Hi Murali, the ESI process is, in extreme synthesis, a fast desolvatation in an high electric fields. Ionizable samples in solution can be view as ionic couples: positive-negative ions, the electric fields separates the charges while a fast evaporation is forced. In absence of salts, according to the Bronsted-Lowry theory, we can only get the formation of protonated and deprotonated species, upon the separation and volatilization only the positive ones (the protonated) are detected by the MS analyzer (or the deprotonated ones in the negative polarity). If If sodium or ammonium are present in the solution (in the buffer or in your original sample), those ions can directly charge the analytes replacing the proton to give ionic couples, then you can observe sodium or ammoniun adducts at the end of the process.
Hi Murali, the ESI process is, in extreme synthesis, a fast desolvatation in an high electric fields. Ionizable samples in solution can be view as ionic couples: positive-negative ions, the electric fields separates the charges while a fast evaporation is forced. In absence of salts, according to the Bronsted-Lowry theory, we can only get the formation of protonated and deprotonated species, upon the separation and volatilization only the positive ones (the protonated) are detected by the MS analyzer (or the deprotonated ones in the negative polarity). If If sodium or ammonium are present in the solution (in the buffer or in your original sample), those ions can directly charge the analytes replacing the proton to give ionic couples, then you can observe sodium or ammoniun adducts at the end of the process.
Giuseppe - 'EI' is 'electron ionization' , unrelated to electrospray ionization, and results in loss of one (or very occasionally more) electrons and a positive molecular ion.
Electrospray ionization forms adducts as it involves a desolvation process from a charged droplet at atmospheric pressure, resulting in either proton transfer to or subtraction from the analyte molecule, or else the addition of another cation or anion present in the droplet to the molecule.
Giuseppe - 'EI' is 'electron ionization' , unrelated to electrospray ionization, and results in loss of one (or very occasionally more) electrons and a positive molecular ion.
Electrospray ionization forms adducts as it involves a desolvation process from a charged droplet at atmospheric pressure, resulting in either proton transfer to or subtraction from the analyte molecule, or else the addition of another cation or anion present in the droplet to the molecule.
Hi Murali,
the ESI process is, in extreme synthesis, a fast desolvatation in an high electric fields. Ionizable samples in solution can be view as ionic couples: positive-negative ions, the electric fields separates the charges while a fast evaporation is forced. In absence of salts, according to the Bronsted-Lowry theory, we can only get the formation of protonated and deprotonated species, upon the separation and volatilization only the positive ones (the protonated) are detected by the MS analyzer (or the deprotonated ones in the negative polarity). If If sodium or ammonium are present in the solution (in the buffer or in your original sample), those ions can directly charge the analytes replacing the proton to give ionic couples, then you can observe sodium or ammoniun adducts at the end of the process.
Hi Murali,
the ESI process is, in extreme synthesis, a fast desolvatation in an high electric fields. Ionizable samples in solution can be view as ionic couples: positive-negative ions, the electric fields separates the charges while a fast evaporation is forced. In absence of salts, according to the Bronsted-Lowry theory, we can only get the formation of protonated and deprotonated species, upon the separation and volatilization only the positive ones (the protonated) are detected by the MS analyzer (or the deprotonated ones in the negative polarity). If If sodium or ammonium are present in the solution (in the buffer or in your original sample), those ions can directly charge the analytes replacing the proton to give ionic couples, then you can observe sodium or ammoniun adducts at the end of the process.
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Giuseppe - 'EI' is 'electron ionization' , unrelated to electrospray ionization, and results in loss of one (or very occasionally more) electrons and a positive molecular ion.
Electrospray ionization forms adducts as it involves a desolvation process from a charged droplet at atmospheric pressure, resulting in either proton transfer to or subtraction from the analyte molecule, or else the addition of another cation or anion present in the droplet to the molecule.
Giuseppe - 'EI' is 'electron ionization' , unrelated to electrospray ionization, and results in loss of one (or very occasionally more) electrons and a positive molecular ion.
Electrospray ionization forms adducts as it involves a desolvation process from a charged droplet at atmospheric pressure, resulting in either proton transfer to or subtraction from the analyte molecule, or else the addition of another cation or anion present in the droplet to the molecule.
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Do adducts form even in EI ionization? they shouldn't because the atmosferic pressure but I'm not sure.
Do adducts form even in EI ionization? they shouldn't because the atmosferic pressure but I'm not sure.
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