Salt Tolerance Enhancement of Liquid Chromatography-Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry Using Matrix Additive Methylenediphosphonic Acid

Abstract

Mass spectrometry (MS) is a highly sensitive analytical technique that is o en coupled with liquid chromatography (LC). However, some bu ering salts used in LC (e.g., phosphate and tris(hydroxymethyl) aminomethane (Tris)) are incompatible with MS since they cause ion-source contamination and signal suppression. In this study, we examined salt tolerance of MALDI and applied a matrix additive methylenediphosphonic acid (MDPNA) to reduce salt-induced signal suppression. MDPNA signi cantly improved the salt tolerance of MALDI-MS. Using ammonium formate bu er at pH 5.0, the e ective range of bu ering salt concentration in MALDI-MS using MDPNA was estimated up to 250 mM. MDPNA reduced signal suppression caused by bu ering salts at pH 4.0 to 8.0. We observed that MDPNA e ectively worked over a wide range of bu er conditions. MDPNA was further applied to hydrophilic interaction chromatography (HILIC) and chromatofocusing-MALDI-MS. As a result, the analytes in the eluent containing high-concentration salts were detected with high sensitivity. us, our study provides simple and fast LC-MALDI-MS analysis technique not having strict limitation of bu ering condition in LC by using matrix additive MDPNA.

Study of glycosylation of prostate-specific antigen secreted by cancer tissue-originated spheroids reveals new candidates for prostate cancer detection

“…An aliquot of the dissolved sample solution (1.0 μL) was mixed with 0.5 μL of 1% methylene-diphosphonic acid on the target plate to reduce salt-induced signal suppression 49 . After drying, the samples were mixed with 0.8 μL of 2,5-dihydroxybenzoic acid solution (5 mg/ml, Shimadzu Biotech, Kyoto).…”

Classification of <i>Cutibacterium acnes</i> at phylotype level by MALDI-MS proteotyping

“…One µL of sample/matrix mixture was spotted onto the MALDI target and dried in air. Methylenediphosphonic acid (MDPNA) 36) solution at a concentration of 1% (w/v) was prepared with 50% ACN with 1% TFA solution. The MDPNA solution was used for the preparation of a matrix solution with MDPNA.…”

Membrane Protein Analyses Using Alkylated Trihydroxyacetophenone (ATHAP) as a MALDI Matrix

“…Alternatively, the analyte solution (0.5 μL), the matrix solution (0.5 μL), and the MDPNA solution were mixed on a stainless-steel plate. MDPNA solution reportedly suppresses background peaks and improves sensitivity for crude, contaminated, or mixture analytes. , …”

“…MDPNA solution reportedly suppresses background peaks and improves sensitivity for crude, contaminated, or mixture analytes. 37,38 MALDI-MS. MALDI-TOFMS measurement was performed using an AXIMA Performance (Shimadzu/Kratos, UK) mass spectrometer equipped with a nitrogen UV laser (337 nm) in linear or reflectron positive-ion mode. Data was obtained using raster scanning with five shots of laser irradiation at each of 400 data points in square regions of 1000 μm × 1000 μm with a 53 μm measurement pitch (i.e., a 20 × 20 lattice) using ATHAP or CHCA.…”