Optimization of ion trajectories in a dynamically harmonized Fourier‐transform ion cyclotron resonance cell using a design of experiments strategy

Abstract

Rationale With the recent introduction of the dynamically harmonized Fourier‐transform ion cyclotron resonance (FT‐ICR) cell, the complexity of tuning has expanded drastically, and fine‐tuning of the direct current voltages is required to optimize the ion cloud movement. As this adjustment must typically be performed manually, more reliable computational methods would be useful. Methods Here we propose a computational method based on a design of experiments (DoE) strategy to overcome the limits of classical manual tuning. This DoE strategy was exemplarily applied on a 12 T FT‐ICR instrument equipped with a dynamically harmonized ICR cell. The chemometric approach, based on a central composite face (CCF) design, was first applied to a reference material (sodium trifluoroacetate) allowing for the evaluation of the primary cell parameters. Eight factors related to shimming and gating were identified. The summed intensity of the signal corresponding to the even harmonics was defined as one quality criterion. Results The DoE response allowed for rapid and complete mapping of cell parameters resulting in an optimized parameter set. The new set of cell parameters was applied to the study of an ultra‐complex sample: Tholins, an ultra‐complex mixture that mimics the haze present on Titan, was chosen. We observed a substantial improvement in mass spectrometric performance. The sum of signals related to harmonics was decreased by a factor of three (from 4% for conventional tuning to 1.3%). Furthermore, the dynamic range was also increased, which in turn led to an increase in attributed peaks by 13%. Conclusions This computational procedure based on an experimental design can be applied to any other mass spectrometric parameter optimization problem. This strategy will lead to a more transparent and data‐driven method development.

Direct Insertion Analysis of Polymer-Modified Bitumen by Atmospheric Pressure Chemical Ionization Ultrahigh-Resolution Mass Spectrometry

“…The dynamically harmonized cell (Paracell) was tuned following a published procedure. 40 For the temperature behavior analyses, source and acquisition parameters were kept the same, but instead of a fixed nebulizer gas temperature of 400 °C, the temperature was ramped between 250 and 450 °C. For these experiments, the temperature was incremented by 2 °C per scan.…”

“…These settings result in a mass spectrometric resolving power of 650 000 at m / z 400. The dynamically harmonized cell (Paracell) was tuned following a published procedure …”

Metabolome Exploration by High-Resolution Mass Spectrometry Methodologies of Two New Yeast Species: Starmerella reginensis and Starmerella kourouensis

“…1/10,000 diluted samples were directly injected and ionized with an electrospray ionization source operated in positive and in negative ionization modes. Previous studies inspired the source and analyzer parameters that guarantee sensitive and robust analyses , (Table S1). A resolution of 600,000 at m / z 200 was reached.…”

Comparison of Silica and Cellulose Stationary Phases to Analyze Bitumen by High-Performance Thin-Layer Chromatography Coupled to Laser Desorption Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

“…The analog signal was amplified and digitalized with 8 million points, which resulted in the recording of transient of about 3.35 s that was transformed into the corresponding frequency domain by Fourier transform (one zero-fill and half-sine apodization). The dynamically harmonized cell (Paracell) was tuned following a published procedure . Under these conditions, a mass resolution of 900 000 at m / z 400 was obtained.…”