Cluster of Excellence Macromolecular Complexes, Institute of Pharmaceutical Chemistry, Goethe University, Frankfurt, Germany.
Anal Chem. 2010 Feb 1;82(3):922-9. doi: 10.1021/ac902130h.
A simple, sensitive, and fast matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) method was developed for the determination of acetylcholine (ACh) and choline (Ch) in microdialysis samples. An optimized dried droplet preparation with the common matrix alpha-cyano-4-hydroxycinnamic acid (CHCA) was used. Limits of detection [signal-to-noise ratio (S/N) = 3] of 0.3 fmol/microL for ACh and 20 fmol/microL for Ch were found using standards diluted in artificial cerebrospinal fluid (aCSF). The limit of quantification (LOQ) for ACh was 1 fmol/microL, and excellent linearity (R(2) = 0.9996) was maintained over the range of 1-1000 fmol/microL. Choline was quantified over the range of 0.1-50 pmol/microL, also with excellent linearity (R(2) = 0.9995). Good accuracy and precision were obtained for all concentrations within the range of the standard curve. The developed method was successfully used for the determination of ACh and Ch in mouse brain microdialysis samples. The samples were quantified by a calibration curve and also by the method of standard addition. Despite the high salt content of the perfusion fluid (>150 mM), a direct measurement was possible. To the authors' knowledge, this is the first published method to determine acetylcholine and choline in microdialysis samples by MALDI-TOF MS. The method presented significantly reduces the needed analysis time, as only approximately 10 s/sample is required, and it is also possible to improve the temporal resolution, because only approximately 1 microL of sample is needed.
建立了一种简单、灵敏、快速的基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）法，用于测定微透析样品中的乙酰胆碱（ACh）和胆碱（Ch）。采用优化的干液滴制备方法，使用常见基质α-氰基-4-羟基肉桂酸（CHCA）。在人工脑脊液（aCSF）中稀释标准品，检测限（信噪比（S/N）=3）为 ACh 0.3 fmol/μL，Ch 20 fmol/μL。ACh 的定量限（LOQ）为 1 fmol/μL，在 1-1000 fmol/μL 范围内保持良好的线性（R²=0.9996）。Choline 在 0.1-50 pmol/μL 范围内也具有良好的线性（R²=0.9995）。在标准曲线范围内的所有浓度均获得了良好的准确性和精密度。该方法成功用于测定小鼠脑微透析样品中的 ACh 和 Ch。样品通过校准曲线和标准加入法进行定量。尽管灌注液中的盐含量很高（>150 mM），但可以直接进行测量。据作者所知，这是第一个通过 MALDI-TOF MS 测定微透析样品中乙酰胆碱和胆碱的方法。该方法大大减少了所需的分析时间，因为每个样品仅需要约 10 s，并且还可以提高时间分辨率，因为每个样品仅需要约 1 μL。
