Re: [AMMRL] 6Li preamp filter for 2H locking?

From: Akien, Geoffrey via groups.io <g.akien=lancaster.ac.uk_at_groups.io>
Date: Tue, 9 Jun 2026 14:03:56 +0000

Hi David,

We have such a system at 400 MHz (iProbe with no internal filters), and the
"complete" package is two filters for the 2H lock and X channels, respectively:

The 2H-stop filter is essential for getting anything useable out of 6Li-observe
experiments. Without the 2H-stop filter you can clearly see large artefacts
even during a wobb, and these decrease as you decrease the lock power.

I must admit I've never tried not using the 6Li-stop filter on the 2H lock,
so I can't say either way how essential that one is. What I can say is that
the sharper filter comes at a cost of ~1 dB lock power, and there is a change
in the lock phase that is just the right size that it throws off the autolocking
procedure and is better set manually the first time after adding the filter.
Other than that, it works as advertised.

Thanks

Geoff

> From: main_at_ammrl.groups.io On Behalf Of Michael Groves via groups.io
> Sent: 09 June 2026 14:29
> To: main_at_ammrl.groups.io
> Subject: [External] Re: [AMMRL] 6Li preamp filter for 2H locking?


Hi David,

I just checked and it looks like there have been some of those sold in the
past few years. There are currently none in stock so they're probably made
to order so there will be some lead time. If you email customersupport.bbio.amer_at_bruker.com
and tell them that you want to order a Z42408 they can get you a quote and
take your order.

Cheers,

Mike

On Monday, June 8, 2026 at 01:17:28 PM MDT, Anklin, Clemens via groups.io wrote:


Hi David,

you can also try turning off the lock during data acquisition. The easiest
way to do this is to use the pulsprogram zgig2h This is a sequence that is
designed to do a 1D with deuterium decoupling during acquisition. It will
lock during the relaxation delay and switch to 2H pulsing during collection
of the FID.

This effectively disconnects the lock from the probe. You can set observe to
6Li and the decoupling nucleus to 2H and set the decoupler power to 0W or
1000 db

Let me know if this helps.

Clemens

On 6/8/2026 1:41 PM, David Halat via groups.io wrote:

Hi all,

We are trying to run 6Li solution NMR on a Bruker 400 MHz system and appear
to be getting, perhaps unsurprisingly, substantial 2H lock-related noise in
our 6Li NMR spectra. The screenshot here shows experiments that are nominally
identical except that the red spectrum was run with lock on, and gave multiple
ADC overflow warnings. Running without 2H lock seems to significantly help the
noise problem (blue spectrum). However, we would like to ultimately run some
6Li experiments with 2H locking to avoid drift in longer experiments to improve SNR.

I thought that preamp filtering might help here. I see that there is a preamp
filter that Bruker provides, seen below - does anyone know how to get a hold
of a Bruker 400 MHz 6Li-pass / 2H-stop filter, or who the right contact would
be, assuming these parts are still manufactured? Or any other advice that might
help here? Thanks!

The specific part I found is Z42408, listed in Bruker manual Z31430_09
https://2210pc.chem.uic.edu/nmr/downloads/bruker/en-US/pdf/z31430_9.pdf
as Z42408 FILTER 400 6LI-PASS / 2H-STOP

Best,
David


-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#3507): https://urldefense.com/v3/__https://ammrl.groups=
.io/g/main/message/3507__;!!PvDODwlR4mBZyAb0!Rai_y0cBbQ31Qlw-wkVecll6s40OfM=
2Eq9z8iuX0YpKeD50T5xhvHD3bsJuRxMRviGulRt1MiFbP83-C4sCFWjOmkfUC$
Mute This Topic: https://urldefense.com/v3/__https://groups.io/mt/119710188=
/7559972__;!!PvDODwlR4mBZyAb0!Rai_y0cBbQ31Qlw-wkVecll6s40OfM2Eq9z8iuX0YpKeD=
50T5xhvHD3bsJuRxMRviGulRt1MiFbP83-C4sCFWgd60d-J$
Group Owner: main+owner_at_ammrl.groups.io
-=-=-=-=-=-=-=-=-=-=-=-






Received on Tue Jun 09 2026 - 07:05:27 MST