ISOGEOCHEM List

Re: two different topics: 1.Anti-vibration pads. 2.Regulator/gas station

2026-06-05T10:40:33-07:00

Hi Julia-

Getting a regulator with check valve in the CGA fitting or installing a
pigtail with check valve have eliminated any need I have had for purging
regulators. With these in place you have a short amount of time, perhaps a
couple minutes to change a tank without the regulator loosing excessive
pressure or introducing noticeable contamination in your carrier lines. I'm
typically more concerned about adjusting to backgrounds from a new tank
compared to room contamination. In this case, it's good to run your
downstream devices including branch lines at full flow for a bit, and
allowing some [...]

European Dendrofieldweek EDF 2026, Bardonecchia/Italy

2026-06-05T14:04:18+00:00

Dear colleagues and friends
This announcement is for those interested in tree rings.

We are happy to announce that the 36th European Dendroecological Fieldweek (EDF) will take place from Fr, August 28 to Fr, September 4, 2026 in Bardonecchia, Italy, in close co-organisation btw the Dendrolabs of WSL and the University of Torino. Details and the registration link can be found here https://www.wsl.ch/dendrofieldweek [...]

Re: two different topics: 1.Anti-vibration pads. 2.Regulator/gas station

2026-06-05T06:08:30+00:00

Hi everyone,

And thank you all for the invaluable information and so many ideas.
As always, this group is full of wonderful people who are generous with their knowledge.

Have a nice weekend and best wishes,
Julia

Re: two different topics: 1.Anti-vibration pads. 2.Regulator/gas station

2026-06-04T12:23:14-05:00

Hi Julia,
Another option is to use a thee way valve as suggested previously, and keep
a Trajan/Agilent "big universal trap" downstream from the 3-way (toggling
the valve to purge the regulator volume isolates the trap from ambient
air). The trap volume will keep the instruments fed with helium long enough
to swap the helium tank. There is no air slug in the line if you use this
setup. [...]

Re: two different topics: 1.Anti-vibration pads. 2.Regulator/gas station

2026-06-04T10:12:18-07:00

I second Paul’s enthusiasm for switchover manifolds. It has been some time in the past, but I bought just the switchover regulator from Tescom. The rest of the assembly; pigtails (McMaster), and other fittings independently of the regulator were bought from other vendors. it worked out to about half the cost of a packaged system that vendors, like Prostar, offer if you assemble it yourself. [...]

Re: two different topics: 1.Anti-vibration pads. 2.Regulator/gas station

2026-06-04T16:01:40+00:00

Julia,

I'm a fan of switchover manifolds (although a bit of an investment): you can hook up two tanks and the system will automatically start drawing from the second tank when the first is empty. Ours also has vent valves for each tank so that you can clear the line after hook up. [...]

Re: two different topics: 1.Anti-vibration pads. 2.Regulator/gas station

2026-06-04T11:15:21+00:00

Hi Julia.

We have some instruments installed on pneumatic mounts, because we had a time in the past where contractors were using vibration rollers. We also have a quarry next door that blast once or twice a week. They are similar to these:
PLM3 | Fabreeka M12 Anti-Vibration Mount, Pneumatic | RS<https://uk.rs-online.com/web/p/anti-vibration-mounts/0688492?cm_mmc=UK-PLA-DS3A-_-bing-_-PLA_UK_EN_Catch+All-_-Mechanical,+Fluid+Power+%26+Tools-_-688492&matchtype=e&pla-4574999185500285&cq_src=google_ads&cq_cmp=554644865&cq_term=&cq_plac=&cq_net=o&cq_plt=gp&gclid=c2c40259993e1ce76e096878c433b733&gclsrc=3p.ds&msclkid=c2c40259993e1ce76e096878c433b733> and are pumped up with a regular foot pump to around 2 bars once in a while. [...]

LGR N2O analyser spectra fit

2026-06-04T09:58:35+02:00

Dear all,

I am measuring N2O isotopes using an N2OIA-23e-EP and am primarily
interested in the δ15N-bulk measurement. The samples are air samples
collected from incubation experiments in which 15N-labeled NH4NO3 was
applied.

Before analysis, the sample gas passes through a CO2 scrubber (Ascarite)
and a water trap.

*Issue:*
When I measure samples with a natural isotopic composition, the spectral
fits for both δ15Nα and δ15Nβ are reasonably good (see attached figure).
However, when I measure my 15N-enriched samples, the fitted spectrum
deviates noticeably from the measured absorption spectrum (see figure). [...]

Re: two different topics: 1.Anti-vibration pads. 2.Regulator/gas station

2026-06-04T09:14:18+02:00

Hi Julia,

1. Our Delta V is still on it's wheels and happy. The laboratory does have an antivibration insert built into the floor. We were fortunate that we had the option to build up the physical space before the IRMS got moved in. There are two exposed bolts to hold the IRMS in place, these were never put down and suspect that they transmit any floor vibrations. [...]

Re: two different topics: 1.Anti-vibration pads. 2.Regulator/gas station

2026-06-03T23:13:45+00:00

Dear Julia,
We use what the hardware store calls “piano cups” under the wind-down IRMS feet – those little rubber cups that prevent the piano from crushing the carpet. Being a Pacific rim country, I should really add seismic restraints too – we’re required by regulation to have them on domestic hot water cylinders after all. [...]

Re: two different topics: 1.Anti-vibration pads. 2.Regulator/gas station

2026-06-03T20:48:42+00:00

Hi Julia, our Thermo IRMS all rest on adjustable threaded bolts that look like they are part of the instrument. For our 253, tapered plastic feet are attached to the bolts, which also appear to be stock. All our Delta V plus' only have bare bolts and those are resting on what, somewhat fittingly, looks like hockey pucks. I doubt those came with the instrument, but who knows. Either way, they held up well for over a decade. As for the purge valve in the carrier line, we patched a Swagelok T into the carrier gas line downstream of the [...]

Re: two different topics: 1.Anti-vibration pads. 2.Regulator/gas station

2026-06-03T10:09:54-07:00

Hi Julia,

I never thought about it until now. The Horizon has four ~8 cm diameter
screw type leveling feet with thick rubber pads. All part of the
instrument. Meanwhile the 253 has a metal frame that rests directly on
the floor. And it was designed that way.

Our helium regulators have a check valve that will maintain pressure for
longer than it takes to move the connector to a full tank, but a sip of
air is unavoidable. [...]

Re: Use of a H2 generator

2026-06-03T16:18:21+02:00

Hi, Christian

1I also had some issues last year with my hydrogen.
The cylinder was from Air Liquide, with a delta of around -800 per mill.
I used a hydrogen generator to test it out.
Similarly, I observed a delta per mill close to -800. But this can be
adjusted by adding deuterated water to the tank to achieve the desired
enrichment.
However, since production isn’t constant, I noticed a very strong drift
over 24 hours during my experiments. Therefore, it is not compatible
with my TC-EA-conflow3 and Delta V Plus system.
After some research on Isogeochem website, I found [...]

Use of a H2 generator

2026-06-03T11:41:58+00:00

IFE Public

Dear colleagues,

Do any of you have experience using a hydrogen generator (electrolysis-based) for production of the working/"reference" gas for hydrogen IRMS work? In particular, how rapidly does the produced H2 change its isotopic composition and is it stable enough for use during one analytical sequence or would we expect drift from sample to sample? Using H2 in our lab is becoming more and more difficult due to increasingly expensive HSE regulations, and switching to a hydrogen generator would solve many of the problems related to high pressure H2. I would be grateful to hear if anyone has [...]

two different topics: 1.Anti-vibration pads. 2.Regulator/gas station

2026-06-03T02:57:20-04:00

Hi everyone,

I need help with the following two topics:

- Our IRMS is currently mounted on wheels, and the engineer who came to carry out preventive maintenance told me that this wasn’t ideal. He recommended that I replace the wheels with the IRMS’s feet and add some anti-vibration pads.
Does anyone have these and could tell me where to buy them?

- I also need information about a gas regulator or a regulator station with a purge valve, to remove the air that enters when replacing empty cylinders with new ones, avoiding getting air in your line.

I would appreciate any information you can provide.

Thanks and best wishes,
Julia

Open position: Postdoc in isotope biogeochemistry

2026-06-03T06:09:48+00:00

Dear ISOGEOCHEMers,

We are looking for a postdoc in the METHIR project: https://jobs.unibe.ch/job-vacancies/postdoc-in-isotope-biogeochemistry/8a585c0d-3c72-4bf1-80f5-be921f4e9ec7

The project: Isotope ratio measurements are a key part of our efforts to understand sources and sinks of the major greenhouse gases CO2, CH4 and N2O. Harmonised and standardised field calibration and measurement methods are required to support isotopic measurements in networks such as the Integrated Carbon Observation System (ICOS). The METHIR project is a major European effort aimed at improving field isotope ratio measurements harmonisation and calibration, with direct linkages to current measurement networks. [...]

AW: [ISOGEOCHEM] AW: [ISOGEOCHEM] 4-Port Silflow Alternative?

2026-06-02T14:51:38+00:00

Jack’s approach of course, sorry.
Seth, the T-piece set up does not change the oxidation capabilities (pre-oxidation, seed-oxidation) at all.

Best,
Jens

Von: Stable Isotope Geochemistry <ISOGEOCHEM@list.uvm.edu> Im Auftrag von Seth Newsome
Gesendet: Dienstag, 2. Juni 2026 15:10
An: ISOGEOCHEM@LIST.UVM.EDU
Betreff: Re: [ISOGEOCHEM] AW: [ISOGEOCHEM] 4-Port Silflow Alternative?

Hi All…

Thanks for all of the feedback, schematics, and parts numbers… I have a question for those of you using a “T” or 3-port setup: does this impact your ability to do pre-oxidation or other (longer) oxidation procedures? Looking closely at the plumbing suggests to me that it doesn’t but I [...]

two different topics: 1.Anti-vibration pads. 2.Regulator/gas station

2026-06-02T10:14:56-04:00

Re: AW: [ISOGEOCHEM] 4-Port Silflow Alternative?

2026-06-02T08:52:12-05:00

Hi all,

I didn't realize so many people also did the 3-port modification! I
originally got the idea from Elementar's GC-IRMS design and later noticed
that Thermo's Isolink II C Option (having one a combustion reactor) is
essentially identical to what we all describe.

For the unattached reactor, I do slide it partially out of the GC oven (as
far as a closed Isolink door will allow) to reduce the thermal 'wear' of
unnecessary GC heat cycles. [...]

Re: AW: [ISOGEOCHEM] 4-Port Silflow Alternative?

2026-06-02T13:10:00+00:00

Hi All…

Thanks for all of the feedback, schematics, and parts numbers… I have a question for those of you using a “T” or 3-port setup: does this impact your ability to do pre-oxidation or other (longer) oxidation procedures? Looking closely at the plumbing suggests to me that it doesn’t but I don’t have any experience with using a 3-port setup… [...]

AW: [ISOGEOCHEM] 4-Port Silflow Alternative?

2026-06-02T12:45:53+00:00

Hi everyone,

Similar to Seth’s approach (and maybe to answer Florian’s question) we replaced the 4port after the reactors and the setup (MCD or siltite or whatever) before the reactors (inside the oven) by two valco T-pieces. We do not use Thermo’s welded reactors mainly for financial reasons and to switch reactors we just open the valco connections on both ends of one reactor and re-attach at the other.
In this setup, the 4port is not part of the gas way – this makes troubleshooting much easier. [...]

AW: [ISOGEOCHEM] 4-Port Silflow Alternative?

2026-06-02T08:19:37+00:00

Hi Jack,

I am definitely interested in more details on your alternative setup. Do you just leave the ends of the unused reactor open for doing oxidations / Methane conditionings? I have a residual worry about not sending clean enough Helium towards the instrument while the 4 port valve is in the “wrong” position during those procedures. [...]

Re: [EXTERN] [ISOGEOCHEM] 4-Port Silflow Alternative?

2026-06-01T19:47:51+00:00

We use a valco 3-way union with valcon polyimide ferrules and leave the unused reactor disconnected. It works in our case because we don’t switch between modes all that often.
Dan

On 1 Jun 2026, at 21:15, Natalie Wallsgrove <nw@HAWAII.EDU> wrote:

We just use a valco 4-way union and it works great (after the initial annoyance of leak resolution with the first few oven ramps). Natalie [...]

Re: 4-Port Silflow Alternative?

2026-06-01T11:31:44-08:00

I've also been using a Valco union instead of the MCD. However, I use a
three-way union and I have my facilities folks machine down the big bump /
knob on the union so that it doesn't have as much thermal mass. And they
are waaaaay cheaper. I have found no changes in separation /
resolution with this setup and the connections are far easier to make. It
works with the metal capillary on the stock Thermo reactors as well. [...]

Re: 4-Port Silflow Alternative?

2026-06-01T09:15:50-10:00

Full message available at: Re: 4-Port Silflow Alternative?

Re: 4-Port Silflow Alternative?

2026-06-02T05:07:25+10:00

Hi Seth, I have good experience with GC press fit connectors, they are easy
to use and leak free. There are Y shaped ones that used in series might
allow the substitution of a 4 way manifold. Just an idea. Regards,

Matheus C. Carvalho
Southern Cross University, Australia
Editor for HardwareX (Elsevier)

*Improved open source autosampler for microbalances
<https://www.researchgate.net/publication/370564297_Automated_weighing_in_the_stable_isotope_lab_when_less_is_more>* [...]

Re: 4-Port Silflow Alternative?

2026-06-01T13:26:05-05:00

Hi Seth,

We eventually eliminated the 4-port MCD in favor of a better capillary
solution (Agilent's CFT line) as well as 'dumbing down' the Isolink II to
simplify the flowpath. To do this, we swapped the 4-port MCD for a 3-way
CFT tee (Agilent #G3184-60065) on the GC side and, on the external side,
bypass the 4-port switching valve for a 3-way Valco tee. To swap between
HTC and Combustion modes, the connections are manually swapped. With CFT
connections, a ferrule is permanently swaged onto capillary but can be
connected/disconnected multiple times. This makes the manual swap simple
and is [...]

4-Port Silflow Alternative?

2026-06-01T17:02:29+00:00

Hi All…

Hope all is well… I've been loyally using SGE/Trajan Silflow (MCD) on our GCC-equipped instruments for the past dozen years… Overall, they are reliable but don’t last long when routinely running AA derivatives from plants, fungi, and algae… In addition, they now cost ~$750 USD, a ~40% increase in price in the past few years… [...]

TC/EA GC oven not reaching temperature

2026-06-01T12:34:02-04:00

Hello friends,

We have a TC/EA system and recently the GC oven for the first time is not
behaving. The temperature stopped at 160 C when the set point was at 300C
intended for quick baking.

The resistance is at 200 hm , very similar reading compared to the other
newer TC/EA we have in the lab. [...]

book

2026-05-29T12:23:09+00:00

Dear all,

I am selling several volumes of the Handbook of Stable Isotope Analytical Techniques, Volume 1 and Volume 2, by Pier A. de Groot.

If you are interested, please write to me directly on: ana-voica.bojar@plus.ac.at

Best regards,

Ana-Voica Bojar

2026 Organic Geochemistry Gordon Research Conference and Seminar - Application deadline on July 5

2026-05-29T05:25:21+00:00

Dear colleagues,

This is a friendly reminder that applications for the 2026 Organic Geochemistry Gordon Research Conference (GRC; August 2-7) will be accepted until July 5, 2026. Please apply and register early, as this meeting typically reaches capacity before the deadline.
https://www.grc.org/organic-geochemistry-conference/2026/

Applications from first-time GRC attendees submitted before June 15 will be considered for the Carl Storm Opportunity Fellowship, which provides full registration support. [...]

opening postdoc position at CRPG (Lorraine University, France) - mantle noble gas analysis by IRMS

2026-05-28T13:57:26+02:00

Hello everyone,

I hope this email finds you well. We have a postdoc position opening at the University of Lorraine (CRPG, Nancy) on mantle-derived noble gas analysis by IRMS, as part of a new project funded by the French government ( [ https://pepr-origins.fr/projet/primordial/ | https://pepr-origins.fr/projet/primordial/ ] ). The project will include analytical developments, field campaigns, and noble gas analyses from hydrothermal and volcanic regions to characterize the compositions of various mantle reservoirs and develop new geochemical tools for monitoring volcanic activity. Please find below more details about the available position and please forward this on to anyone who you think [...]

FW: Ph.D. position at ETH Zurich <--> Doctoral position in plant metabolism and stable isotope biology (H-Shifts)

2026-05-28T10:53:44+00:00

Dear isotope community,

<Please do not reply via ISOGEOCHEM list.>
Please circulate the following job posting to potential applicants.
Apologies for cross-posting

Doctoral position in plant metabolism and stable isotope biology (H-Shifts)
https://jobs.ethz.ch/job/view/JOPG_ethz_TGK2F1mbvhUN2rbFCZ
Project description available:
https://gl.ethz.ch/research/pepb/hshifts.html
We look forward to receiving your online application by 1 July 2026 with the following documents:
Letter of motivation
CV
Bachelor's and Master's certificates with complete transcripts
Contact information of 1-2 referees
Please note that we exclusively accept applications submitted through our online application portal. Applications via email or postal services will not be considered.
https://emea2.softfactors.com/job-opening/rgum-TGK2F1mbvhUN2rbFCZ#!/?lang=en
The desired starting date is no later [...]

Transport of a Thermo Delta V

2026-05-27T06:49:53+00:00

Hello dear Isogeochemists,

If someone has insights how to transport a Thermo Delta V I'd be very pleased to gather this knowledge. Our lab has the opportunity to get a used one but the transport is on us. I'm familiar how to move a MAT 253 by removing the magnet and so on but I've never touched a DeltaV. I know that everything is smushed into the detector's box but that's all.
So I someone can help us out here I'd be very grateful. [...]

Query regarding SPM sampling volume for CSIA of saturated fatty acids in estuarine environments

2026-05-27T02:51:48+00:00

Dear ISOGEOCHEM community,
Apologies for reaching out with another question, but I would greatly appreciate your collective insights on a sampling dilemma.
I am currently planning a sampling campaign in an estuarine area to collect Suspended Particulate Matter (SPM) for compound-specific isotope analysis (CSIA) of saturated fatty acids (C16:0 to C28:0).
In much of the literature I’ve reviewed, the standard approach often involves filtering large volumes of water (100�C900 L) using 150 mm GF/F filters (Terrestrial Biomolecular Burial Efficiencies on Continental Margins, https://doi.org/10.1029/2019JG005520), and then taking a subsample (e.g., ~5g, similar to sediment samples) for lipid extraction. Due to strict [...]

Re: Thermo EA-Isolink 'not ready' issue

2026-05-26T20:42:16-04:00

Hi Susie,

I had this happen recently to two different Thermo flash EA-IRMSs. Funny timing. One had an issue reaching the reference flow setting of 70ml/min. It would get stuck around 65 or so. Changed the setting to 60 ml/min and the "not ready" went away. The other had an HTC reactor temp issue where it would fluctuate very minorly, so much so that if you weren't staring at it for 10 minutes straight you wouldn't notice. Turned that reactor off and the "not ready" issue went away. Not exactly a fix... more like a band-aid. [...]

Re: Thermo EA-Isolink 'not ready' issue

2026-05-26T23:02:48+00:00

Unclassified / Non classifié

Hi Susie,

I had similar trouble with the EFC-t module on our Thermo Flash 2000 ten years ago. I was told I would have to order a complete module, which I did (cost was over 3600 CAD at the time). It was going to take weeks to arrive, so I opened it up, found a part number on the little plastic flow sensors, and ordered two of them online from Mouser Electronics (171 CAD each). They arrived right away and swapping one of the sensors fixed the problem. I haven't had any problems with the EFC [...]

Thermo EA-Isolink 'not ready' issue

2026-05-26T15:47:23-04:00

One morning last week when I started running our EA-irMS (Thermo Flash EA Isolink-Conflo IV-Delta V Plus), the CO2 peak was about 40 seconds late on the first two standards. On subsequent standards it started giving me “waiting for EA” delays. I was able to force it to go to “ready” a few times by adjusting the reactor temps or He pressure or power cycling the EA, but it never worked properly, and it may just be coincidence that it recovered while I was twiddling knobs. After the first few attempts it never went back to “ready.” Restarting the computer [...]

Re: Low d18O carbonate standard

2026-05-26T05:39:42+10:00

Not in the range, but close:

https://analytical-reference-materials.iaea.org/iaea-co-8-2

Matheus C. Carvalho
Southern Cross University, Australia
Editor for HardwareX (Elsevier)

*Improved open source autosampler for microbalances
<https://www.researchgate.net/publication/370564297_Automated_weighing_in_the_stable_isotope_lab_when_less_is_more>*

Book: Practical Laboratory Automation Made Easy with AutoIt
<http://bit.ly/3x19AXy>

On Mon, May 25, 2026 at 9:08 PM Tim Pollard <
00001133ef6d9949-dmarc-request@list.uvm.edu> wrote:

> Hi All,
>
> I am analyzing some sub-glacial carbonates from Antarctica that have very
> low d18O values (-30 to -40 ‰, VPDB), and sit well outside the range of the
> carbonate reference materials that we normally run. I was just wondering if
> anyone is aware of a well calibrated [...]

2026 Earth Science Women's Network Leadership Roles Recruitment

2026-05-25T20:19:32+01:00

*[Deadline extended to Wednesday May 27th]*
Dear isogeochem community,

*Earth Science Women's Network (ESWN) Leadership & Volunteer Recruitment
2026*
ESWN is thrilled to announce that we are recruiting for the newest leaders
of our organization.

*ESWN Associate Board of Directors*
ESWN’s Associate Board of Directors is composed of co-chairs of four
committees that are critical to the success of our organization. For
positions starting July 1, 2026 we are accepting applications through May
27, 2026 for: [...]

Re: Low d18O carbonate standard

2026-05-25T09:12:08-05:00

Hi Tim,

You may get from IAEA the standard Light Antarctic Precipitation (SLAP) with d18O -55.5 and d2H -428.0.

Cheers,

Marcos

> On May 25, 2026, at 12:53 AM, Tim Pollard <00001133ef6d9949-dmarc-request@list.uvm.edu> wrote:
>
> Hi All,
>
> I am analyzing some sub-glacial carbonates from Antarctica that have very low d18O values (-30 to -40 ‰, VPDB), and sit well outside the range of the carbonate reference materials that we normally run. I was just wondering if anyone is aware of a well calibrated carbonate standard that has a similarly low d18O?
>
> Cheers,
> Tim

PVC samples on EA/IRMS

2026-05-25T11:02:00+03:00

Hi ISOGEOCHEM,

We have a researcher who asked us if we can determine 13C in a small number
(3) of polyvinylchloride (PVC) samples by EA/IRMS. Does one of you
have experience with running such high chlorine samples? Can we do this
without destroying our instruments, do we need to take any special
precautions?

thanks
Lukas

Low d18O carbonate standard

2026-05-25T01:53:47-04:00

Hi All,

I am analyzing some sub-glacial carbonates from Antarctica that have very low d18O values (-30 to -40 ‰, VPDB), and sit well outside the range of the carbonate reference materials that we normally run. I was just wondering if anyone is aware of a well calibrated carbonate standard that has a similarly low d18O? [...]

Re: Nuclide mass spectrometers

2026-05-24T03:46:37+00:00

Hah! Hey Michael, I learned on that same Lamont Nuclide in 1978. Same mercury columns, same Toeppler pumps, same glass flight tube, same paper strip-chart recorder and ruler to draw pencil lines and "measure" ratio offsets. Great learning experience when you can see all the warts.

That was the year we managed to get the data integration on the new Micromass to work on an HP calculator (the rest was all manual of course) and I think that was pretty much the end of that particular Nuclide - Jim White may have run some things about then too. He and [...]

Re: Nuclide mass spectrometers

2026-05-24T00:34:11+00:00

I too started out on a Nuclide. In the summer of 1964, as an undergraduate, I participated in a program at Lamont to introduce potential grad students to geochemistry. I worked with Bill Sackett, analyzing a suite of POC samples, taken across the Southern Ocean, to search for a temperature dependence of discrimination. My experience was similar to that described by other people in this thread: Toeppler pumps for combusting CO2, mercury pistons for balancing sample and reference pressures, manual switching of sample and reference, calculating pCO2 by drawing lines on graph paper… [...]

Re: Nuclide mass spectrometers

2026-05-23T22:12:43+00:00

All:

Yes, this brings back memories of challenging times. Tad Oba and Nobu Niitsuma, visiting scientists at USC, modified our Nuclide 6-60, epoxying the capillary into the glass piston so we could bring the mercury column up to a very small volume, allowing me to analyze very small samples (even single deep-sea benthic forams) in the late 1970s. It also meant that I could not go anywhere else to run my samples and had to keep the instrument running. Larry Miller and I did automate the instrument so that we did not have to manually switch the changeover valves every [...]

Re: AW: [ISOGEOCHEM] DeltaV/Isodat communication with external valves

2026-05-22T15:23:58-05:00

Just a quick follow up to say that you both were correct. I hooked up the
relay today and it worked perfectly.

Thanks!

On Thu, May 21, 2026 at 11:14 AM Jason Visser <jasonvisser@gmail.com> wrote:

> Thanks for the quick replies, Rob and Florian!
>
> I'll give it a go tomorrow. The relay just arrived, but I won't have time
> to test it until then.
>
> I'll let y'all know how it goes.
>
> Best,
> Jason
>
> On Thu, May 21, 2026 at 6:06 AM Rubach, Florian <
> 00000d9fb66b1fb2-dmarc-request@list.uvm.edu> wrote:
>
>> Hey Jason,
>>
[...]

Opening: Manager of the Ján Veizer Stable Isotope Laboratory (permanent)

2026-05-21T12:47:18-04:00

Seems the link I sent before was for internal staff - argh. Here is the
external link to the job posting:

https://uottawa.wd3.myworkdayjobs.com/en-US/uOttawa_External_Career_Site/job/Ottawa-ON/Manager--Isotope-Laboratory_JR34696

Len

Re: AW: [ISOGEOCHEM] DeltaV/Isodat communication with external valves

2026-05-21T11:14:46-05:00

Thanks for the quick replies, Rob and Florian!

I'll give it a go tomorrow. The relay just arrived, but I won't have time
to test it until then.

I'll let y'all know how it goes.

Best,
Jason

On Thu, May 21, 2026 at 6:06 AM Rubach, Florian <
00000d9fb66b1fb2-dmarc-request@list.uvm.edu> wrote:

> Hey Jason,
>
> could it be that the voltage is essentially floating until you load the
> pin, i.e. the voltage tries to actuate the relay?
>
> Florian
>
> Dr. Florian Rubach
> Abteilung Klimageochemie
> Max-Planck-Institut für Chemie
>
> Hahn-Meitner-Weg 1
> 55128 Mainz
> [...]

Opening: Manager of the Ján Veizer Stable Isotope Laboratory (permanent)

2026-05-21T08:32:36-04:00

Dear Colleagues

We are seeking a full-time permanent Manager for the Ján Veizer Stable
Isotope Laboratory in the Department of Earth and Environmental Sciences at
the University of Ottawa. This lab supports a broad range of environmental,
hydrological, ecological and geochemical isotope applications and operates
multiple Thermo IRMS platforms (Delta V+ / Delta Q), GasBench, EA-IRMS,
GC-C-pyr, TOC and Picarro and LGR aser isotope systems within a larger
national geochemistry and AMS research facility. [...]

Re: Vial cap material suitable for long-term CaCO3 storage ?

2026-05-21T11:23:06+00:00

Hello Mathieu,
I favor sealing samples in pre-annealed glass ampoules for exclusion of all and any chemical agents during long-term storage. I place a small cap of pre-annealed aluminum foil on top of the filled ampoule, pierce the cap with a syringe needle, feed dry argon through the needle into the headspace above the sample for exclusion of air, remove the needle, and immediately seal the neck of the ampoule just below the aluminum cap with the flame of a small glass blowing torch.
Cheers,
Arndt Schimmelmann

AW: [ISOGEOCHEM] DeltaV/Isodat communication with external valves

2026-05-21T06:34:09+00:00

Hey Jason,

could it be that the voltage is essentially floating until you load the pin, i.e. the voltage tries to actuate the relay?

Florian

Dr. Florian Rubach
Abteilung Klimageochemie
Max-Planck-Institut für Chemie

Hahn-Meitner-Weg 1
55128 Mainz
Tel: +49 6131 305 4128

-----Ursprüngliche Nachricht-----
Von: Stable Isotope Geochemistry <ISOGEOCHEM@list.uvm.edu> Im Auftrag von Jason Visser
Gesendet: Mittwoch, 20. Mai 2026 17:16
An: ISOGEOCHEM@LIST.UVM.EDU
Betreff: Re: [ISOGEOCHEM] DeltaV/Isodat communication with external valves [...]

Re: DeltaV/Isodat communication with external valves

2026-05-21T00:12:00+00:00

Hi Jason,
The apparent failure for the voltage to change at your output pins is a trap for us all. It seems that the valve control circuitry monitors the current draw and will not change state unless the relay/actuator/whatever load is physically connected. Using a voltmeter alone (with very high input resistance) will not register as a load. However your account of a small voltage change rings a bell with me.
Hoping I'm on the right track with this,
Rob [...]

Re: Vial cap material suitable for long-term CaCO3 storage ?

2026-05-21T00:00:44+00:00

Hi Mathieu,
I favour butyl rubber over any silicone or Teflon-based polymers for it's having the lowest gas solubilities and so presumably lowest permeabilities. Silicones in particular have high perfusivity and gas solubility ( used for membrane-inlet MS after all ).
If concerned about volatiles in your septum perhaps treatment in a vacuum oven would obviate that concern - as used to clean GC septa.
I had quite a hunt to find crimp seals of butyl rubber for 2 ml GC vials, but di get them in the end.
All the best
Rob [...]

Vial cap material suitable for long-term CaCO3 storage ?

2026-05-20T17:32:52+02:00

Hi all,

Tapping into the collective wisdom:

What screw-on cap material would you recommend for a borosilicate glass vial intended to store calcium carbonate reference materials over a decade or longer? The usual suspects seem to be PP, PTFE, and silicon seals. I'm mostly worried about the cap material degassing volatile species that may react with CaCO3 (unlikely?) and/or interfere with high-precision IRMS [1]. Each vial will be vacuum-sealed in plastic, so water permeability of the cap is not a big concern, but please let me know if you have hard evidence that vacuum-seal plastics (e.g., used for preserving food) [...]

Re: DeltaV/Isodat communication with external valves

2026-05-20T11:15:31-04:00

Thanks Matheus and all others that have offered help and resources, it's greatly appreciated. AutoIt seems quite interesting and I might make use of it in the future, but for now I think I've got Isodat and our DeltaV doing what I need.

I am observing something that I'm wondering if anyone can offer some insight into: we have 2 DeltaV Plus instruments. Nearly identical setups. I've setup external valve control through the PnM interface in Configurator identically on both. If I monitor the voltage across the pins coming out of the PnM, on one IRMS it switches between 0V [...]

Re: DeltaV/Isodat communication with external valves

2026-05-20T17:59:59+10:00

Hi, I only saw this now, as my email classified this message as spam...
I believe you can use AutoIt to do what you want, if you know the commands
that you can use to control the valve using a computer. It may be easier
than doing all the research you need to do the "proper" way. Contact me off
the list and we can go from there, if you want.
Regards, [...]

Re: valco valve actuator O-ring replacement

2026-05-19T10:52:23-04:00

Awesome,
thank you so much!
Anouk

Prof. Anouk Verheyden

Senior Lecturer and Stable Isotope Laboratory Manager

Union College
Department of Geosciences
807 Union St.
Schenectady, NY 12308

Office phone: (518) 388-8754
Lab phone: (518) 388-8741

email: verheyda@union.edu
web: http://minerva.union.edu/verheyda/research.html
Lab: http://minerva.union.edu/gillikid/lab.htm

On Mon, May 18, 2026 at 5:25 PM Poláková Ljubov <ljubov.polakova@bc.cas.cz>
wrote:

> Dear Anouk,
> To lift up the GB is really the only way to remove the actuator. Moreover,
> you need another pair of hands to hold the actuator inside the GB while
> detaching it.
> During disassembly of the actuator, *follow the original position of [...]

Deadline extended 22 June: Call for abstracts in session "Forest Ecophysiology, Genetics and Molecular Biology" IECF2026 14-16th September 2026

2026-05-19T09:14:26+02:00

Dear all,

Just a reminder that you are still on time to submit your abstract to
the 5th International Electronic Conference on Forests, deadline has
been extended till 22nd June.

https://sciforum.net/event/IECF2026?section=#session4216

Best regards,

Juan Pedro Ferrio

El 14/03/2026 a las 10:20, Juan Pedro Ferrio escribió:
> Dear colleagues,
>
> Sorry for crossposting.
>
> I would like to highlight the online session "S6. Forest
> Ecophysiology, Genetics and Molecular Biology",
> within the "5th International Electronic Conference on Forests" (
> https://sciforum.net/event/IECF2026?section=#session4216 ).
>
> The conference is fully online, and is scheduled for 14th-16th
> September 2026 CEST.
[...]

Re: valco valve actuator O-ring replacement

2026-05-18T21:20:26+00:00

Dear Anouk,
To lift up the GB is really the only way to remove the actuator. Moreover, you need another pair of hands to hold the actuator inside the GB while detaching it.
During disassembly of the actuator, follow the original position of all the parts very carefully and follow the instructions. It could be sufficient. [...]

valco valve actuator O-ring replacement

2026-05-18T16:15:03-04:00

Dear isogeochem,

I need to replace the O-ring on the air actuator of the valco valve on a GB
II. From the technical notes on the vici website, it seems I need to access
three screws on the bottom part of the actuator. I don't see a way on how
to detach the actuator from the inside of the GB and the only thing I can
think of is to lift the GB and hope there is a way to detach it from the
bottom. However, before I try this, can someone confirm that I actually
have to lift up [...]

Postdoctoral Fellow @ UTSA

2026-05-15T00:42:58-04:00

We seek an enthusiastic and versatile scientist in the fields of geosciences and stable isotope geochemistry who will contribute to our growing research program focused on the detection and characterization of stable isotopes in environmental matrices, with strong familiarity in isotope ratio mass spectrometry. The successful applicant will ideally conduct research in the broad area of low-temperature stable isotope geochemistry, focusing on the occurrence, fate, and transport of organic matter and C-O-H-N-S isotopes in soils, sediments, and water systems. Knowledge and hands-on experience with advanced instrumentation, including operation and troubleshooting of the Delta Q Isotope Ratio Mass Spectrometer, are highly [...]

Re: Eurovector question

2026-05-14T16:23:00+00:00

Linda,

It sounds to me that you might have a partial blockage with a piece of particulate in one of the solenoids of the EPCs or EFM?

Good luck!

Cheers,
Simon

*****

Simon Poulson

Research Professor

Dept. Geological Sciences & Engineering MS-172

University of Nevada-Reno

1664 N. Virginia St.

Reno, NV 89557-0138 USA

(775) 784-1104

Fax: (775) 784-1833

poulson@unr.edu<mailto:poulson@unr.edu>

*****

From: Stable Isotope Geochemistry <ISOGEOCHEM@list.uvm.edu> on behalf of Linda Godfrey <00000be4a8cd5acd-dmarc-request@list.uvm.edu>
Date: Thursday, May 14, 2026 at 7:17 AM
To: ISOGEOCHEM@LIST.UVM.EDU <ISOGEOCHEM@list.uvm.edu>
Subject: Eurovector question [...]

Eurovector question

2026-05-14T13:56:26+00:00

Good morning -

I have a Eurovector which I had turned off from lack of use. I then turned it back on (not without some issue), but have found that the carrier pressure needed to get to the same, roughly 100mL/min (excuse me if I got the units wrong) carrier flow, is very much higher than it was before I turned it off. I was looking throug hte log, and it seems that there has been a gradual increase in the carrier pressure since we got the instrument back in the 2000's (it was double (100 kPa) last time it [...]

2026 Earth Science Women's Network Leadership Roles Recruitment

2026-05-14T12:59:25+01:00

Dear isogeochem community,

*Earth Science Women's Network (ESWN) Leadership & Volunteer Recruitment
2026*
ESWN is thrilled to announce that we are recruiting for the newest leaders
of our organization.

*ESWN Associate Board of Directors*
ESWN’s Associate Board of Directors is composed of co-chairs of four
committees that are critical to the success of our organization. For
positions starting July 1, 2026 we are accepting applications through May
25, 2026 for: [...]

Re: d13C in methanol, BF3 and BSTFA?

2026-05-14T11:47:52+00:00

Hi Daniel,

I have carried out corrections for this but with an alternative approach at Glasgow using GC-IRMS- it was very easy to do. Sebastian Naeher in NZ also has done it this way and suggested it to us.

To determine the contribution of 13C from the MeOH in the derivatising agents we run an alcohol standard e.g. try 10 mg/l palmitoleic acid- un-derivatised, on the GC IRMS - the chromatography is not good but its fine for this purpose ( you may need to adjust concentration, we run in splitless mode) and run a derivatised one and use these [...]

d13C in methanol, BF3 and BSTFA?

2026-05-14T12:01:59+02:00

Dear colleagues,

I need to analyze the d13C of some reactives that we used to derivatize
our fatty acids and alkanols.

The reactives are: pure methanol, Boron trifluoride in methanol(BF3) to
methylated the fatty acids and the 3 carbons of the BSTFA
(N,O)-Bis(trimethylsilyl)trifluoroacetamide) for the trimethyl silyl
alkanols.

My idea is to analyzed this in the elemental analyzer has a “solid”
sample, it is possible or there is any kind of pre-treatment to avoid
some impurities, etc. [...]

SIMSUG 2026

2026-05-14T07:17:54+00:00

Dear stable isotope user,

The 17th meeting of the Stable Isotope Mass Spectrometry Users Group (SIMSUG) will take place 15th-16th June 2026 at the School of Chemistry, University of Bristol. The meeting brings together the latest developments and applications for the use of stable isotopes across a wide range of disciplines including: archaeology, food science, geoscience, health sciences, and forensics, to name but a few. [...]

Postdoctoral Researcher Job at the Karlsruhe Institute of Technology (KIT)

2026-05-13T19:40:08+00:00

Dear Isogeochem community,

The Institute of Applied Geosciences (AGW) at the Karlsruhe Institute of Technology (KIT) is pleased to announce the following search for a postdoctoral researcher in the Chair of Geochemistry and Economic Geology.

At the Chair of Geochemistry and Economic Geology, we focus our research on hydrothermal ore deposits, geochemistry of geothermal systems, re-mining of mine waste, pollutant dynamics and liquid mining. We wish to develop strong and visible research in these fields. We offer this position in order to strengthen our research team in the fields above with an individual that already has initial PostDoc-experience. Our laboratory [...]

Re: [EXT] [ISOGEOCHEM] Regarding the Thermocouple sensor type of TC/EA Thermo scientific .

2026-05-13T16:29:19+00:00

If your TC/EA is thermo Finnigan, the Thermocouple is Thermo Fisher Scientific Bremen 1121470, and you can order through Unity Lab. Best Wishes! Xiaoyu *********************************************** Mailing Address: Xiaoyu Zhang Environmental Isotope Lab, Geosciences The University of Arizona 1040 E. Fourth Street [...]

Save the Date – Nordic Isotope Users’ Symposium (NIS) 2027

2026-05-12T17:36:06+02:00

Dear colleagues,

Please save the date for the upcoming *Nordic Isotope Users’ Symposium
(NIS) 2027*, which will take place in beautiful Copenhagen from *23–27
August 2027*.

The symposium will feature a *three-day course and two-day symposium*
covering:

-

Traditional light-element isotopes
-

Metal isotopes
-

Radiocarbon
-

Triple oxygen isotopes
-

Clumped isotopes

Applications will include:

1.

Carbon and nitrogen biogeochemical cycles in the soil–plant–atmosphere
continuum
2.

Pollution, food, and forensic applications
3. [...]

Invitation to Join InSync Working Group on Modern Water Isotope Observations in Antarctica

2026-05-12T16:17:24+02:00

Dear colleagues,

We would like to invite you to join a new Working Group within the Antarctica InSync initiative focused on modern-day stable water isotope observations in Antarctica.

This cross-theme working group will be affiliated with Themes II, VI, VII and more, depending on the members. The working group aims to address the need for a coordinated observational network necessary to trace the origins and transport pathways of moisture reaching both the Antarctic coast and the interior. Stable water isotope measurements provide a powerful tracer of diabatic processes, enabling links between key local physical processes and the large-scale atmospheric circulation. [...]

Re: Regarding the Thermocouple sensor type of TC/EA Thermo scientific .

2026-05-12T05:42:57+00:00

Thanks for sharing this valuable information....

Regards

SIVESH AHIRWAR

Get Outlook for Android<https://aka.ms/AAb9ysg>

Small Sample Introduction Module 2 (Picarro) for sale

2026-05-11T20:30:04+00:00

HI All

I have a gently used A0314 Small Sample Introduction Module 2 available for sale.

The module should be compatible with Picarro iCO2, iCH4 (G2101-i, G2121-i, G2131-i, G2132-i, G2201-i), and select iN2O instruments (G5101-i and the G5131-i), and two concentration analyzers (G2308, G2508).

If you are interested - please contact me via email (off list) at: [...]

Re: Regarding the Thermocouple sensor type of TC/EA Thermo scientific .

2026-05-11T10:06:02-07:00

Hello Sivesh,

The table linked below shows it to be either type R or S (but with no
further info to discern between the two.) I suspect that either will
work for most applications.

https://pages.uoregon.edu/palandri/EP/Thermocouple_color_code.png

Cheers,
-Jim

On 5/11/26 05:48, Sivesh Ahirwar wrote:
> Thanks for responding me. . . I checked in TC/EA and found two wire one
> is white and 2nd is orange colour. Can you define what type this is. . .
> Thanks. Regards. . . SIVESH AHIRWAR Get Outlook for Android From:
> Srikanth Gedela <srikanth. gedela@ GMAIL. COM>
> ZjQcmQRYFpfptBannerStart
> This message originated outside the UO email ecosystem.
> Use caution [...]

Looking for a Picarro A0325 autosampler

2026-05-11T12:36:14-04:00

Hello all,
We are in search of a used Picarro A0325 autosampler. We have an older
L2140 water analyzer in need of an autosampler, it's not compatible with
the model Picarro currently sells and would need a trip back to the factory
to replace the motherboard. We're hoping to skip that step if someone has
an old A0325 we could purchase. We have a vaporizer and just need the
autosampler itself. [...]

Pyro cube

2026-05-11T13:19:50+00:00

Dear isogeochem community,
Thanks everyone with the help of pyrocube method on precisION works now like a dream!

Major issues where bake out of the CO2 trap and modifying the method that CO2 would release right at the right time.

As I have 4 interfaces on the precisION I was trying to now link the pyrocube to my older Delta V instrument via conflow 3.
Managed with help from SUERC to create a remote trigger from conflow to pyro installed the pyro software on a new computer and plugged in the USB connection directly into this computer to connect to [...]

Re: Regarding the Thermocouple sensor type of TC/EA Thermo scientific .

2026-05-11T12:48:31+00:00

Thanks for responding me...

I checked in TC/EA and found two wire one is white and 2nd is orange colour. Can you define what type this is...

Thanks.

Regards...

SIVESH AHIRWAR

Get Outlook for Android<https://aka.ms/AAb9ysg>

Re: Regarding the Thermocouple sensor type of TC/EA Thermo scientific .

2026-05-11T08:37:09-04:00

Hello Sivesha,

The color of the thermocouple lead wires, will tell the type of thermocouple
example if wire lead colors are White (+) and Red (-) its J type thermocouple, Yellow (+) and Red (-) its K type thermocouple.

Best
srikanth
srikanth_gedela@brown.edu

Regarding the Thermocouple sensor type of TC/EA Thermo scientific .

2026-05-11T10:06:29+00:00

Dear all!

I would like to ask which type of thermocouple is used in the heater of the TC EA. Our thermocouple has broken, so please let me know the correct type used in this system. Any response would be appreciated.

Thank you.
Regards,

SIVESH AHIRWAR
INDIAN INSTITUTE OF SCIENCE BANGALORE

Get Outlook for Android<https://aka.ms/AAb9ysg>

Sulfur blank and peak tailing

2026-05-07T03:39:07-04:00

Hello All,

We are experiencing a persistent sulphur blank issue with our vario ISOTOPE select configured in CNS mode. The sulphur blank is consistently around 1–2 nA peak height and could not be eliminated despite multiple blank runs and extensive troubleshooting efforts.

The following actions were already performed:

1. Installed new combustion and reduction tubes with fresh fillings
2. Cleaned the ash finger, quartz bridge thoroughly
3. Refilled the drying agent with fresh material
4. Performed multiple bake-outs of the TPD column
5. Tested with a different helium cylinder/batch
6. Replaced the TPD column with a brand-new column supplied by [...]

DeltaV/Isodat communication with external valves

2026-05-06T15:51:38-04:00

Hi all,

Hope everyone is having a great week. I'm once again looking to the experienced and knowledgeable isotope community for help.

We're looking to implement control of a 2 position vici valve with their DVI (digital valve interface, see: https://www.vici.com/support/tn/tn411.pdf), ideally within isodat as a peripheral so we can use the time event list in our method to control the valve. The DeltaV manual is very light on the details concerning the "Plug and Measure" interface. We actually have at least one spare Plug and Measure adapter, but it's not clear to me how to configure it to have [...]

Second Annual International Orbitrap-IRMS Users Meeting

2026-05-06T18:19:48+00:00

Second Annual International Orbitrap-IRMS Users Meeting, 11–12 July 2026, Montréal, Canada
The use of Orbitrap-based mass spectrometry for stable isotope analysis ('Orbitrap-IRMS') has grown significantly over the past ~10 years, and we expect that it will only continue to grow. Following upon the success of our inaugural meeting at Goldschmidt 2025, our second meeting at Goldschmidt 2026 aims to continue the development of a more formal Community of Practice among Orbitrap-IRMS users (and those interested in adopting the technology). We thus seek participation from individuals at all career stages and particularly encourage early- and mid-career scientists to attend. [...]

Re: Heated Soil Samples

2026-05-06T10:17:29+10:00

Hi Jon,
a team from Lublin just published a study on pretreatment, incl. heating,
prior to CN isotope analysis.
Samples were sludge from WWTP's, so higher in organics than soil.
They found oven drying does affect isotopes, N more than C, but
interestingly the actual T did not so much.
T tested were in between 30-105C, not as high as 125.
Journal of Environmental Chemical Engineering 14 (2026) 121927 [...]

Heated Soil Samples

2026-05-05T23:15:35+00:00

Dear Community,

An associate asked me this question: "I have a client that brought soils in from overseas and had to heat them to ~125 degrees C to get them through U.S. Customs. We're wondering if that heating could have a negative effect on the isotopic compositions for either nitrogen or carbon". My gut feel is "yes" due to the demise of any bugs or decomposing aromatics in the soil matrix, but I'm not sure and couldn't find anything obvious in the literature. So I thought I would reach out and ask your opinion. Please provide literature citations if available. [...]

Postdoctoral / senior RA position in marine ecology / geochemistry at The University of Hong Kong

2026-05-05T11:25:27+08:00

Hello All,

Please circulate the following postdoctoral opportunity to any potential
candidates. Candidates can reach out to me directly at my university (
jcyb@hku.hk) or Gmail (cybulski.j@gmail.com) with any questions.

Application reviews will start ASAP and continue until June 30, or until
the post is filled.
https://jobs.hku.hk/en/job/536137/postdoctoral-fellow-pdf-senior-research-assistant-sra

Thanks!

Jon Cybulski

*---- *

*Post-doctoral Fellow (PDF) / Senior Research Assistant (SRA) in the Swire
Institute of Marine Science (SWIMS)* [...]

Fw: Pennsylvania Geological Survey - Critical Minerals Technician position

2026-05-04T19:13:43+00:00

Dear colleagues,
Please share this opportunity with interested students, alumni, and early-career geoscientists.

Re: Troubleshooting poor response and unstable δ15N values for Lysine(NPIP)

2026-05-02T06:39:48-10:00

Have you tried inlet maintenance and trimming/baking the column? I’ve found that lysine is the canary in the coal mine for a dirty inlet. Natalie

> On May 2, 2026, at 01:27, Chen Hongguang <yc47412@connect.um.edu.mo> wrote:
>
>
> Dear all,
> Sorry to bother again. I am currently working on measuring compound-specific δ15N values of amino acids (CSIA-AA) using GC-C-IRMS, but I have encountered a persistent issue with Lysine.
> Specifically, the response for Lysine is very poor. The signal intensity (m/z=28) is only around 0.100V, whereas other amino acids in the same run show much stronger responses [...]

Troubleshooting poor response and unstable δ15N values for Lysine(NPIP)

2026-05-02T04:58:04+00:00

Dear all,
Sorry to bother again. I am currently working on measuring compound-specific δ15N values of amino acids (CSIA-AA) using GC-C-IRMS, but I have encountered a persistent issue with Lysine.
Specifically, the response for Lysine is very poor. The signal intensity (m/z=28) is only around 0.100V, whereas other amino acids in the same run show much stronger responses (around 0.400V). Furthermore, the δ15N values for Lysine are highly unstable and deviate significantly from the bulk EA-IRMS values (a difference of approximately 5‰). In contrast, the other amino acids show stable δ15N values that align well with their corresponding EA values.
[...]

Troubleshooting poor response and unstable δ15N values for Lysine (NPIP)

2026-05-01T23:50:56-04:00

Hello everyone,

Sorry to bother you. I am currently working on measuring compound-specific δ15N values of amino acids (CSIA-AA) using GC-C-IRMS, but I have encountered a persistent issue with Lysine.

Specifically, the response for Lysine is very poor. The signal intensity (m/z=28) is only around 0.100V, whereas other amino acids in the same run show much stronger responses (around 0.400V). Furthermore, the δ15N values for Lysine are highly unstable and deviate significantly from the bulk EA-IRMS values (a difference of approximately 5‰). In contrast, the other amino acids show stable δ15N values that align well with their corresponding EA values. [...]

Re: ASITA 2026 — Registration Open

2026-05-02T00:13:12+00:00

🌟 Register Now for ASITA 2026! 🌟
Advances in Stable Isotope Techniques and Applications

Join colleagues from across the stable isotope community for an engaging, hands‑on conference focused on innovation, collaboration, and practical solutions.

Why Attend ASITA?

✅ Network with laboratories, vendors, and sponsors
✅ Showcase research using novel applications and innovative techniques
✅ Share ideas, troubleshoot challenges, and learn best practices
✅ Ideal for new users, students, and technicians as well as experienced researchers
✅ Highly rated by past participants as incredibly useful [...]

Postdoctoral Position in the Noble Gas Lab at Syracuse University (Syracuse, New York)

2026-05-01T16:02:50+00:00

Hi Everyone,

My name is Khi Atchinson and I am a PhD graduate student at Syracuse University (New York, USA) that focuses on noble gas geochemistry. We are currently offering an immediately available research position in our noble gas lab that requires a PhD. This position also comes with opportunities for interdisciplinary research! [...]

Recent graduate needed by the Reston Stable Isotope Laboratory of the USGS

2026-04-30T21:45:41+00:00

The U.S. Geological Survey is seeking a recent graduate to work in the Reston Stable Isotope Laboratory. The application period closes May 19, 2026. An applicant should have experience in a stable isotope laboratory preparing and analyzing hydrogen-, carbon-, nitrogen-, oxygen-, or sulfur-bearing materials. An applicant should have an MA or MS degree awarded between July 2024 and June 2026 OR BA or BS degree awarded between July 2024 and June 2026 plus one year of experience. U.S. citizenship is required. Application instructions are found here<https://water.usgs.gov/water-resources/rsil/2026-RSIL-Advertisement.pdf>. [...]

Surplus SEM

2026-04-30T19:48:34+00:00

Hello folks,

Not sure if anyone is interested by we have an old TESCAN SEM that we are surplussing. It holds a vacuum, but there’s a high voltage problem (likely fixable). We bought a new SEM to replace it, and the space needs to be cleared in the next month or two at the latest. Anyone looking for spare parts or to fix it, please contact me. We will eventually post this to the university’s surplus system for bidding, but it will not likely go for much. It is also possible a separate agreement can be made between universities. [...]

Re: Nuclide mass spectrometers

2026-04-30T19:03:31+00:00

Daniel,

I, too, “cut my teeth” using Nuclide mass spectrometers while a graduate student at the Pennsylvania State University in the late 1970s under the guidance of Professors Peter Deines and Hiroshi Ohmoto. It was incredibly exciting to be on the forefront of research into the genesis of hydrothermal mineral deposits using a wide variety of geochemical techniques, along with several dozen stellar fellow graduate students. These techniques were all designed to liberate gases from ore and gangue minerals that could then be analyzed by the mass spectrometers. Whether roasting powdered minerals with various reagents, fluorinating other powdered minerals with [...]

Re: Nuclide mass spectrometers

2026-04-30T16:36:01+00:00

You brought back memories!

A “Micromass Optima IRMS” and an extraction line with “Uranium furnace and Toepler pump” and practising glass blowing - This is how I got introduced to the stable isotope world as a graduate student in early 90s. I spent almost 7 years in front of those.

Madhav Machavaram
Senior Research Analyst
Pegasus Technical Services, Inc.
On-Site Contractor to U.S. EPA
Center Hill Research Facility (CHRF)
5995 Center Hill Ave.
Cincinnati, OH 45224.
Phone: (513) 569 7515
Machavaram.madhav@epa.gov<mailto:Machavaram.madhav@epa.gov> [...]

Re: Nuclide mass spectrometers

2026-04-29T20:56:06+00:00

That group also analyzed some of the first lunar samples returned from the Apollo 11 mission in 1969 on that instrument…work which is still cited to this day.

Sent from Yahoo Mail for iPhone

On Wednesday, April 29, 2026, 3:43 PM, Ying Lin <ylisotope@GMAIL.COM> wrote:

Dear Daniel Snow,
These are nice things about time. I looked up, my advisor Bob Clayton and his assistant Toshiko Mayeda used a 60degree, 15cm, double collecting mass spectrometer for decades of meteorite oxygen isotope analysis. So it’s also a 6-60-RMS. It was probably custom made at the machine shop. When I joined the lab [...]

Re: Nuclide mass spectrometers

2026-04-29T12:24:28-07:00

Dear Daniel Snow,

These are nice things about time. I looked up, my advisor Bob Clayton and
his assistant Toshiko Mayeda used a 60degree, 15cm, double collecting mass
spectrometer for decades of meteorite oxygen isotope analysis. So it’s also
a 6-60-RMS. It was probably custom made at the machine shop. When I joined
the lab and I was going to learn the analysis with it, the large mercury
pump went broken. My later O2 collection after water fluorination used the
Toepler pump and the reaction line used a mercury diffusion pump. [...]

Postdoctoral position available: CSIA at U. Miami

2026-04-29T17:52:54+00:00

Dear colleagues, please circulate the following postdoctoral opportunity to potential applicants:

Postdoctoral Position in Marine Organic and Isotope Geochemistry, University of Miami

A postdoctoral position is available in the Close Lab for Marine Organic and Isotope Geochemistry<https://closelab.earth.miami.edu/>, part of the Rosenstiel School of Marine, Atmospheric, and Earth Science at University of Miami in Miami, Florida. The position is available for a start date between July 1, 2026 and September 1, 2026, although excellent candidates may be considered for earlier or later start dates. Consideration of applicants will begin immediately and close on June 1, 2026. [...]

Re: Nuclide mass spectrometers

2026-04-29T09:24:57-05:00

Hi Daniel,

With a *bit* less experience on the topic, I can say I wholeheartedly agree
with you. A feat I find spectacular is that even in the world of high
resolution time of flights and orbitraps and wacky hybrid
science-fiction-seeming-instruments, the tried and true magnetic sector
still has a meaningful use for IRMS and ICP-MS (and others still!)
functions that do not appear will be readily supplanted by those recent
developments. Of course, I take a slightly younger view of the topic: I
fondly think of the "relatively simple" quadrupole mass filter in a similar
light. Of course, there [...]