Thanks Gerry! I will let you know how it turns out.


Kind regards,



From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of gerard olack
Sent: Monday, January 23, 2017 12:26 PM
To: [log in to unmask]
Subject: [EXTERNAL]Re: [ISOGEOCHEM] High m/z 45.0 Reading on Delta V Plus


HI Yvette--

Electronic offset, or however Isodat spells it, will adjust the values. It's one of the buttons usually above the High Voltage and Magnet readouts. Make sure you don't have any gases going into the source and that all detectors should be at 0.  And when you do/re-do the measurement, the values should be close to 0.  If not, keep an eye on it to make sure it is not drifting.  You can also do background readings at the start of a sequence line.

take care,



On 1/23/2017 10:24 AM, Glenn, Agnes Y. wrote:

Hi everyone,


We have a Delta V Plus instrument on which we analyze C13/C12 ratios.  Our current m/z readings are as follows: m/z 44.0 = 0 mv; m/z 45.0 = 10 mV and m/z 46.0 = 0 mV.  Could someone please send suggestions to help us reduce the m/z 45.0 reading back to 0 or 1 mV?





Agnes Yvette Glenn, PhD

Chemist, Beverage Alcohol Laboratory

TTB Scientific Services Division

6000 Ammendale Rd.

Beltsville, MD 20705

Phone: 240-264-1584

Fax: 202-453-2311