r/CHROMATOGRAPHY

Hi everyone,

We are planning to purchase an Agilent LC/MS/MS system for PFAS testing and wanted to get some feedback from people with real experience.

Is the Agilent 6475 Triple Quadrupole LC/MS/MS strong enough for EPA PFAS methods such as 533, 537.1, and 1633?

Or is it worth spending significantly more money on the Agilent 6495D because of the higher sensitivity and performance?

We are trying to understand if the 6475 is enough for routine compliance work, or if the 6495D is a better long-term investment for PFAS testing.

Any feedback from labs running PFAS methods would be appreciated.

Thanks.

New to the industry and just trying to get some information.

Hi.

Waters UPLC Aquity H Class.

Last post, yesterday, I received many help and I took everything into consideration and wanted to share results. i'm very new at this. Problem is: high and unstable pressure of the system. Always rising Here we go with today's tests:

Tests 1, 2 and 3: Replacing column with a fitting, and purging 4 lines with MeOH, and then monitoring pressure with flux increments until 1 ml/min. Test 2 was the same but with ACN. Test 3 same but using working mixture: solvent A: 0,1% formic in water and solvent B: 100% ACN. The system runs in a 70:30 mixture of A and B. below picture with ACN.

https://preview.redd.it/g5qhe4cjshah1.png?width=1280&format=png&auto=webp&s=0dc230cd0c97db6417caa38f94e8d0d09860d629

Pressure is steady, reaching it's value quickly too in all cases and remaining steady. difference is: in Test 3 there is a "clack-clack" coming from the valve which receives all 4 solvents tubings. it's 2 noises, seems like an "open-close" of a valve, and it accompanies the bomb cycle. 1 bomb cycle = 2 "clacks". seems quite normal since it's mixing A and B, but I'm not used to the noise, maybe it's a bit noisier than normal.

Well, that being said, the system seems to perform bad or well?

For us is well, so we proceeded to insert the column, which made things don't work quite well: Pressure stills rising. Using that 70:30 mixture, we slowly went to work flux, which is 0.4 ml/min. Pressure has been arround 10600 and has a delta of ~50, without stabilizing ever, and again slowly - slowly- rising. in 15 minutes of writing this, now is 10800 psi.

https://preview.redd.it/bsec7qmlshah1.png?width=1280&format=png&auto=webp&s=66c939d18b95315f4253e653faa52243a131c1e7

Could we say this is a column issue, or would that be a rushed and erratic conclusion?

extra!

in the test without column, we noticed that the system pressure has a little oscilation (around 10 psi) when pressure is below 600 psi. is that normal? after 600 psi it seems to accomodate with an oscilation of 2-3 psi only. it does it regardless of the solvent. it's perfectly coordinated with bomb sounds. a picture here:

https://preview.redd.it/d5wlnewgshah1.png?width=1599&format=png&auto=webp&s=d4cd962c8303a9320cf13dfd8e97ee3d2232ee4d

Thanks very much!!

Hello there. I'm completely new at this.

At my lab, we have a Waters Aquity class H, and run a mixture: 70 0,1% formic in water(solvent A) : 30 acetonitrile (solvent B). flux 0.4 ml/min. C is methanol.

The UPLC has been used previously by another branch of the company, and it was installed here a month ago, and validated by a technician. but unfortunately, last week we saw this:

1. Pressure with 70:30 is higher than usual: +12000 psi at work flux, where it should be around 8000.
2. Pressure with 70:30 mixture is unstable, and seems to be always slowly rising. whilst with 100% acetonitrile, it reaches a value and remains very steady. for example, at 0.1 flux, it achieves 900 psi in 30 seconds, while using 70:30 goes to 2600 psi and starts going up... it can go 15 minutes and still rising.

we purged the column with acetonitrile a lot, also backflushed it in case we contaminated it, and no results. Finally we used another column. But the same replicates in both columns... which is very weird for a novice like me.

We did some leak tests, surprisingly solvent A (water with 0,1% formic) passess accumulator and primary tests. But B and C pass only the acumulator test, not the primary. Leak rate is 460 nL/min and 213 nL/min could that test have something to say?

I'm currently sonicating the check valve in methanol, thanks to a suggestion of laboratory boss.

please let me know if there is information I'm missing in order to clarify. best, thanks in advance!

Does your method go over 700 bar (10kpsi)? Do you really need a >700 bar LC system?
I find very unnecessary how LC vendors do high brand marketing regarding how high their LC pressure can reach. I believe there are no many methods where going that high in pressure might be actually useful

I'm new to the lab and have a good academic knowledge about the chromatography but the issue is the software

My lab have agilant chemstation and open lab

In addition to that waters system (empower)

I there is any book or detailed artical i could read that could ease out my work

I am capable of runing singles and sequences but i need more information about the integration and calibration

Greetings fellow nerds!

I am playing around with our Agilent GC 7890B (both an FID and an MS) functionality to do layered injections, particularly for in-port TMS derivatization (currently experimenting with different reagents). So far, I like the results. However, one notable problem is the septum on the reagent vial cap. It's a vial with a 200 uL insert containing 100 uL reagent. With our usual Red Rubber // FEP 1.0 mm caps, eventually, strong polysiloxane peaks appear in chromatograms. Which is interesting, since I can usually inject the same sample near endlessly without this happening. I also tried aluminium septum caps, but predictably, the reagent evaporates overnight.

I wonder how people deal with this except by replacing the caps every couple injections. During long sequences that go on for days, this seems awfully impractical. Are there caps that are better suited?

Thanks to all in advance!

Hello,

We were graciously given a Thermo/Dionex PDA-3000. However, I can’t complete its configuration because it gets stuck at driver initialization.

We are technically using SII for Xcalibur 1.2 rather than a full Chromeleon installation. It will grab the serial number from the module, so I know there is at least some communication.

Here are things I have tried:
Restarting module
Removing stack but keeping just the detector
Plugging the USB from the detector to the computer directly
Going to SII for Xcalibur 1.5

Things I am going to try Monday:
Installing SII for Xcalibur on my laptop and trying
Try installing the detector on a colleague’s full Chromeleon 7.3 install

The firmware is 2.0.0, so I am wondering if maybe it is a firmware issue?

Can anyone chime in with experience or something i haven’t thought to try?

Thanks!

A few month ago one of our Agilent G1329B autosamplers started to show short unintended power cycles with a duration of about 10 seconds. In the beginning this happened once every about 3 month, now about one to two times a day.

I read out the diagnostic buffers using labadvisor. In the SwitchOnTimeHistory of the module G1329B the power-on events of this unintended power cylcles do have entries like

"timestamp,2,0xd102", whereas the power-on events of regular manual power cycles have entries like

"timestamp,1,0xd102". Does someone know what this code 2 mean? Other modules of the system do not have this problem. We pluged the system in a UPS and the problem still persisted. If a sequence is running it stops with an error because the other modules loose communication to the autosampler. The events happen even if the system is in standby.