2,4-D butyl ester LC/MS/MS

[chloesabrina]

Has anyone had any luck analyzing this compound via LC/MS/MS without hydrolyzing? I am using a Waters Acquity, C18 column, and mostly organic gradient 70% to start. I am unable to see the m/z at the MW upon infusing.

[MMJ88]

Haven't done the butyl ester, but I have done 2,4-D, 2,4-DP, and 2,4-DB with a C18 column. 0.05% acetic acid and methanol, ramp from 15% organic to 95% organic.

As you already know though, the ESI ionization is going to be quite different for an ester vs. a carboxylic acid. How did you do your infusion? What concentration, what solvent, did you try both positive and negative mode, etc?

[James_Ball]

I did 2,4-D before using C18 with 0.1% Formic acid/Acetonitrile and it worked well using negative ESI. Not sure how the ester would do though.

[chloesabrina]

I used a syringe at 50 uL/min. I tried infusing a few different formulations – 100 ppb in methanol, 10 ppb in water, and 1 pmm in water. I tried both positive and negative modes.

Thanks,

[James_Ball]

I used a syringe at 50 uL/min. I tried infusing a few different formulations – 100 ppb in methanol, 10 ppb in water, and 1 pmm in water. I tried both positive and negative modes.

Thanks,

You will probably want to infuse in the solvent mixture that is equal to the mobile phase. If you start at 70% organic I would use that during they infusion. What modifiers are you using? You will need something like Formic or Acetic acid so you can generate ions.

[richiekichi]

Infusing directly into your MS for tuning? You'll probably want to use a higher concentration. 5 ppm perhaps 10 ppm. What system are you using?

[MMJ88]

I usually infuse in 50% organic with the analyte at 10ppm. Give that a try with 0.05% or 0.1% acetic or formic acid and see what you get.