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4-nitrophenyl 2-chloroethylcarbamate ,No signal by MS detect
Posted: Mon Jul 01, 2013 4:05 am
by 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
Re: 4-nitrophenyl 2-chloroethylcarbamate ,No signal by MS de
Posted: Tue Jul 02, 2013 5:37 pm
by 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).
Re: 4-nitrophenyl 2-chloroethylcarbamate ,No signal by MS de
Posted: Wed Jul 03, 2013 1:09 am
by 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.
Re: 4-nitrophenyl 2-chloroethylcarbamate ,No signal by MS de
Posted: Thu Jul 04, 2013 4:16 am
by 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.
Re: 4-nitrophenyl 2-chloroethylcarbamate ,No signal by MS de
Posted: Fri Jul 12, 2013 7:29 am
by 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?
Re: 4-nitrophenyl 2-chloroethylcarbamate ,No signal by MS de
Posted: Fri Jul 12, 2013 3:35 pm
by 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 ??
Re: 4-nitrophenyl 2-chloroethylcarbamate ,No signal by MS de
Posted: Fri Jul 12, 2013 3:54 pm
by 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.
Re: 4-nitrophenyl 2-chloroethylcarbamate ,No signal by MS de
Posted: Fri Jul 12, 2013 3:58 pm
by JMB
Back to basics---do you have an HPLC/UV chromatogram to show that the analyte was actually eluted from the column ??