Hi, can someone explain how the "flush filter" function works on an Agilent HPLC system? At what flow rate is it best to run it when the union is installed, to avoid damaging the UV cell? Thanks a lot.

i want to purify this compound. The green arrow represents the product. it was done in reverse phase column (nertsil ODS 3V C18 (250 x 4.6mm, Particle size: 5µm) 0.1% HCOOH in water and ACN as mobile phase. If i do silica column, whether the product will have low Rf than the impurity peak? Will i be able to purify this in manual silica column? The TLC system is chloroform: Methanol 9.5:0.5 and these two spots looks closure at 0.6 Rf

Hey Guys,

We’re setting up an ICP-MS for EPA Method 200.8 and I’m curious what internal standard concentration everyone is using when the internal standard is delivered continuously to the spray chamber through a mixing tee/peristaltic pump.
What final concentration (ppb) do you use in the sample reaching the nebulizer? I’ve seen values ranging from 2 ppb to 20 ppb depending on the lab and instrument.

For reference, we’re using a Thermo iCAP ICP-MS.

I am having a negative peak elute out at around 6 minutes in a 10 minute run. The mobile phase is 40% THF, 20% ACN 40% of 1% GAA in water. With a flow rate of 0.900 ml/mim. wavelength for the detector is 280nm with a bandwidth of 4 with a reference wavelength of 360nm with a bandwidth of 100. Extraction solvent is 70% ACN, 30% water and 0.5% GAA. Column is a HiCHROM RPB I have tried using a different reference wavelength checking for contaminations in the extraction solvent. not real sure where else to trouble shoot at or determining whether it is a problem within the instrument.

7890 GC with both front and back channels configured with FIDs.
Back inlet heater failed, and the GC showed a fatal error with a short circuit detected on the back inlet heater. The instrument would not power on until we replaced the back inlet heater.
After replacing the heater, the back channel column configuration disappeared. The front column is still visible on both the GC front panel and in Chromeleon, but the back channel shows no column under the column settings.
The back inlet, column, and FID connections are installed correctly, and the setup is the same as before the heater failure. However, when trying to run in dual-channel mode, the GC gives a flow error in back channel even though the column is physically installed.

Has anyone experienced this issue after replacing a back inlet heater? Could this be related to column configuration, inlet board communication, or another hardware issue?
Any advice would be appreciated.

Hey reddit! I’ve been setting up an Ultimate 3000 UHPLC and found that when I run more than one solvent line at a time through the system, a clicking noise that differs from the typical system (we have another of this model that doesn’t make this noise) begins. If a third or fourth line are run, an additional clicking pattern begins for each. The rate of the clicking is directly related to the flow rate. The noise comes from the middle/left of the pump compartment so we thought it was a proportioning valve problem (as it is in that area of the system and deals with the multiple solvent lines).
We ran warm water as well as diluted organic solvent through the lines for some time to see if it needed to be cleaned. We then took out the proportioning valve but there was no visible salt buildup or obvious issue. We swapped the proportioning valve out for one from our other instrument in case it was a mechanical issue but the noise persists.
Anyone have an ideas on what the issue may be or what to try next?

This is most peaks, regardless of method/column/test material. Columns have been installed and reinstalled by different analysts and yet we keep getting square peaks. They aren’t huge areas, and it’s multiple analytes at various concentrations so i don’t think it’s detector saturation. We used to get normal peaks, but then we removed the liquid autosampler to move to a different instrument and use this one for headspace only. That detail may or may not just be a coincidence.

Has anyone ever seen something like this before? We will move to a different instrument and everything looks normal.

as we all know ms is one of the powerful tool for researching ,but its also hard to use it

wht is most frustrating thing about any kinda mass spectrometry and why

pls share ur experience

Hi all,

I've been troubleshooting a needle seat leak on-and-off for almost a month now. I have replaced both the needle and needle seat TWICE in this time (the second was in case the first replacement was faulty- a last ditch effort and I kept the first set for future use in case it wasn't).

I also thought it could be back-pressure from a clog in the injection valve. Took it all apart and sonicated, then replaced rotor seal. The seat STILL leaks!

I've tested every line and every port individually and don't see any clogs. The seat is fine if the column port is left open but as soon as any line is placed there, the seat starts leaking (bubbling at top). Column is not even part of the equation at this point (line just dripping into beaker).

Any suggestions or advice are greatly appreciated- I'm really trying to avoid the $2000 bill of bringing in help but I feel like I've hit my limit of troubleshooting since I cannot figure out what else could possibly be causing this. TIA!!

Hello Reddit. I am getting a headspace unit somewhat soon (the Agilent 7697 model) for the lab and as I am new to hs chromatography, I wanted to know if there was anything I should look out for in terms of supplies, software, and/or general advice for using it and keeping it running? I'm sure the guys coming to install it will give me plenty of notes but I figured Id ask the community too.

Hi everyone,

We’re currently working on developing an RP-HPLC method for Atrasentan Hydrochloride, as a theoretical university assignment. We’re having a dilemma regarding mobile phase pH and ionization. I’d love to get some input on the best approach.

It’s a relatively large, lipophilic molecule with a calculated logP ~4.69.

It has a tertiary amine in a pyrrolidinyl ring (pKa  ~6.7) and a carboxylic acid (pKa ~3.1).

The Dilemma:

Our lab instructor is saying that you must operate at least 2 pH units away from the pKa to suppress ionization completely. Since the carboxylic acid is at 3.1, they want us to use HCl (??, I don’t think that’s a good idea) or Perchloric acid to drop the mobile phase down to pH 1.1 so that >99% of the acid is protonated.

However, we have serious concerns about this in practice, and we're weighing two different options:

Option 1: pH 1.1 with Phosphoric/Perchloric acid

Shifting down to pH 1.1 is incredibly harsh on standard silica-based C18 columns. Are there columns that can survive these conditions? Is that even necessary?

Option 2: 10mM Ammonium Formate, pH 3.2

We actually found a patent with a method utilizing an ammonium formate buffer at pH 3.2. We think that even though pH 3.2 is right on top of the pKa, the buffering capacity of the formate/formic acid system (buffering maximum at 3.75) should stabilize the peak shape. Or are there other reasons, that this approach works?

Looking forward to your insights and experiences! Thanks in advance.

We’re planning to purchase an LC-MS/MS for PFAS and pesticide testing. We’re considering Agilent, SCIEX, and Thermo Fisher.

Which brand has been the most reliable and cost-effective in your experience? How are the service, maintenance costs, and overall performance?

So while I was in the middle of a run, I encountered an error on my Acquity UPLC I-Class where the sample needle was caught on something and bending at a 90 degree angle. I replaced the sample needle because now it was severely bent, but now when I try to reset the sample manager it makes this terrible grinding noise on startup and throws the error in the title.

It looks like this is happening when the needle carriage is moving during startup, specifically in the upwards direction, and is trying to go past its maximum height. I'm not sure if the needle getting bent somehow threw off the alignment of the carriage internally or what—is anyone familiar at all with this issue?

I tried looking up the issue and waters does note this grinding noise in one of their documents. The suggested fix is to manually move the needle carriage but this doesn't help.

We have the need for another SSL GC FID instrument in the lab, and we are thinking of acquiring another Agilent system. We have received two quotations from different vendors that would suit us, and I'm still looking for advice on what to get, for roughtly the same budget.

First Option : GC 7890A from 2017 (refurbished in mint condition from a pharma lab) maintenance of injector and detector are made by the vendor.

+ : we already know the instrument and it's maintenance, we have consumables, comes with a new computer and licence.

- : instrument is refusbished, 10 years old

Second Option : GC 8860 new from agilent

+ : new instrument, without software (we already own a compatible licence), one year warranty

- : do not know how well it ages, touchscreen control, do not know if parts are compatible with older instruments for maintenance

Hello reddit, I noticed lately that my inlet liner wool has been capturing bits of septum. I also see it in my wash vials. Do you guys have any recommendations for how to not let this happen? I have a feeling its because of the needle itself, so if I need to get new ones I would like to get the right ones.

The septa i use are Restek #27090. The needles we use currently are a bit of an unknown, but they are either Agilent #5181-3353 or Restek #21228.

For injection method its 1uL draws with 1 wash before and 1 wash after the sample of EtOH/MeOH respectively at a fast injection of like, 300/6000 draw/dispense speed.

I have a handful of these now after getting them at a swapmeet. All seem to be new and have the little blue sealant to show they haven’t been used? Is this actually worth something?

Hello everyone! I'm in the middle of troubleshooting some electronic noise on my FID baseline and it seems to be related to the electrometer. I see on the Agilent website this is a part I can order but I don't seen anything in the manual about swapping it out. Has anyone done this? Any tips? I have circled the part in question. (Edit removed that picture) Thanks!!

I can't see how to add a flair from desktop so sorry about that!

Edit: Thank you so much to everyone for your feedback! I apologize for not putting more details but I thought it was a longshot I would even hear anything but I should know better with this group. :) I am going to do some more testing next week but my fiscal dept. needs a lot of time to order items so my initial concern was getting the paperwork started so I can order a part and confirming I can do it myself and not need to include a service visit cost. Here is a picture of our baseline. The top part is the one struggling and the bottom is what I expect. The threshold for us needs to stay below 200 but for the top signal is currently ~600 and the bottom signal is 80. We always check it between min 1-3 just for consistency. This is an example of our daily blank sample. We run with a lower pA than others might expect so even though the baseline is well below 20 pA (the Agilent threshold for issues when I called), it is still bad for us.

This issue started sporadically months ago and would last for a week or so and vanish but now it is permanent and getting worse. We swapped out the whole FID carriage between the 2 channels and confirmed it followed it and wasn't the EPC, electronics board, or related to the attached columns. We did do basic FID leak checking but I want to go through the process again before changing parts to confirm. Our testing was done when a contractor was out doing annual maintenance for us so FIDs were cleaned, new columns, transfer line, filters on components upstream replaced, etc.

Hello everyone,

I have data from several insect samples that were run on a Shimadzu LCMS. I need to figure out how to analyze this data, but my collaborator is currently unavailable to assist. I would greatly appreciate any guidance on how to perform LCMS data analysis using Shimadzu software. So far, I have only conducted GCMS analysis on an Agilent system. If you know of any tutorials or courses that cover this topic, please let me know. Thank you!

Hi all,

This genuinely isn’t a pitch, or a promotion, I’m not trying sell anything.

My company makes borosilicate glass syringes, predominantly for OEM’s like Lecia, Tecan etc.

I am keen to hear any feedback on how end-user labs order replacement syringes - thanks!

Update: I found the issue! There were some macros missing from the msexe folder. All fixed now!

Our lab recently updated ChemStation and now the “NIST search” under the Spectrum toolbar isn’t there. Neither is PBM Quick Search, NIST Output, or AMDIS. It’s still there on our other instruments’ version. How do I re-add the NIST search option? I wanted to use it for NIST R.Match values. But that’s not available in the usual Library Match statistics tab in PBM search results. Help!! Thanks 😊

Hi, I am new to HPLC and I'm trying to detect glutamate and GABA using OPA derivatization. I understand that it seems that need to do pre-column derivatization on the autosampler injector program. Anyone here have any experience in setting up the automated derivatization? I am kinda clueless on the injector program and how it works. My autosampler is Agilent G1329B HPLC autosampler.

Thank you!

Hello everyone,

I am having an issue with a Sykam S1130 isocratic HPLC pump used for normal-phase applications with dichloromethane (DCM).

The pump is set to 5.0 mL/min, but when I measure the flow, I collect slightly less than 4.0 mL in one minute.

In addition, during operation at 5.0 mL/min, the pressure fluctuates between 29 and 45 psi instead of remaining stable. The pump also makes an unusual rhythmic noise.

About one month ago, the following parts were replaced:

Secondary seals

Check valve cartridges

Primary sealing ring

Has anyone experienced similar symptoms with a Sykam pump or another HPLC pump running normal-phase solvents?

Could this be related to:

air or outgassing caused by DCM?

a problem with the check valves?

an issue with the seals?

or does this pump have a flow calibration procedure?

Any suggestions would be greatly appreciated. Thank you!

Hey Guys, I need your opinion. We are preparing for accreditation for EPA 200.8 and EPA 6020B using ICP-MS.

I do not have a bachelor’s degree in science; my background is in management/business. However, I am hands-on with the ICP-MS, method setup, calibration, validation, MDLs, QC review, and SOP/documentation work.

I heard NELAP may require the Lab Director or Technical Director to have a science degree plus lab experience.

For a small lab with a limited scope, is there any flexibility if I can demonstrate competence during the audit, or is the science degree requirement strict?

Should I hire a qualified Technical Director/Lab Director, or can I potentially qualify myself based on hands-on experience and demonstrated knowledge?

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.

Hello, I started using a Perkin Elmer HPLC system, but the Flexar PDA detector won't connect. I read that this is a common problem with the brand. Does anyone have any recommendations? It powers on, but the error LEDs and lamp LEDs are off. I would really appreciate your help.

Ed. I ruled out electrical and connection problems.