演題概要

2P-04

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MALDIにおける正負イオンペアの再結合確率に与えるパラメータの検討

(¹新潟薬大・ ²新潟薬大院・ ³新大病院)
鈴木奏子¹・ 辰口杏奈¹・ 土田彩音¹・ 小林将文^2,3・ 城田起郎¹・ ^o星名賢之助^1,2

In MALDI, the formation of positive and negative ions competes with their recombination, leading to the detection of surviving ions. This study investigates the influence of various parameters on the ion recombination process in MALDI. MALDI spectra of aspartic acid were measured using a Bruker Autoflex III with CHCA and DHB matrices. The effects of extraction delay time (t_ex), extraction electric field (E_ex), and laser intensity on ion signal intensities were examined. The results showed an exponential decrease in ion signals with increasing tex, with a time constant of 3-7 × 10^-3 ns^-1. The signal intensity increased with E_ex, indicating that the electric field suppresses ion recombination. The laser intensity had no significant effect on the ion formation and recombination processes within the studied range. The relationship between the detected ion count, initial ion count, t_ex, and E_ex can be described by a model incorporating a sigmoid-type recombination suppression constant. This study provides insights into the mechanism of the initial MALDI process and can guide instrument design for improved sensitivity. The interpretation of the model parameters based on experimental data and numerical simulations will be presented.