Department of Chemistry, Washington State University, Pullman, Washington 99163, United States.
GAA Custom Engineering, Kennewick, Washington 99338, United States.
Anal Chem. 2021 Apr 13;93(14):5727-5734. doi: 10.1021/acs.analchem.0c04799. Epub 2021 Apr 2.
The experimental paradigm of one ion packet release per spectrum severely hinders throughput in broadband ion mobility spectrometry (IMS) systems (e.g., drift tube and traveling wave systems). Ion trapping marginally mitigates this problem, but the duty cycle deficit is amplified when moving to high resolution, long pathlength systems. As a consequence, new multiplexing strategies that maximize throughput while preserving peak fidelity are essential for high-resolution IMS separations [e.g., structures for lossless ion manipulations (SLIMs) and multi-pass technologies]. Currently, broadly applicable deconvolution strategies for Hadamard-based ion multiplexing are limited to a narrow range of modulation sequences and do not fully maximize the ion signal generated during separation across an extended path length. Compared to prior Hadamard deconvolution errors that rely upon peak picking or discrete error classification, the masked deconvolution matrix technique exploits the knowledge that Hadamard transform artifacts are reflected about the central, primary signal [i.e., the true arrival time distribution (ATD)]. By randomly inducing mathematical artifacts, it is possible to identify spectral artifacts simply by their high degree of variability relative to the core ATD. It is important to note that the deweighting approach using the masked deconvolution matrix does not make any assumptions about the underlying transform and is applicable to any multiplexing strategy employing binary sequences. In addition to demonstrating a 100-fold increase in the total number of ions detected, the effective deconvolution of data from 5, 6, 7, and 8-bit pseudo-random sequences expands the utility and efficiency of the SLIM platform.
在宽带离子淌度谱（IMS）系统（例如漂移管和行波系统）中，每个光谱释放一个离子包的实验范式严重限制了吞吐量。离子捕集在一定程度上缓解了这个问题，但当迁移到高分辨率、长路径长度系统时，占空比缺陷会被放大。因此，新的复用策略对于高分辨率 IMS 分离至关重要，这些策略可以在保持峰保真度的同时最大化吞吐量[例如，用于无损离子操作的结构（SLIM）和多通技术]。目前，基于 Hadamard 的离子复用的广泛适用的去卷积策略仅限于窄范围的调制序列，并且不能充分最大化在扩展路径长度上分离过程中产生的离子信号。与先前依赖于峰提取或离散误差分类的 Hadamard 去卷积误差相比，掩蔽去卷积矩阵技术利用了 Hadamard 变换伪影反映在中心、主要信号（即真实到达时间分布（ATD））周围的知识。通过随机引入数学伪影，可以通过它们相对于核心 ATD 的高度可变性来简单地识别光谱伪影。需要注意的是，使用掩蔽去卷积矩阵的加权方法不依赖于底层变换，适用于采用二进制序列的任何复用策略。除了证明检测到的离子总数增加了 100 倍之外，来自 5、6、7 和 8 位伪随机序列的数据的有效去卷积扩展了 SLIM 平台的实用性和效率。
