Petroleomics by design of experiments in ESI(±)FT-ICR MS analysis

\The Fourier Transform Ion Cyclotron Resonance mass spectrometer (FT-ICR MS) is an efficient and widely used analytical instrument for characterizing complex organic mixtures at the molecular level. The Electrospray ionization (ESI) source is commonly used for identifying heteroatomic compounds (N, O, S) in crude oil. The high complexity of the sample provides a wealth of information, and therefore, processing and visualization programs are used to facilitate data interpretation. Several experimental configurations of parameters exist for the acquisition of ESI(+)FT-ICR MS and ESI(-)FT-ICR MS of crude oils. In this context, the design of experiments can help obtain optimal test conditions. The objective of this work was to identify the most significant experimental parameters among the 11 available (concentration, skimmer, time of flight (TOF), flow rate, ion accumulation time (IAT), accumulated scans (scans), dry temperature, capillary, dry gas, nebulizer, and collision voltage (CV)) for the acquisition of ESI(+/-)FT-ICR MS in Petroleomics using design of experiments by Plackett Burman and full design. Global desirability was used as a response parameter obtained from MS data (resolution, signal-to-noise ratio, signal-to-charge ratio signal with highest absolute intensity, total signals, low mass error, and high mass error). Additionally, responses from the mass spectra processing program were also used (the number of molecular formulas, molecular formulas of the majority class, average error, assignment percentage, amount of DBE in the plot of DBE versus carbon number (CN), and the relationship between the number of zero intensities and the number of DBE values in the plot of DBE versus CN). The study found that concentration and flow rate were the most significant experimental parameters for ESI(+), while for ESI(-), TOF and CV were the most significant experimental parameters. Lower concentration (0.1-0.5 mg/mL) and higher flowrate (5-6 mu L/min) improved the desirability by ESI(+), higher values of CV (50 V) improved the desirability by ESI(-) for crude oil analysis.