Chromatography Forum

Hi,

Every body , I got one tablet in which codeinone is present. I did LC-mass for the compound I have LCQ-Deca Quadrapole Ion trap. I used ESI probe for ionization.
The capillary temperature is 200 degree and voltage was 4.5 Kv.
I used formic acid (1% in in Acetonitrile and Water with pH 4.4) but did not got very sharp ionization is +ive mode. In fact I got comarative good TIC peak in -ive mode and got the mass just one less (i.e 295.8 the originla mass is 297).
I want to know how can I got actual mass or M+H mass and what is the mass spectrum pattern of this codeinone.
In which tablet this one is used.

Best regards

Praveen

Maybe this can help you,
http://www.sciencedirect.com/science/ar ... 0503005397

For my opinoin, oipate and it analogues (morphinans) can be ioninized with well ion ratios when use high collision energy at 30-50 eV depend on your instrument type.

Jetjamnong

I did the LC-mass analysis of codeinone. This time I used 0.1% TFA in ACN and water both and prepare the sample solution in ACN ().1% TFA) : Water(0.1% TFA) : : 50:50 ratio.
This time peak is ionized on +ive mode but the base pak was observed 152 It seems the molecule was break and 152 is stable fragment.
Now how I can conclude this 152 is related to 297 i.e mass of codeinone

Best regards

praveen

I think if you want to see the Molecular ion of your target (here is Codeinone) by using LC-MS.
If this is my case, I will have the following idea,
1. Dissolve tablet with Methanolic solvent not in Acetonitrile to provide about 1 ug/ml solution.
2. Use C18 or other LC coloumn to separate this compound.
3. Set up Mass Spectrometer for ready to run on Full Scan mode or Use MRM mode with low collision energy for getting Specific fragments pattern while the M+H is present.

Jetjamnong

Sir,

I case of ESI we are applying 200 to 320 degree C the normal temperature range.
Can we use our mass spectrometer below this range ???? If yes then what is the lower limit to ooperate the ESI mode???

For ESI temperature setting is depend on LC flowrate. If your flowrate is lower 200 ul/ml, I think you can apply the temperature in range of 150-200 °C.
For example,

Flow Rate (μl/min), 1 – 10 200 – 500
--------------------------------------------------------
Nebulizer Pressure (bar), 0.4-0.6 1.0-1.6
--------------------------------------------------------
Drying Gas Flow (l/min), 2-4 8-12
--------------------------------------------------------
Drying Gas Temp. (°C) 150-200 200-250

However, Setting up all MS parameters depend on the type of your instrument.

Jetjamnong

On a DecaXP at flow rates of 150-500uL/min I would not go lower than about 230 degrees C. If you do, drying efficiency will decline, and you will see reduced sensitivity and probably odd spikes of noise in occasional spectra. I would be very wary of going lower than 200 degrees even at low flow-rates.

I would also avoid TFA if possible as it hinders ionisation in this instrument.

What did you use to tune your instrument? Do you have a pure standard with which you could try direct infusion, to exclude issues with chromatography?

No sir,

I do not have any standard , I just received a tablet and did the mass.
Any other clues

Maybe this can help you,
http://www.sciencedirect.com/science/ar ... 0503005397

For my opinoin, oipate and it analogues (morphinans) can be ioninized with well ion ratios when use high collision energy at 30-50 eV depend on your instrument type.

Jetjamnong

Hi Jetjamnong:
Can you help me with Agilent 6340 LCMS,
702 686 7164
Bill