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Why should we remove mobile phase before it enters MS unit in...
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Leon Drennan
Why should we remove mobile phase before it enters MS unit in...
For HPLC applications, the liquid must be removed from the sample before the MS detector can be used (in GC/MS there is no liquid to start with, just gas so no need for this step). HPLC analysis requires that we infuse solutions (i.e. mobile phase liquids) directly into an evaporation chamber of an LC-MS system. We do not infuse liquid directly into a MS source (that would be very bad!). Heated gas sources and atomization of the liquid are all used together to desolvate the liquid away and just leave the clean dry gas with the ionized particles (samples). Mass can only be measured when the molecule is converted to an electrically charged gas-phase ion. MS analysis is effected by the chemistry of the mobile phase (might be polar or non-polar) and the sample type(s). * For more information, please do a keyword search on the web for an explanation of LC-MS and MS analysis OR read an intro article or two on the same subject. *One of the best ways for you to learn is to spend time researching the answers to such basic questions on your own (yourself). Reading about the technique will teach you far more than having others provide just the answers for you.
For HPLC applications, the liquid must be removed from the sample before the MS detector can be used (in GC/MS there is no liquid to start with, just gas so no need for this step). HPLC analysis requires that we infuse solutions (i.e. mobile phase liquids) directly into an evaporation chamber of an LC-MS system. We do not infuse liquid directly into a MS source (that would be very bad!). Heated gas sources and atomization of the liquid are all used together to desolvate the liquid away and just leave the clean dry gas with the ionized particles (samples). Mass can only be measured when the molecule is converted to an electrically charged gas-phase ion. MS analysis is effected by the chemistry of the mobile phase (might be polar or non-polar) and the sample type(s). * For more information, please do a keyword search on the web for an explanation of LC-MS and MS analysis OR read an intro article or two on the same subject. *One of the best ways for you to learn is to spend time researching the answers to such basic questions on your own (yourself). Reading about the technique will teach you far more than having others provide just the answers for you.
@Hiten Shah You are right but the analyte is also a liquid but taken in small amounts. It is ionised before entering the quadrupole analyser. In the same way why can't we ionise the mobile phase. If we can't ionise the mobile phase why so? We use nitrogen as carrier gas in GC. Can we allow that to MS unit?
@Hiten Shah You are right but the analyte is also a liquid but taken in small amounts. It is ionised before entering the quadrupole analyser. In the same way why can't we ionise the mobile phase. If we can't ionise the mobile phase why so? We use nitrogen as carrier gas in GC. Can we allow that to MS unit?
I am pretty certain that you need to go read some basic texts on electrospray ionization. You DO ionize the solvent; this is why you are limited as to buffer types and solvents in LC-ESI-MS. There are many, many texts available to help you understand basic ESI, which you pretty clearly do not understand. A simple Internet search will turn up dozens for you to read. Nitrogen is very, very tricky as a carrier gas if you are using it for capillary chromatography. If you are using N2 as the carrier for packed column then you need to use a jet separator or something similar for your MS interface. Of course, if you are using packed column technology you really don't need MS and certainly can't take advantage of all that MS has to offer.
I am pretty certain that you need to go read some basic texts on electrospray ionization. You DO ionize the solvent; this is why you are limited as to buffer types and solvents in LC-ESI-MS. There are many, many texts available to help you understand basic ESI, which you pretty clearly do not understand. A simple Internet search will turn up dozens for you to read. Nitrogen is very, very tricky as a carrier gas if you are using it for capillary chromatography. If you are using N2 as the carrier for packed column then you need to use a jet separator or something similar for your MS interface. Of course, if you are using packed column technology you really don't need MS and certainly can't take advantage of all that MS has to offer.
For HPLC applications, the liquid must be removed from the sample before the MS detector can be used (in GC/MS there is no liquid to start with, just gas so no need for this step). HPLC analysis requires that we infuse solutions (i.e. mobile phase liquids) directly into an evaporation chamber of an LC-MS system. We do not infuse liquid directly into a MS source (that would be very bad!). Heated gas sources and atomization of the liquid are all used together to desolvate the liquid away and just leave the clean dry gas with the ionized particles (samples). Mass can only be measured when the molecule is converted to an electrically charged gas-phase ion. MS analysis is effected by the chemistry of the mobile phase (might be polar or non-polar) and the sample type(s).
* For more information, please do a keyword search on the web for an explanation of LC-MS and MS analysis OR read an intro article or two on the same subject. *One of the best ways for you to learn is to spend time researching the answers to such basic questions on your own (yourself). Reading about the technique will teach you far more than having others provide just the answers for you.
For HPLC applications, the liquid must be removed from the sample before the MS detector can be used (in GC/MS there is no liquid to start with, just gas so no need for this step). HPLC analysis requires that we infuse solutions (i.e. mobile phase liquids) directly into an evaporation chamber of an LC-MS system. We do not infuse liquid directly into a MS source (that would be very bad!). Heated gas sources and atomization of the liquid are all used together to desolvate the liquid away and just leave the clean dry gas with the ionized particles (samples). Mass can only be measured when the molecule is converted to an electrically charged gas-phase ion. MS analysis is effected by the chemistry of the mobile phase (might be polar or non-polar) and the sample type(s).
* For more information, please do a keyword search on the web for an explanation of LC-MS and MS analysis OR read an intro article or two on the same subject. *One of the best ways for you to learn is to spend time researching the answers to such basic questions on your own (yourself). Reading about the technique will teach you far more than having others provide just the answers for you.
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@Hiten Shah You are right but the analyte is also a liquid but taken in small amounts. It is ionised before entering the quadrupole analyser. In the same way why can't we ionise the mobile phase. If we can't ionise the mobile phase why so?
We use nitrogen as carrier gas in GC. Can we allow that to MS unit?
@Hiten Shah You are right but the analyte is also a liquid but taken in small amounts. It is ionised before entering the quadrupole analyser. In the same way why can't we ionise the mobile phase. If we can't ionise the mobile phase why so?
We use nitrogen as carrier gas in GC. Can we allow that to MS unit?
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I am pretty certain that you need to go read some basic texts on electrospray ionization. You DO ionize the solvent; this is why you are limited as to buffer types and solvents in LC-ESI-MS. There are many, many texts available to help you understand basic ESI, which you pretty clearly do not understand. A simple Internet search will turn up dozens for you to read.
Nitrogen is very, very tricky as a carrier gas if you are using it for capillary chromatography. If you are using N2 as the carrier for packed column then you need to use a jet separator or something similar for your MS interface. Of course, if you are using packed column technology you really don't need MS and certainly can't take advantage of all that MS has to offer.
I am pretty certain that you need to go read some basic texts on electrospray ionization. You DO ionize the solvent; this is why you are limited as to buffer types and solvents in LC-ESI-MS. There are many, many texts available to help you understand basic ESI, which you pretty clearly do not understand. A simple Internet search will turn up dozens for you to read.
Nitrogen is very, very tricky as a carrier gas if you are using it for capillary chromatography. If you are using N2 as the carrier for packed column then you need to use a jet separator or something similar for your MS interface. Of course, if you are using packed column technology you really don't need MS and certainly can't take advantage of all that MS has to offer.
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As MS is working in vacuum, only gas can be introduce in it and not liquid.
As MS is working in vacuum, only gas can be introduce in it and not liquid.
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