The CNRS is holding an external recruitment competition at the LIENSs UMR7266 laboratory in La Rochelle, France. The deadline for applications is July 9, 2026.
This is competition number 85.
We are seeking a Chemical Analysis Engineer to develop methodological techniques for separating specific compounds (fatty acids, amino acids) using isotope ratio mass spectrometry by GC-c-IRMS (Compound Specific Isotope Analysis, CSIA) to determine their carbon and nitrogen isotopic composition.
I am looking for a way to efficiently grind many soil samples to the fine powder needed for combustion in an EA.
If you have a ball mill you are especially happy with or a self-engineered/machine shop crafted device that works well, I would love to hear about it.
I recall once seeing something that looked like a convenience store hot dog roller onto which were placed metal cylinders containing soil samples and stainless steel balls. When the roller turned, the cylinders rotated on it at a rate that allowed the stainless steel balls to grind the soil.
My lab routinely processes large numbers of soils for EA, and yes we do use a "weenie roaster"-style roller! Ours is ancient, but the most similar modern equivalent I see from a quick online search looks like the MRC RJM Series Lab Jar Roller Mill. Ours is much wider and accommodates ~40 small jars, but that product looks like it has optional stacked tiers to increase the smaller working area?
We use a hot dog roller type soil fine grinding system similar to what you described. We don not use stainless steel balls to grind the soil, but two cylindrical steel rods of different diamters.
I will send some pics to the email address in your signature block.
I am very pleased to announce that the 2027 IAEA Isotope Hydrology Symposium will take place 10-14 May 2027 at the Vienna International Centre, Vienna Austria.
The conference website is available at this link - International Symposium on Isotope Hydrology | IAEA<https://www.iaea.org/events/isih2027>. Key deadlines and the process for submitting an abstract and applying for grant funding are all available on this site. Note that there is no charge to attend the conference but all participant must be registered.
mid of May the ion source cable of one of our MAT253 systems (red cable feeding the source) was replaced by a new cable. This MAT253 is connected to an elemental analyzer and ConFlo system.
At the beginning I was happy, since it seemed much easier to get all the wires properly connected onto the pins / feedthroughs. We had a bit of trouble with signal stability first, but after a while everything settled.
Regarding the bulbs, there is a small red light that turns on when one of the heat bulbs in the ion source fails. You can see it through the slots of the panel that covers the electronic boards on the MAT 253 - in the upper right corner. Did you see that the light was on before replacing bulbs, and confirm that it was off after switching bulbs? And after replacing the ion source?
I hope this email finds you well. I am reaching out to share a job opportunity within our faculty in Dresden.
We are currently looking for someone to support the setup of a new noble gas mass spectrometry system. The position is a fixed-term contract for approx.16 months. We are specifically looking for someone with hands-on experience in scientific instrument building. Neither A PhD nor are German skills required - English is perfectly fine.
We have an old LGR DLT-100, which was working fine until it wasn't. We had hardware issues, and we think we solved it with board replacement (I don't know the details). However, when we wanted to start the system, it was blank, didn't boot. We want to install a new hard disk but we don't have the OS to install it. Does anyone have the resources for this OS?
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
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).
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
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
- 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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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
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.
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 <[log in to unmask]> Im Auftrag von Seth Newsome Gesendet: Dienstag, 2. Juni 2026 15:10 An: [log in to unmask] 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
- 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?
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.
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…
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.
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.
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…
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
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>*
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.
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.
If it helps to have key search, what you’re describing sounds like a type of rod mill (as opposed to a ball mill). There are many large industrial examples, but there also seems to be some lab scale models available for sample prep. Eg here: https://m.made-in-china.com/product/Laboratory-Sample-Preparation-Used-Bottle-Roller-Rod-Grinder-Ball-Mill-1905720455.html
Cheers, Steve
Sent from my iPhone
> On Jun 12, 2026, at 5:47 PM, Lazarus, Brynne E <[log in to unmask]> wrote: > > > Thank you, Jenny, > > This is exactly what I had in mind! I so appreciate you taking the time to point me in the right direction. > > Best, > Brynne
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 <[log in to unmask]> 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
