In ultraviolet matrix-assisted laser desorption/ionization mass spectrometry (UV-MALDI MS) matrix compound optical absorption governs the uptake of laser energy, which in turn has a strong influence on experimental results. Despite this, quantitative absorption measurements are lacking for most matrix compounds. Furthermore, despite the use of UV-MALDI MS to detect a vast range of compounds, investigations into the effects of laser energy have been primarily restricted to single classes of analytes. We report the absolute solid state absorption spectra of the matrix compounds α-cyano-4-hydroxycinnamic acid (CHCA), para-nitroaniline (PNA), 2-mercaptobenzothiazole (MBT), 2,5-dihydroxybenzoic acid (2,5-DHB), and 2,4,6-trihydroxyacetophenone (THAP). The desorption/ionization characteristics of these matrix compounds with respect to laser fluence was investigated using mixed systems of matrix with either angiotensin II, PC(34:1) lipid standard, or haloperidol, acting as representatives for typical classes of analyte encountered in UV-MALDI MS. The first absolute solid phase spectra for PNA, MBT, and THAP are reported; additionally, inconsistencies between previously published spectra for CHCA are resolved. In light of these findings, suggestions are made for experimental optimization with regards to matrix and laser wavelength selection. The relationship between matrix optical cross-section and wavelength-dependant threshold fluence, fluence of maximum ion yield, and R, a new descriptor for the change in ion intensity with fluence, are described. A matrix cross-section of 1.3 × 10^–17 cm^–2 was identified as a potential minimum for desorption/ionization of analytes.

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在紫外基质辅助激光解吸/电离质谱（UV-MALDI MS）中，基质化合物的光吸收控制着激光能量的吸收，这反过来对实验结果有很大的影响。尽管如此，大多数基质化合物仍缺乏定量吸收测量。此外，尽管使用UV-MALDI MS检测大量化合物，但对激光能量影响的研究主要限于单类分析物。我们报告了基质化合物α-氰基-4-羟基肉桂酸（CHCA）的绝对固态吸收光谱，对位-硝基苯胺（PNA），2-巯基苯并噻唑（MBT），2,5-二羟基苯甲酸（2,5-DHB）和2,4,6-三羟基苯乙酮（THAP）。使用基质与血管紧张素II，PC（34：1）脂质标准品或氟哌啶醇的混合系统研究了这些基质化合物相对于激光通量的解吸/电离特性，这些代表了UV-中遇到的典型分析物类别MALDI MS。报道了PNA，MBT和THAP的第一个绝对固相谱；此外，可以解决以前发布的CHCA光谱之间的不一致问题。根据这些发现，就矩阵和激光波长选择方面的实验优化提出了建议。矩阵光学截面与波长相关阈值注量，最大离子产量的注量之间的关系，描述了R，它是离子强度随注量变化的新描述符。1.3×10 ^–17 cm ^–2的基质横截面被确定为分析物解吸/电离的潜在最小值。

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