Untargeted Screening of Urinary Peptides Using Offline Nano-Liquid Chromatography: MALDI-TOF/TOF Mass Spectrometry.

In renal transplantation, the discovery of early urine biomarkers of graft lesions would be useful in helping physicians to improve patient care and minimize the use of invasive techniques such as biopsies. Over the last years, high-resolution mass spectrometry has been used extensively for the search of biomarkers in various biological fluids. Here we describe a procedure based on reverse-phase nano-HPLC, offline plate spotting, and MALDI-TOF and TOF/TOF applied in our laboratory for the search of natural peptides in urine samples from renal transplant patients.

Hydrophilic interaction liquid chromatography as second dimension in multidimensional chromatography with an anionic trapping strategy: application to prostate-specific antigen quantification.

Liquid chromatography (LC) coupled with tandem mass spectrometry (MS-MS) in selected reaction monitoring mode (SRM) has become a widely used technique for the quantification of protein biomarkers in plasma and has already proven to give similar results compared to the conventional immunoassays. To improve the lack of insufficient sensitivity for quantification of low abundance protein, we propose a new two dimensional liquid chromatography (2D-LC-SRM) method for the quantitation of prostate specific antigen (PSA) in human plasma. The method centers on anion exchange cartridge between reversed-phase chromatography and hydrophilic interaction liquid chromatography (HILIC) in an on-line arrangement.