Sensitive detection of charge derivatized peptides at the attomole level using nano-LC-ESI–MRM analysis

Peptides Labeled with Pyridinium Salts for Sensitive Detection and Sequencing by Electrospray Tandem Mass Spectrometry

“…Although this method was characterized by improved sensitivity of detection, even at the attomole level17, their applicability to peptide sequencing was questionable due to the insufficient stability of linear N,N,N -trialkyl QAS, during MS/MS experiment in view of Hofmann elimination18. Due of these reasons, QAS-peptide conjugates based on rigid amines such as 1-azabicyclo[2.2.2] octane (ABCO)19 and 1,4-diazabicyclo[2.2.2]octane (DABCO)20 or 5-azaspiro[4.4]nonane21 was developed to eliminate of the quoted problem.…”

Synthesis and mass spectrometry analysis of quaternary cryptando-peptidic conjugates

“…The detection of smaller amounts (50 fmol; Figure S2c) using the standard ESI source was problematic. According to our previous study the level of detection of protonated H‐DVYT‐NH 2 peptide was described as 10 −12 mole (1 pmol) . The tenfold increase of the ionization efficiency was observed for the obtained QCP conjugates.…”

“…It was shown that the more hydrophobic analyte has a greater affinity for the surface of the droplets produced by ESI than a less hydrophobic one [17]. The previously presented by us fixed charge tags [8] containing only hydrocarbon chains may be considered as more hydrophilic that those based on cryptand molecules. Therefore, it can be concluded that the hydrophilic properties of cryptands used for peptide charge derivatization may induce lower ionization efficiency of QCP conjugates than those fixed charge tags based on the N,N,N-triethylamine or azabicyclo[2.2.2]octane (ABCO) containing hydrophobic carbohydrate chains.…”

Simple approach to derivatization of alcohols and phenols for the analysis by matrix(surface)‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

“…The conversion of peptides into such derivatives with covalently bonded charges for ESI‐MS analysis remains popular to date. Thus, recent investigations in sensitive ESI‐MS detection involved preliminary two‐stage conversion of peptides into N‐terminal ammoniumacetyl derivatives by reaction with iodoacetic acid (in the presence of dicyclohexylcarbodiimide) or iodoacetic anhydride followed by treatment with various trialkylamines . A number of special reagents have been suggested to insert similar fixed‐charge‐containing groups into N‐terminii.…”

“…Thus, recent investigations in sensitive ESI-MS detection involved preliminary two-stage conversion of peptides into N-terminal ammoniumacetyl derivatives by reaction with iodoacetic acid (in the presence of dicyclohexylcarbodiimide) or iodoacetic anhydride followed by treatment with various trialkylamines. [13,14] A number of special reagents have been suggested to insert similar fixed-charge-containing groups into N-terminii. N-Hydroxysuccinimide esters of ω-ammonium carboxylic acid [15] and (2,4,6-trimethoxyphenyl)phosphonium acetic acid (TMPP-acetic acid) [16] were successfully used to enhance the ionization efficiency of peptides and to obtain sequence information by MALDI-time-of-flight post-source decay (TOF-PSD) MS. [17] Derivatization via ammonium acylation has also been applied for the analysis of low-molecular-weight amines and alcohols by ESI-and MALDI-MS. [2,3] Another derivatization method is based on the reaction between alcohols and 2-fluoro-1-methylpyridinium tosylate which has been described by Van Berkel et al in the first paper on derivatization for ESI-MS. [18] A very interesting and promising derivatization approach to fatty and steroid alcohols for MALDI-Fourier transform (FT)MS has been reported recently.…”