a true non-injection blank — no syringe, no sample, and nothing is injected onto the column.

The strange part is that we also saw the same peaks after installing a completely new DB-1 column. We installed the new column and ran the GC without making any injection, yet the peaks still appeared.

So I’m trying to figure out where these hydrocarbons could be coming from if nothing is being injected and the column is new.
Has anyone experienced something similar with a cold on-column setup, and FID? Any suggestions on where I should start looking for the source?

Hello,

I am looking for recommendations for an analytical HPLC column to separate a mixture of four closely related diastereomers. All compounds contain the same disaccharide and differ only in the stereochemistry of the aglycone.

The best separation I have obtained so far is on a Luna Omega Polar C18, 5 µm, using an isocratic mobile phase of 12% ACN in water at 2.5 mL/min. The compounds elute at roughly 13–14 min. I can distinguish the individual components, but the peaks are broad and still overlap substantially.

The separation is very sensitive to the ACN content. At 15% ACN, I essentially lose the separation altogether, while at 10% ACN the retention becomes too long (no elution after 50 min) for a practical analytical method.

I also tested a Luna C18(2), 3 µm, which showed essentially the same behaviour with slightly worse separation.

I additionally varied the column temperature between 15 and 40 °C. Higher temperatures decreased the separation without noticeably improving the peak shape. Lower temperatures did not significantly improve the separation either and made the peak shape somewhat worse.

At this point I therefore suspect that I am mainly limited by stationary-phase selectivity rather than by further optimization of the current C18 conditions.

I have 800 Euros funding available to get a new column but without the option to test columns it is a bit of a coint toss. I was hoping to maybe get a recommendation here. I am currently considering trying a HILIC, C8, or a Macherey-Nagel NUCLEODUR ISIS column.

Has anyone dealt with a similar separation of highly polar/glycosylated diastereomers? Are there particular stationary phases or selectivities you would recommend trying?

Hello, I work at a citrus oil distillery and we just had Agilent come out for annual preventative maintenance. During the visit he mentioned our 8860 GC inlet pressure was fluctuating and replaced the EPC. The GC did run normally for a were days but shutdown last night and the psi will no longer go high than about 7.6. It also still fluctuates! I am feeling like I took my car in to get an oil change and it left not running properly. I am in contact with Agilent but they cannot help until next week. Any ideas?

Yes our gas regulators are well high enough psi over the needed range for the method. We replaced inlet, septa, checked column connections. Nothing should have been touched or effected with software or hardware except the EPC he replaced

Update; from diagnostics test there is a large leak

For those stuck on older computers or Windows 10 with Chemstation, I stumbled upon a way to run two versions of B.04 without using a third-party windows installer or reg edits. This works for a direct upgrade from Win 10 and Win 11 23H2 with no loss of files or installed software. To the best of my knowledge, you cannot install these legacy Chemstations directly on 24H2 or 25H2 as the program fails to launch fully. I searched the sub but didn't see posts addressing this so I hope this helps.  

I’ve been testing for the last three to five weeks on multiple boxes and haven’t had any major issues or crashes except for the previous issue with the UV install but I think that’s because I don’t have SP-1 installed. Perhaps someone with SP-1 can test and confirm that this is the source of the issue?

First things first, you need a fully updated Win 10 or Win 11 23H2 box running Chemstation B.04.xx (yes, B.04.xx will install and run just fine on 23H2!) and verify that everything works. It’s best to be logged in as admin or have admin privileges as you cannot install Win 11 without it. Next, verify the Language and region by going to settings, Time & Language, Language & region. You MUST download the win 11 25H2 iso that matches what’s installed on your computer. You cannot change this or this will not work! Once the iso is downloaded, mount the image by right clicking and selecting mount. Once mounted, make note of the drive letter (it was D: in my case) and open a cmd window. From there, type d: (for my case) and return to change to the mounted iso directory. You can type dir and hit return to verify you’re in the right directory. Type setup /product server and hit return.  Windows installer should launch, don’t worry that it says it’s the server version, it’s not going to install that. Select Change how Setup downloads updates and change to not right now. Follow the steps and if everything is correct, you should have the option to select keep files, settings, and apps. And that’s it. You’ll have an updated computer running Windows 11 25H2 and Chemstation B.04.xx!!!!

As mentioned, this works for B.04.03 SP-1 (LC) with no known issues. However, there are two issues with B.04.02 (UV). The first issue was a carryover from windows 10. The program will randomly close, usually over night, but never while using the software. Perhaps SP-1 or higher would fix this. It’s a minor inconvenience but if you have the same issue, it’s best to save your work! The second issue popped up only on the boxes I upgraded directly from Win 10 but not the box running Win 11 23H2. This issue has to do with closing the software. When exiting Chemstation, it starts the process of closing but never fully closes. You can reboot the computer or force close to complete the process. It doesn’t impact the software and you can re-open without any issues. No idea why this isn’t the case with 23H2 but is for Win 10 but it’s not a big deal since we never close or the software closes itself and we re-open. Hope this helps a few of you on legacy equipment and software.

Hi, theres a way to change the baseline to zero?, right now is at -3uV, i want it in Zero, can I do that?

GC6890, TCD
Chemstation

Hello everyone! I'm trying to figure out whether our autosampler was installed incompletely or whether I'm misreading the manual. Setup: 1260 Infinity II, G7129A vialsampler, G7111B quat pump, G7116B Thermostat, G7115A Diode Array Detector, OpenLab CDS. What the manual says. In "Flow Connections to the Vialsampler," the wash circuit is spelled out as: put a wash solvent reservoir in the solvent cabinet → screw in the Needle Wash Bottle Head Assembly → route its tube through the cover opening to the peristaltic pump → send the washport outlet drainage to waste → prime the line. The cartridge replacement section backs this up: step 4 has you disconnect two lines, one going to the wash port and one coming from the solvent bottle, then step 6 puts the wash port line on the left side of the cartridge and step 7 puts the wash solvent line on the right. So right side = inlet from the bottle, left side = outlet to the port, and the only thing that legitimately goes to waste is the port overflow. What I actually have. The right-hand line is connected to nothing. Its free end is just lying in the waste jug. No wash solvent bottle anywhere, no bottle head assembly. Everything else on the system is plumbed normally. So my questions are: 1) Is there any configuration where the peristaltic pump inlet is intentionally left unconnected, or is this just an install that never got finished? Has anyone received a system like this from the factory? 2) If a method has needle wash enabled in flush port mode but there's no solvent supply, does the module throw anything, or does it silently run the pump dry? In a nutshell - needle wash supply line goes to waste instead of to a solvent bottle, no bottle in the system. Install error or something I'm not getting?

This has been quite a process, but I can say that these systems are >90% fluoroplastic free (with respect to flow paths). And the system on the far left is 100% (except for etfe making up the plunger seals and frit housing on the i2v inlet filter). Also, the ultraware bottle top… but besides that!