MALDI Mass Spectrometric Analysis of Nonderivatized Steroids Using Cyclodextrin-supported 2,5-Dihydroxybenzoic Acid as Matrix

Abstract

Sex hormones are important metabolites in vertebrates' development and reproduction. For rapid screening sex hormones, matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is one of the promising analytical platforms, but MALDI MS faces many challenges in detecting steroids such as low ionization efficiency and matrix background interference. One potential strategy to overcome matrix interference in the low m/z region is using a cyclodextrin (CD)-supported matrix for steroid analysis since CDsupported matrixes are known to effectively suppress matrix-related ion signals. In this study, we aimed to find the optimal CD-supported matrix for the analysis of the nonderivatized sex steroids. Our results showed that the αCD-supported 2,5-dihydroxybenzoic acid (DHB) matrix efficiently ionized all three major classes of sex hormones, estrogens, androgens, and progestagens, with low or no matrix background and also with high sensitivity. In addition, the αCD-supported DHB matrix mainly generated molecular ions or protonated ions of sex hormones, and this enabled us to obtain information-rich tandem mass spectra which potentially lead to unambiguous identification of steroid species from complex metabolite mixtures.

Highly efficient, processive and multifunctional recombinant endoglucanase RfGH5_4 from Ruminococcus flavefaciens FD-1 v3 for recycling lignocellulosic plant biomasses

“…For mass spectrometric analysis, 1 μL of hydrolysate produced was mixed with 1 μL of DHB (10 mg/mL) matrix (in 50:50%, v/v acetonitrile: water, and 0.1%, v/v trifluoroacetic acid). The analysis was performed as per the earlier reported protocol [24]. MALDI-TOF MS was performed on time-of-flight mass spectrometer Autoflexspeed (Bruker Daltonics, Bremen, Germany) in positive reflectron mode.…”

MALDI Matrices for the Analysis of Low Molecular Weight Compounds: Rational Design, Challenges and Perspectives

“…The incorporation of an SOM in the macrocyclic cavity leads to a reduced observance of SOM related fragment ions and alkali metal ion adducts. E.g., the insertion of 2,4,6‐trihydroxyacetophenone (THAP) allowed the detection of testosterone and diazepam, [48] and similarly, after incorporation of DHB in the CD cavity, a number of nonderivatized sex steroids, e. g., estrone, β‐estradiol, testosterone and progesteron were successfully analyzed [49] . Combining classic organic matrices with e. g., nanoparticles also can be described as binding them to a supplementary structure.…”

Infrared pulsed fiber laser‐produced gold and silver‐109 nanoparticles for laser desorption/ionization mass spectrometry of steroid hormones

“…Matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) is a highly sensitive and accurate method used nowadays. However, MALDI‐MS of neutral steroid hormones is difficult because, as neutral molecules, they do not have acidic or basic groups in their structures, which leads to low sensitivity of MS detection 13 . Additionally, the high‐intensity ions from the matrix can interfere with or suppress analyte signals.…”