Comparison between a linear ion trap and a triple quadruple MS in the sensitive detection of large peptides at femtomole amounts on column

Abstract

In addition to the importance of sample preparation and extract separation, MS detection is a key factor in the sensitive quantification of large undigested peptides. In this article, a linear ion trap MS (LIT-MS) and a triple quadrupole MS (TQ-MS) have been compared in the detection of large peptides at subnanomolar concentrations. Natural brain natriuretic peptide, C-peptide, substance P and D-Junk-inhibitor peptide, a full D-amino acid therapeutic peptide, were chosen. They were detected by ESI and simultaneous MS(1) and MS(2) acquisitions. With direct peptide infusion, MS(2) spectra revealed that fragmentation was peptide dependent, milder on the LIT-MS and required high collision energies on the TQ-MS to obtain high-intensity product ions. Peptide adsorption on surfaces was overcome and peptide dilutions ranging from 0.1 to 25 nM were injected onto an ultra high-pressure LC system with a 1 mm id analytical column and coupled with the MS instruments. No difference was observed between the two instruments when recording in LC-MS(1) acquisitions. However, in LC-MS(2) acquisitions, a better sensitivity in the detection of large peptides was observed with the LIT-MS. Indeed, with the three longer peptides, the typical fragmentation in the TQ-MS resulted in a dramatic loss of sensitivity (> or = 10x).

Improved sensitivity of the nano ultra-high performance liquid chromatography-tandem mass spectrometric analysis of low-concentrated neuropeptides by reducing aspecific adsorption and optimizing the injection solvent

“…water/ACN/FA (45/50/5 V/V/V), found to be optimal for peptide dissolution, is not suitable for peptide dilution. In fact, all solvents containing ACN give rise to the lowest responses in both types of Eppendorf tubes, which is in contrast with previously reported observations [20,36]. Because of the discrepancy between our results and literature, we strongly believe that the effect of organic solvent on adsorption depends on the nature of the peptide.…”

A design of experiments concept for the minimization of nonspecific peptide adsorption in the mass spectrometric determination of substance P and related hemokinin‐1

“…As expected from the literature , regular glass vials were unsuitable for measuring SP sensitively. It is most likely that the two positive charges of arginine and lysine in the amino acid sequence of SP showed high affinity to the untreated negatively charged silanol groups of glassware, resulting in a substantial loss of predicted peak area (−71.6% compared to regular polypropylene tubes).…”

Temperature-based on-column solute focusing in capillary liquid chromatography reduces peak broadening from pre-column dispersion and volume overload when used alone or with solvent-based focusing

“…Maes et al [23] found that an acidic water/AN (87:13 v/v) solvent was best for a set of neuropeptides. Earlier, Vatansever et al noted that acidic AN/water solvents were best for a series of peptides but the optimal concentration of acetonitrile, which was as high as 30%, depended on the peptide [24]. Amyloid peptides are best handled in basic water/AN 80:20 [25,26], while calcitonin is stable in water/AN (43:57).…”