4-nitrophenyl 2-chloroethylcarbamate ,No signal by MS detect

[dali96]

Hello,everyone:

I detect 4-nitrophenyl 2-chloroethylcarbamate with LC-MS.but I cound not find the peak with m/z=245.what wrong with me ?

The test condition is :

Instrument: thermo LTQ-ORBITRAP, ms detection is LTQ;
Scan mode :"+"
ESI heater temp:300degree
I spray voltage: 3KV
capillary temp:300degree
scan range（m/z): 50-500

mobile phase contain : 0.1% formic acid. or 10mmol/L ammonium acetate

Sorry, I cann't paste the chemical structure in this page

thanks of all

[James_Ball]

When using the Ammonium Acetate in the Mobile Phase you may be generating the M+Ammonium adduct. Try looking for M+H+17 as the mass(m/z=262).

[dali96]

When using the Ammonium Acetate in the Mobile Phase you may be generating the M+Ammonium adduct. Try looking for M+H+17 as the mass(m/z=262).

Thanks, James_ball,I look for the peak with m/z=262，there is no.Now I am trying to find if there is some of its fragments with +Ammonium adduct.
Thank you.

[mckrause]

Are you using a column (you mention mobile phase)? If so, are you sure it is eluting? Might try running it straight into the source at relatively high concentrations to get a true spectra, at that way you know wht to look for under your conditions.

[dali96]

Are you using a column (you mention mobile phase)? If so, are you sure it is eluting? Might try running it straight into the source at relatively high concentrations to get a true spectra, at that way you know wht to look for under your conditions.

Dear sir/madam:
I detected the compound by ms and lc-ms.there are all no 245[M+H ]or 262[M+NH4].I want to know if the compound has signal in MS?

[JMB]

Suggest that you search the mass spectrum for any signal that shows the characteristic 3:1 signal for an ion that contains a single Cl atom.

This will show you whether the analyte has degraded in the source.

What was your scan range ??

[JMB]

MS/MS on the [M+H]+ ion would be expected to give, inter alia,

MH+ - HCl; m/z 209 (singlet)
MH+ - NO2; m/z 199/201 doublet

NO2C6H4O-CO+; m/z 166 (singlet)
CH2CH2Cl+; m/z 63/65 doublet.

If the molecule is unstable you might see some of these under non-CID conditions.

[JMB]

Back to basics---do you have an HPLC/UV chromatogram to show that the analyte was actually eluted from the column ??